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1

Al 2O 3\\/Ti interlayer\\/AISI 304 diffusion bonded joint  

Microsoft Academic Search

Sintered alumina and AISI 304 stainless-steel discs were joined at 900°C by solid state diffusion bonding, making use of a Ti foil acting as thermal stress relief interlayer. The microstructure of the two interfaces thus formed, that is, Al2O3\\/Ti and Ti\\/AISI 304 was investigated by a variety of characterization techniques such as scanning and transmission electron microscopy (TEM), energy-dispersive X-ray

A. M Kliauga; D Travessa; M Ferrante

2001-01-01

2

Comparative evaluation of laser-assisted micro-milling for AISI 316, AISI 422, TI-6AL-4V and Inconel 718 in a side-cutting configuration  

NASA Astrophysics Data System (ADS)

This paper is focused on numerical modeling and experimental evaluation of laser-assisted micro-milling (LAMM). An experimental setup consisting of a 25 W CO2 laser, three-axis CNC linear stages and a high-speed spindle was used to implement the LAMM process. Micro-endmills between 100 and 300 µm in diameter were used to perform side-cutting operations with and without laser preheat on four materials: AISI 316, AISI 422, Ti-6Al-4V and Inconel 718. A three-dimensional transient finite-volume-based thermal model was used to analytically predict appropriate process parameters on the basis of material-removal temperatures. The effects of LAMM on the machined surface finish, edge burrs, tool wear and workpiece microstructure were evaluated experimentally.

Shelton, Jonathan A.; Shin, Yung C.

2010-07-01

3

Joining of Al 6061 alloy to AISI 1018 steel by combined effects of fusion and solid state welding  

Microsoft Academic Search

The joining of a 6-mm thickness Al 6061 to AISI 1018 steel has been performed by the combined effects of fusion and solid state welding. The process is derived from friction stir welding (FSW) but with an adjustable offset of the probe location with respect to the butt line. Metallographic studies by optical microscopy, electron probe microscopy, and the utilization

C. M Chen; R Kovacevic

2004-01-01

4

Transient liquid-phase insert metal bonding of Al2O3 and AISI 304 stainless steel  

Microsoft Academic Search

Transition liquid-phase insert metal bonding of Al2O3 and AISI 304 stainless steel based materials is investigated. This joining\\u000a technique allows the continuous replenishment of the active solute which is consumed by the chemical reaction that occurs\\u000a at the ceramic\\/filler metal interface. Replenishment is facilitated by employing a sandwich of filler materials comprising\\u000a tin-based filler metal and amorphous Cu50Ti50 or NiCrB

Y. ZHAI; T. H. NORTH; J REN

1997-01-01

5

High temperature wear resistance of (TiAl)N PVD coating on untreated and gas nitrided AISI H13 steel with different heat treatments  

Microsoft Academic Search

The wear resistance of a PVD (Ti0.7Al0.3)N coating deposited on an as-received and gas nitrided AISI H13 has been examined by using ball-on-disc tests at room temperature and at 600°C. In order to determine the influence of a previous heat treatment on this type of steel on the wear resistance of the (Ti0.7Al0.3)N coating, two commercial heat treatments were employed

R. Rodríguez-Baracaldo; J. A. Benito; E. S. Puchi-Cabrera; M. H. Staia

2007-01-01

6

The effect of bond coat on mechanical properties of plasma-sprayed Al 2O 3 and Al 2O 3–13 wt% TiO 2 coatings on AISI 316L stainless steel  

Microsoft Academic Search

In this study, Al2O3 and Al2O3–13wt% TiO2 were plasma sprayed onto AISI 316L stainless-steel substrate with and without Ni–5wt% Al as bond coat layer. The coated specimens were characterized by optical microscopy, metallography and X-ray diffraction (XRD). Bonding strength of coatings were evaluated in accordance with the ASTM C-633 method. It was observed that the dominant phase was Al2O3 for

?enol Y?lmaz; Mediha Ipek; Gözde F. Celebi; Cuma Bindal

2005-01-01

7

Microstructure and mechanical properties of CrAlN coatings deposited by modified ion beam enhanced magnetron sputtering on AISI H13 steel  

Microsoft Academic Search

CrAlN coatings were deposited on silicon and AISI H13 steel substrates using a modified ion beam enhanced magnetron sputtering\\u000a system. At the modified ion beam bombardment, the effects of bias voltage and Al\\/(Cr + Al) ratio on microstructure and mechanical\\u000a properties of the coatings were studied. The X-ray diffraction data showed that all CrAlN coatings were crystallized in the\\u000a cubic NaCl B1

Chunyan Yu; Shebin Wang; Linhai Tian; Tianbao Li; Bingshe Xu

2009-01-01

8

Wear on tool steel AISI M2, D6 and 52100 coated with Al 2O 3 by the MOCVD process  

Microsoft Academic Search

Present work investigates the wear resistance of tool steels and 52100 steel coated with Al2O3 by MOCVD process. The wear tests by sliding and abrasion were performed in a pin-on-disk and ball-on-disk apparatus whose pin and ball substrates were steels fabricated from AISI M2, D6 and 52100. The MOCVD coating processes were carried out in a research laboratory apparatus at

José Divo Bressan; Giovanni A. Battiston; Rosalba Gerbasi; Deivid Paganini Daros; Leonidas Mamani Gilapa

2006-01-01

9

Mechanical and tribological properties enhancement of heat treated AISI 4340 steel by using a TiN\\/TiAlN multilayer coating system Mejoramiento de las propiedades mecánicas y tribológicas del acero AISI 4340 tratado térmicamente, utilizando un recubrimiento de multicapas de TiN\\/TiAlN  

Microsoft Academic Search

TiN\\/TiAlN (titanium nitride\\/titanium aluminum nitride) multilayer were deposited by d.c. reactive magnetron sputtering using titanium and aluminum targets with 10 cm in diameter and 99.9% purity in an argon\\/nitrogen (Ar\\/ N) atmosphere, applying a substrate temperature of 300°C and a pressure of 7x10-3 mbar. Silicon (100) and heat treated AISI 4340 steel samples with a hardness of 54 Rockwell C

Gilberto Bejarano; Julio Caicedo; Juan Muñoz Saldaña

10

Long-term corrosion investigation of AISI 316L, Co-28Cr-6Mo, and Ti-6Al-4V alloys in simulated body solutions  

NASA Astrophysics Data System (ADS)

The long-term weight loss, ion release and surface composition of AISI 316L, the Co-28Cr-6Mo and Ti-6Al-4V alloys were investigated in phosphate buffered solutions (PBS) with various bovine serum albumin (BSA) concentrations. All the samples lost weight up to 14 weeks and then started to gain weight. This can be explained by precipitation of dissolved ions on the surface after 14 weeks of immersion. The quantities of the dissolved ions were measured in immersed solution for 8, 14 and 22 weeks by induced coupled plasma-optical emission spectrometer (ICP-OES). The amounts of Fe released from 316L, and Co and Mo released from the Co-28Cr-6Mo alloy decreased after 14 weeks of immersion in PBS and BSA solutions. This observation coincides with the weight change of the samples. The oxide layer composition and concentration of the specimens exposed to solutions for 22 weeks were identified by X-ray photoelectron spectroscopy (XPS) analysis. The XPS results revealed that chromium is the main component of the 316L and Co-28Cr-6Mo alloy. The high Cr concentration of the 316L and Co-Cr-Mo oxide layer corresponds with the slow dissolution rate of Cr compared to other alloying elements of the 316L and Co-28Cr-6Mo alloy.

Karimi, Shima; Nickchi, Tirdad; Alfantazi, Akram M.

2012-06-01

11

Wear mechanisms and tool performance of TiAlN PVD coated inserts during machining of AISI 4140 steel  

Microsoft Academic Search

The tribological influences of PVD-applied TiAlN coatings on the wear of cemented carbide inserts and the microstructure wear behaviors of the coated tools under dry and wet machining are investigated. The turning test was conducted with variable high cutting speeds ranging from 210 to 410m\\/min. The analyses based on the experimental results lead to strong evidences that conventional coolant has

Samir K. Khrais; Y. J. Lin

2007-01-01

12

Chemical, morphological and nano-mechanical characterizations of Al 2O 3 thin films deposited by metal organic chemical vapour deposition on AISI 304 stainless steel  

Microsoft Academic Search

Amorphous alumina coatings of different thickness have been deposited on AISI 304 stainless steel substrates by MOCVD in a hot wall reactor at 380°C under O2\\/H2O atmosphere. The used aluminium precursor was the high volatile and easy to prepare dimethyl-aluminum-isopropoxide. Selected films were annealed in N2 and O2 atmosphere at 500 and 700°C to evaluate the effects of the thermal

M. Natali; G. Carta; V. Rigato; G. Rossetto; G. Salmaso; P. Zanella

2005-01-01

13

Microstructure, Mechanical, and Scratch Resistance Properties of TiAlCrNbN-Graded Composite Coating Deposited on AISI H13 Steel Substrate with Pulsed DC Closed Field Unbalanced Magnetron Sputtering Method  

NASA Astrophysics Data System (ADS)

Structure and adhesion properties of TiAlCrNbN coatings were investigated. These coatings were deposited onto AISI H13 steel substrate using pulsed dc closed field unbalanced magnetron sputtering at different deposition parameters including duty cycle, bias voltage, and working pressure. The coatings have been characterized by X-ray diffraction, scanning electron microscopy and energy dispersive spectroscopy. The TiAlCrNbN-graded composite coatings have a dense and columnar structure. The X-ray diffraction patterns of coatings exhibited predominantly c-TiAlCrN, h-NbN, and h-TiAlN reflections. Scratch resistance test showed that the highest adhesion strength was attained as 68 N at 2.5 ?s duty time, 100 V bias voltages, and 3 × 10-3 Torr deposition parameters. The lowest adhesion strength was obtained as 55 N at 0.5 ?s duty time, 50V bias voltage, and 2 × 10-3 Torr deposition parameters.

Kara, Levent; Küçükömero?lu, Tevfik; Baran, Özlem; Efeo?lu, ?hsan; Yamamoto, Kenji

2014-04-01

14

AISI direct steelmaking program  

SciTech Connect

AISI with co-funding from DOE has initiated a research and development program aimed at the development of a new process for direct steelmaking, and the program is discussed in this document. The project is expected to cost about $30 million over a three-year period, with the government providing approximately 77 percent of the funds and AISI the balance. In contrast to current steelmaking processes which are largely open and batch, the direct steelmaking process would be closed and continuous. Further, it would use coal directly, thereby avoiding the need for coke ovens. The second year of the Direct Steelmaking Program (November 29, 1989, through November 28, 1990) was a year of significant accomplishment. The various research programs proceeded essentially on schedule and the pilot plant, the centerpiece of the program, was completed about three months behind schedule but began operation in almost a picture-perfect manner. This report presents the last years accomplishments.

Aukrust, E.

1991-01-09

15

Effect of cooling rate on hardness and microstructure of AISI 1020, AISI 1040 and AISI 1060 Steels  

Microsoft Academic Search

The object of the present work is to investigate the effect of cooling rate on microstructure and mechanical properties of AISI 1020, AISI 1040 and AISI 1060 steels. The samples were heated and treated at 1250°K for 4 h and subsequently were cooled by three different methods. For this purpose, the microhardness and microstructure of these steels after heat treatment

Adnan Çalik

16

Ion release and surface oxide composition of AISI 316L, Co-28Cr-6Mo, and Ti-6Al-4V alloys immersed in human serum albumin solutions.  

PubMed

The long-term weight loss, ion release, and surface composition of 316L, Co-28Cr-6Mo and Ti-6Al-4V alloys were investigated in a simulated body environment. The samples were immersed in phosphate-buffered saline (PBS) solutions with various human serum albumin (HSA) concentrations for 8, 14, and 22weeks. The specimens initially lost weight up to 14weeks and then slightly gained weight. The analysis of the released ions was performed by induced coupled plasma-optical emission spectrometer (ICP-OES). The results revealed that the precipitation of the dissolved Fe and Co could cause the weight gain of the 316L and Co-28Cr-6Mo alloys. The surface chemistry of the specimens was determined by X-ray photoelectron spectroscopy (XPS). The XPS analysis of Co-28Cr-6Mo alloy showed that the interaction of Mo with HSA is different from Mo with bovine serum albumin (BSA). This was also observed for Na adsorption into the oxide layer of Ti-6Al-4V alloy in the presence of HSA and BSA. PMID:24857512

Karimi, Shima; Alfantazi, Akram M

2014-07-01

17

Oxidation protection of AISI H13 steel by high current pulsed electron beam treatment  

Microsoft Academic Search

A duplex surface treatment scheme, combining arc deposition with high-current pulsed electron beam (HCPEB) post treatment, has been applied to rapid surface alloying of AISI H13 steel in order to improve high-temperature oxidation resistance. An Al coating as thick as 10 ?m was deposited on AISI H13 by arc deposition. The coating was then post-treated with HCPEB. Due to rapid

Jianxin Zou; Aimin Wu; Chuang Dong; Shenzhi Hao; Zhenmin Liu; Haitao Ma

2004-01-01

18

Surface fatigue and failure characteristics of hot-forged powder metal AISI 4620, AISI 4640, and machined AISI 4340 steel spur gears  

NASA Technical Reports Server (NTRS)

Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel gear materials. The as-forged and unground AISI 4620 gear exhibited a 10 percent fatigue life that was approximately one-fourth of that for AISI 9310 and less than one-half that for the AISI 4340 gears. The forged and finish ground AISI 4620 gears exhibited a 10 percent life, approximately 70 percent that of AISI 9310 and slightly better than that of AISI 4340. The AISI 4640 hot forged gears had less fracture toughness and slightly less fatigue life than the AISI 4620 test gears.

Townsend, Dennis P.

1987-01-01

19

Mechanical properties of martensitic alloy AISI 422  

SciTech Connect

HT9 is a martensitic stainless steel that has been considered for structural applications in liquid metal reactors (LMRs) as well as in fusion reactors. AISI 422 is a commercially available martensitic stainless steel that closely resembles HT9, and was studied briefly under the auspices of the US LMR program. Previously unpublished tensile, fracture toughness and charpy impact data on AISI 422 were re-examined for potential insights into the consequences of the compositional differences between the two alloys, particularly with respect to current questions concerning the origin of the radiation-induced embrittlement observed in HT9.

Hamilton, M.L. [Pacific Northwest Lab., Richland, WA (United States); Huang, F.H.; Hu, Wan-Liang [Westinghouse Hanford Co., Richland, WA (United States)

1992-06-01

20

Mechanical properties of martensitic alloy AISI 422  

SciTech Connect

HT9 is a martensitic stainless steel that has been considered for structural applications in liquid metal reactors (LMRs) as well as in fusion reactors. AISI 422 is a commercially available martensitic stainless steel that closely resembles HT9, and was studied briefly under the auspices of the US LMR program. Previously unpublished tensile, fracture toughness and charpy impact data on AISI 422 were reexamined for potential insights into the consequences of the compositional differences between the two alloys, particularly with respect to current questions concerning the origin of the radiation-induced embrittlement observed in HT9. 8 refs, 8 figs.

Huang, F.H.; Hu, W.L. (Westinghouse Hanford Co., Richland, WA (United States)); Hamilton, M.L. (Pacific Northwest Lab., Richland, WA (United States))

1992-09-01

21

Fatigue behaviour of AISI 304 steel to AISI 4340 steel welded by friction welding  

Microsoft Academic Search

In the presented study, The weldability of AISI 304 austenitic stainless steel to AISI 4340 steel joined by friction welding\\u000a in different rotational speeds and fatigue behaviour of friction-welded samples were investigated. Tension tests were applied\\u000a to welded parts to obtain the strength of the joints. The welding zones were examined by scanning electron microscopy (SEM)\\u000a and analyzed by energy

A. Hasçalik; E. Ünal; N. Özdemir

2006-01-01

22

The kinetics and mechanism of multi-component diffusion on AISI 1045 steel  

Microsoft Academic Search

A multi-component diffusion study of boron, chromium, aluminum and silicon on an AISI 1045 steel substrate has been carried out by pack cementation. A commercial boriding powder (Ekabor-3) and an Fe–Cr alloy powder plus NH4Cl activator make up 30wt% of the pack, and 70wt% of Al2O3 serves as an inert diluent and supply source of aluminum atoms. The structure and

Fan-Shiong Chen; Kuo-Liang Wang

1999-01-01

23

Surface Fatigue and Failure Characteristics of Hot Forged Powder Metal AISI 4620, AISI 4640, and Machined AISI 4340 Steel Spur Gears.  

National Technical Information Service (NTIS)

Spur gear surface fatigue endurance tests were conducted to investigate hot forged powder metal AISI 4620 and 4640 steel for use as a gear material, to determine endurance characteristics and to compare the results with machined AISI 4340 and 9310 steel g...

D. P. Townsend

1986-01-01

24

Pack Cementation Coatings for High-Temperature Oxidation Resistance of AISI 304 Stainless Steel  

NASA Astrophysics Data System (ADS)

Aluminum and titanium are deposited on the surface of steel by the pack cementation method to improve its hot-corrosion and high-temperature oxidation resistance. In this research, coatings of aluminum and titanium and a two-step coating of aluminum and titanium were applied on an AISI 304 stainless steel substrate. The coating layers were examined by carrying out scanning electron microscopy (SEM) and x-ray diffraction (XRD). The SEM results showed that the aluminized coating consisted of two layers with a thickness of 450 ?m each, the titanized coating consisted of two layers with a thickness of 100 ?m each, and the two-step coatings of Al and Ti consisted of three layers with a thickness of 200 ?m each. The XRD investigation of the coatings showed that the aluminized coating consisted of Al2O3, AlCr2, FeAl, and Fe3Al phases; the titanized layers contained TiO2, Ni3Ti, FeNi, and Fe2TiO5 phases; and the two-step coating contained AlNi, Ti3Al, and FeAl phases. The uncoated and coated specimens were subjected to isothermal oxidation at 1050 °C for 100 h. The oxidation results revealed that the application of a coating layer increased the oxidation resistance of the coated AISI 304 samples as opposed to the uncoated ones.

Zandrahimi, Morteza; Vatandoost, Javad; Ebrahimifar, Hadi

2012-10-01

25

Characterization of borided AISI 316L stainless steel implant  

Microsoft Academic Search

The present study reports on characterization of borided AISI 316L stainless steel implant. Boronizing heat treatment was performed on a cylindrical bar of AISI 316L austenitic surgical stainless steel with a diameter of 2mm and a length of 10mm using slurry salt bath consisting of borax, boric acid and ferro-silicon. The susbstrate AISI 316L was essentially containing 0.022wt% C, 0.79wt%

I. Özbek; B. A. Konduk; C. Bindal; A. H. Ucisik

2002-01-01

26

The effects of casting and forging processes on joint properties in friction-welded AISI 1050 and AISI 304 steels  

Microsoft Academic Search

The aim of the present study was to investigate the effects of investment casting and forging process on the microstructure\\u000a and mechanical properties of friction weldments, AISI 1050–AISI 304. A continuous-drive friction welding device with the automatic\\u000a control ability of friction time and forging pressure was designed and constructed. Factorial design of experiments was performed\\u000a to join investment cast AISI

Tolga Y. Sunay; Mumin Sahin; Sabri Altintas

2009-01-01

27

Characterization of AISI 4140 borided steels  

NASA Astrophysics Data System (ADS)

The present study characterizes the surface of AISI 4140 steels exposed to the paste-boriding process. The formation of Fe 2B hard coatings was obtained in the temperature range 1123-1273 K with different exposure times, using a 4 mm thick layer of boron carbide paste over the material surface. First, the growth kinetics of boride layers at the surface of AISI 4140 steels was evaluated. Second, the presence and distribution of alloying elements on the Fe 2B phase was measured using the Glow Discharge Optical Emission Spectrometry (GDOES) technique. Further, thermal residual stresses produced on the borided phase were evaluated by X-ray diffraction (XRD) analysis. The fracture toughness of the iron boride layer of the AISI 4140 borided steels was estimated using a Vickers microindentation induced-fracture testing at a constant distance of 25 ?m from the surface. The force criterion of fracture toughness was determined from the extent of brittle cracks, both parallel and perpendicular to the surface, originating at the tips of an indenter impression. The fracture toughness values obtained by the Palmqvist crack model are expressed in the form KC( ?/2) > KC > KC(0) for the different applied loads and experimental parameters of the boriding process.

Campos-Silva, I.; Ortiz-Domínguez, M.; López-Perrusquia, N.; Meneses-Amador, A.; Escobar-Galindo, R.; Martínez-Trinidad, J.

2010-02-01

28

Development and characterization of sol–gel silica–alumina composite coatings on AISI 316L for implant applications  

Microsoft Academic Search

Sol–gel alumina coatings were deposited on medical grade stainless steel (AISI 316L) with an intermediate layer of silica by dip-coating method. The coatings obtained were homogeneous, crack-free and consisted of low crystalline ?-Al2O3 along with some boehmite phase. EDAX revealed the presence of only Al in the film. The corrosion performance of alumina-coated stainless steel was evaluated by electrochemical polarization,

S. K. Tiwari; T. Mishra; M. K. Gunjan; A. S. Bhattacharyya; T. B. Singh; R. Singh

2007-01-01

29

Optimization and control of drilling burr formation of AISI 304L and AISI 4118 based on drilling burr control charts  

Microsoft Academic Search

Control charts for drilling burr formation for stainless, AISI 304L, and low alloy steel, AISI 4118, were developed. Split point twist drills are used for the experiments of this work. A Drilling Burr Control Chart, based on experimental data, is a tool for prediction and control of drilling burrs. Burr classification was carried out based on the geometric characteristics, burr

Jinsoo Kim; Sangkee Min; David A. Dornfeld

2001-01-01

30

Hot hardness characteristics of ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C, and Super Nitralloy  

NASA Technical Reports Server (NTRS)

Short-term hot hardness studies were performed with ausformed AISI M-50, Matrix 2, WD-65, modified AISI 440-C (14-4-1) and case hardened Super Nitralloy. Hardness levels of each material were measured at elevated temperatures in an electric furnace with a low oxygen environment. Test temperatures ranged from 294 to 877 K. The hot hardness characteristics of the ausformed AISI-M-50, Matrix 2 WD-65, and modified AISI 440-C were the same as those determined for high-speed tool steels. Hot hardness for these steels can be predicted within one point Rockwell C. The hot hardness characteristics of both the case and core of Super Nitralloy were superior to AISI 52100 but inferior to the high-speed tool steels. The short-term Rockwell C hardness at temperature for the Super Nitralloy material between 294 and 769 K can be predicted within one point Rockwell C hardness.

Chevalier, J. L.; Dietrich, M. W.; Zaretsky, E. V.

1973-01-01

31

An investigation on borided AISI 1020 steel  

NASA Astrophysics Data System (ADS)

In this study, we investigated some properties of borided AISI 1020 steel. Boronizing heat treatment was carried out at 800°C, 875°C and 950°C for 2, 4, 6 and 8 h using Ekabor 1 powders. The hardness of borides formed on the steel substrate measured via Vickers indenter was about 1500 HVN. The thickness of boride layers depending on the process temperature and time was ranged from 20.5 to 216 ?m. The presence of FeB boride was determined by XRD analysis. SEM microscope studies showed that the borides formed on the AISI 1020 steel have columnar nature. Kinetics studies reveal a parabolic relationship between layer depth and process time, and the activation energy is calculated as 164,356 kJ/mol. Moreover, an attempt was made to investigate the possibility of predicting the iso-thickness of boride layer and to establish an empirical relationship between process parameters of boriding and boride layer for industrial applications.

Altinsoy, I.; Efe, F. G. Celebi; Ipek, M.; Ozbek, I.; Zeytin, S.; Bindal, C.

2013-12-01

32

Study of face milling of hardened AISI D3 steel with a special design of carbide tools  

Microsoft Academic Search

This paper studies the impact of a special carbide tool design on the process viability of the face milling of hardened AISI\\u000a D3 steel (with a hardness of 60 HRC), in terms of surface quality and tool life. Due to the advances in the manufacturing\\u000a of PVD AlCrN tungsten carbide coated tools, it is possible to use them in the manufacturing

H. R. Siller; C. Vila; C. A. Rodríguez; J. V. Abellán

2009-01-01

33

Fracture toughness of AISI M2 and AISI M7 high-speed steels  

Microsoft Academic Search

A study has been made of the fracture toughness of AISI M2 and M7 high-speed steels. Fracture toughness of these steels was\\u000a found to depend principally on austenitizing temperature and hardness level. The results are highly reproducible. At usual\\u000a working hardness levels the fracture toughness of M7 and M2 were approximately equal. Instrumented unnotched Charpy tests\\u000a showed M2 to have

A. R. Johnson

1977-01-01

34

Fracture toughness of AISI M2 and AISI M7 high-speed steels  

Microsoft Academic Search

A study has been made of the fracture toughness of AISI M2 and M7 high-speed steels. Fracture toughness of these steels was found to depend principally on austenitizing temperature and hardness level. The results are highly reproducible. At usual working hardness levels the fracture toughness of M7 and M2 were approximately equal. Instrumented unnotched Charpy tests showed M2 to have

A. R. Johnson

1977-01-01

35

Metallographic Studies of Hydrogen-Embrittled AISI Type 1018 Steel.  

National Technical Information Service (NTIS)

Metallographic and fractographic studies of AISI Type 1018 steel disks, pressurized to rupture in either hydrogen or oxygen gas showed that the adverse effects of hydrogen were influenced by the inclusion content of the steel. The hydrogen embrittlement p...

J. A. Wagner M. R. Louthan M. R. Louthan

1982-01-01

36

Thermal Linear Expansion of Nine Selected AISI Stainless Steels.  

National Technical Information Service (NTIS)

This technical report reviews the available experimental data and information on the thermal linear expansion of nine AISI stainless steels and presents the recommended values from 10 K to near the melting point of the stainless steels. The nine selected ...

P. D. Desai C. Y. Ho

1978-01-01

37

Corrosion of AISI 304 Stainless Steel in Polluted Seawater.  

National Technical Information Service (NTIS)

The sequence of microbiofouling settlement on AISI 304 stain steel samples exposed to polluted harbor sea water of a power cooling water intake is studied. The first sites of bacterial colonization are followed by means of scanning electron microscopy dur...

G. Brankevich P. Guiamet H. A. Videla

1987-01-01

38

Effect of particle velocity and impact angle on the corrosion–erosion of AISI 304 and AISI 420 stainless steels  

Microsoft Academic Search

The effect of particle velocity and mean impact angle on the corrosion–erosion of solubilized AISI 304 and quenched and tempered AISI 420 stainless steels was studied. The tests were performed using slurry composed of 0.5M H2SO4+3.5% NaCl and 30wt% quartz particles with 0.21–0.30mm mean diameter. Potentiodynamic curves, AFM and SEM analyses allowed identification of the wear mechanisms and assessment of

D. López; J. P. Congote; J. R. Cano; A. P. Tschiptschin

2005-01-01

39

Effect of aging at 700 °C on precipitation and toughness of AISI 321 and AISI 347 austenitic stainless steel welds  

Microsoft Academic Search

A detailed knowledge of changes in microstructures and mechanical behaviour that occur in austenitic stainless steels with or without Nb\\/Ti-stabilized weld during heat treatment is of great interest, since the ductility and toughness of the material may change drastically after long aging times. Two kinds of materials, i.e. AISI 321 base and without Ti-stabilized weld steel and AISI 347 base

Kaishu Guan; Xiaodong Xu; Hong Xu; Zhiwen Wang

2005-01-01

40

Effects of low-temperature aging on AISI 444 steel  

NASA Astrophysics Data System (ADS)

The consequences of aging at 400 and 475 °C on the mechanical properties, corrosion resistance, and magnetic properties of the ferritic stainless steel (SS) AISI 444 were investigated. Age hardening was measured as a function of aging time at both temperatures and was found to be more intense at 475 °C. The localized corrosion susceptibility increased, while the impact toughness decreased with aging time. These two effects were also more important at 475 °C. Unlike duplex SSs, AISI 444 did not present any variation in coercive force or Curie temperature with aging time. The effects on the Mössbauer spectra were also determined and analyzed.

Souza, José A.; Abreu, Hamilton F. G.; Nascimento, Alex M.; de Paiva, José A. C.; de Lima-Neto, Pedro; Tavares, Sérgio S. M.

2005-06-01

41

Aluminum-silicon co-deposition by FB-CVD on austenitic stainless steel AISI 316  

NASA Astrophysics Data System (ADS)

Aluminum-silicon coatings were deposited on stainless steel AISI 316 in the temperature range of 540 to 560°C by CVD-FBR. It was used a fluidized bed with 2.5% silicon and 7.5% aluminum powder and 90% inert (alumina). This bed was fluidized with Ar and as an activator a mixture of HCl/H2 in ratios of 1/10 to 1/16. Furthermore, the deposition time of the coatings was varied between 45 minutes to 1.5 hours, with a 50% active gas, neutral gases 50%. Thermodynamic simulation was conducted with the Thermocalc software to get the possible compositions and amount of material deposited for the chosen conditions. The coatings presented the follow compounds FeAl2Si, FeAl2 and Fe2Al5. Aluminum-silicon coatings were heat treated to improve its mechanical properties and its behavior against oxidation for the inter diffusion of the alloying elements. The heat treatment causes the aluminum diffuse into the substrate and the iron diffuse into coating surface. This leads to the transformation of the above compounds in FeAl, Al2FeSi, Cr3Si, AlFeNi and AlCrFe.

Marulanda, J. L.; Perez, F. J.; Remolina-Millán, A.

2013-11-01

42

Metallographic studies of hydrogen-embrittled AISI Type 1018 steel  

Microsoft Academic Search

Metallographic and fractographic studies of AISI Type 1018 steel disks, pressurized to rupture in either hydrogen or oxygen gas showed that the adverse effects of hydrogen were influenced by the inclusion content of the steel. The hydrogen embrittlement processes initiate at surface defects and inclusion stringers. The embrittlement sequence then involves a complicated interaction between these failure initiation sites, the

J. A. Wagner; M. R. Louthan

1982-01-01

43

Evaluation of borides formed on AISI P20 steel  

Microsoft Academic Search

This study reports on an evaluation of borides formed on AISI P20 steel substrate. Boronizing was performed at 800, 875 and 950°C for 2, 4, 6 and 8h by using Ekabor 2 powders. The hardness of borides measured by means of Vickers indenter was about 1500 HVN. The depth of boride layers depending on temperature and process time was ranged

I. Uslu; H. Comert; M. Ipek; O. Ozdemir; C. Bindal

2007-01-01

44

Investment cast AISI H13 tooling for automotive applications.  

National Technical Information Service (NTIS)

While many techniques exist for production of soft tooling, for die casting there is limited recent experience with cast tooling. The most common US alloy used for manufacture of die casting tooling is wrought AISI H13. If the performance of the cast mate...

M. C. Maguire M. D. Baldwin P. W. Hochanadel G. R. Edwards

1995-01-01

45

Laser surface hardening of AISI H13 tool steel  

Microsoft Academic Search

An attempt was made to improve the surface hardness and wear properties of AISI H13 tool steel through solid solution hardening and refinement of microstructures using a 200 W fiber laser as a heat generating source. The hardness of laser melted zone was investigated. In order to identify the effect of heat input on the laser melting zone, scanning conditions

Jae-Ho LEE; Jeong-Hwan JANG; Byeong-Don JOO; Young-Myung SON; Young-Hoon MOON

2009-01-01

46

AISI and DOE collaborate on Advanced Process Control Program  

Microsoft Academic Search

In today's steel marketplace with its excess capacity and low prices, a high-quality product is no assurance of success. Competition and survival depend on a high-quality product produced at the lowest possible cost. All steel producers are faced with this challenge. To meet that challenge, the American Iron and Steel Institute (AISI) the Dept. of Energy (DOE) are undertaking a

Kavanagh

1993-01-01

47

PRECIPITACIÓN MARTENSÍTICA EN ACEROS INOXIDABLES AISI 304 - CORROSIÓN BAJO TENSIÓN  

Microsoft Academic Search

Present contribution constitues the research of the specimen stainless steels AISI 304, testing at different load compression. The material testing presented magnetic properties when de load compression was 99 KNI. The micrograph shows the transformation the phase austenitic to martensitic. The stress corrosion cracking susceptibility of the steel in 42% (boiling) MgCl 2 solution was investigated.

Eusebio Nelson; Dionicio Padilla; Samuel Rosario Francia; Víctor A. Vega Guillen; Oswaldo Gonzales Reynoso; Tabuchi Matsumoto

48

Surface Fatigue Life of Contour Induction Hardened AISI 1552 Gears.  

National Technical Information Service (NTIS)

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and ...

D. P. Townsend A. Turza M. Chaplin

1995-01-01

49

Embrittlement of an AISI 8640 lower bainite steel  

Microsoft Academic Search

A study was performed to determine the cause of an abnormally low fracture toughness of an AISI 8640 resulfurized steel. The embrittlement effects of phosphorus and arsenic on this steel heat-treated to a lower bainitic structure were studied by employing fracture toughness tests, Charpy impact tests, X-ray fluorescent spectroscopy, and scanning electron microscopy (SEM). The results showed that the steel

J. V. Rinnovatore; K. F. Lukens; J. Reinhold; W. Mahon

1993-01-01

50

The characterization of vanadium boride coatings on AISI 8620 steel  

Microsoft Academic Search

Thermodiffusion coatings containing boron and vanadium (B+V) on AISI 8620 steel have been carried out by an initial boronizing in a salt bath consisting of borax, boric acid and ferro-silicon and followed by saturation with vanadium. The properties of the diffusion layer, namely microstructure, phase composition and elemental distribution of the vanadium boride layer, have been studied. The influence of

Saduman Sen

2005-01-01

51

Comparison of Pitting Fatigue Life of Ausforged and Standard Forged AISI M-50 and AISI 9310 Spur Gears.  

National Technical Information Service (NTIS)

Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3.5 in.) in pitch diameter and had tip ...

D. P. Townsend E. N. Bamberger E. V. Zaretsky

1975-01-01

52

Autogenous Laser Keyhole Welding of AISI 316LTi  

Microsoft Academic Search

Effective autogenous full-penetration welding of 4 mm thick AISI 316LTi austenitic stainless steel bars was achieved using a CO2 laser. The welding process parameters required to obtain an optimal and repeatable procedure giving the best quality welds were identified. The use of side jet of gas suppressing plasma formation was investigated, and it was discovered that there are optimal conditions that

Clayton Damato; Maurizio Fenech; Stephen Abela; John C. Betts; Joseph Buhagiar

2010-01-01

53

Kinetics of borided AISI M2 high speed steel  

Microsoft Academic Search

The present study reports on kinetics of borided AISI M2 high speed steel. Boronizing thermochemical treatment was carried out in a solid medium consisting of EKabor powders at 850 °C, 900 °C and 950 °C for 2, 4, 6 and 8 h, respectively. The presence of borides FeB and Fe2B of steel substrate was confirmed by optical microscopy and scanning electron microscopy (SEM). The

I. Ozbek; C. Bindal

54

Corrosion behavior of borided AISI H13 hot work steel  

Microsoft Academic Search

The corrosion behavior of borided hot work steel H13 (AISI) in specific acid solutions (HCl 5 vol.%, H2SO4 5 vol.%, H3PO4 30 vol.%) was studied. Boriding was done by pack cementation. The corrosion behavior was evaluated by potentiodynamic polarization experiments and immersion corrosion tests. The borided steel showed a better corrosion behavior in H2SO4 and H3PO4 environments for short exposure

George K. Kariofillis; Grigoris E. Kiourtsidis; Dimitrios N. Tsipas

2006-01-01

55

Precision radial turning of AISI D2 steel  

Microsoft Academic Search

This paper compares finite element model (FEM) simulations with experimental and analytical findings concerning precision\\u000a radial turning of AISI D2 steel. FEM machining simulation employs a Lagrangian finite element-based machining model applied\\u000a to predict cutting and thrust forces, cutting temperature and plastic strain distribution. The results show that the difference\\u000a between the experimental and simulated cutting force is near 20%,

J. Paulo Davim; C. Maranhão; P. Faria; A. Abrão; J. C. Rubio; Leonardo R. Silva

2009-01-01

56

Corrosion Resistance of Friction Surfaced AISI 304 Stainless Steel Coatings  

NASA Astrophysics Data System (ADS)

Corrosion resistance of friction surfaced AISI 304 coating in boiling nitric acid and chloride containing environments was found to be similar to that of its consumable rod counterpart. This was in contrast to the autogenous fusion zone of GTAW weld which showed inferior corrosion resistance with respect to the consumable rod. The superior corrosion resistance of friction surfaced coatings was attributed to the absence of ?-ferrite in it.

Khalid Rafi, H.; Phanikumar, G.; Prasad Rao, K.

2013-02-01

57

Mechanical properties of boronized AISI W4 steel  

Microsoft Academic Search

A series of experiments was performed to evaluate some mechanical properties of boronized AISI W4 steel. Boronizing was carried out in a solid medium consisting of EKabor powders at 850, 950 and 1050°C for 2, 4, 6 and 8 h. After boronizing, FeB and Fe2B phases were formed on the surface of the steel substrate. A boride layer was revealed

Ibrahim Ozbek; Cuma Bindal

2002-01-01

58

Comparison of pitting fatigue life of ausforged and standard forged AISI M-50 and AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Standard forged and ausforged spur gears made of vacuum-induction-melted, consumable-electrode, vacuum-arc-remelted AISI M-50 steel were tested under conditions that produced fatigue pitting. The gears were 8.89 cm (3.5 in.) in pitch diameter and had tip relief. The M-50 standard forged and ausforged test results were compared with each other. They were then compared with results for machined vacuum-arc-remelted AISI 9310 gears tested under identical conditions. Both types of M-50 gears had lives approximately five times that of the 9310 gears. The life at which 10 percent of the M-50 ausforged gears failed was slightly less than that at which the M-50 standard forged gears failed. The ausforged gears had a slightly greater tendency to fail by tooth fracture than did the standard forged gears, most likely because of the better forging and grain flow pattern of standard forged gears.

Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

1975-01-01

59

Cavitation erosion and corrosion behavior of Ni–Al intermetallic coatings  

Microsoft Academic Search

The high fracture toughness and corrosion resistance of Ni3Al intermetallic material produces good cavitation resistance. To yield Ni–Al coatings on commonly used metals is beneficial in many aspects. A cathodic arc plasma (CAP) ion plating process was demonstrated to deposit Ni–Al film on AISI 1045 carbon steel to evaluate the cavitation protection. Three target materials with Ni52Al48, Ni60Al40, and Ni70Al30

J. T. Chang; C. H. Yeh; J. L. He; K. C. Chen

2003-01-01

60

The growth kinetics of borides formed on boronized AISI 4140 steel  

Microsoft Academic Search

The growth kinetics of boride layer on boronized AISI 4140 steel is reported. Steel samples were boronized in molten borax, boric acid and ferro-silicon bath at 1123, 1173 and 1223K for 2, 4, 6 and 8h, respectively. The morphology and types of borides formed on the surface of AISI 4140 steel substrate were analyzed by means of optical microscopy, scanning

Saduman Sen; Ugur Sen; Cuma Bindal

2005-01-01

61

Stress relaxation in bending of type AISI 304 and A-286 steels at 773 K  

Microsoft Academic Search

Stress relaxation measurements at 773 K, in bending and for different initial stresses, in Type AISI 304 and A-286 steels are reported. Several thermomechanical treatments were given to the specimens prior to the relaxation testing. The data are interpreted in terms of a stress-partitioned power law and it is shown, for AISI 304, that, for certain thermomechanical treatments, the internal

F. Povolo; R. Tinivella

1984-01-01

62

CHROMIUM PLATING FOR PROTECTION AGAINST STRESS CORROSION CRACKING OF HARDENED AISI 410 STEEL  

Microsoft Academic Search

Because of its high corrosion resistance properties, chromium ; electroplate should offer protection to AISI 419 steel against stress corrosion ; cracking. Tests have been made (KAPL and Bettis) on chromium plates on test ; specimens as deposited by two different sources in conformance with Bettis and ; USMC specifications. These deposits either offered protection to hardened (RC36-; 42) AISI

Suss

1958-01-01

63

The Effect of Cryogenic Treatment on the Properties of AISI D2  

Microsoft Academic Search

The tool steel AISI D2 is usually processed by vacuum hardening followed by multiple tempering cycles. Deep cold treatment in between the hardening and tempering processes could reduce processing time and improve the final properties. Blocks of AISI D2 were vacuum hardened from different austenitizing temperatures. The hardened blocks were then subjected to various combinations of single and multiple tempering

C. H. Surberg; P. F. Stratton; K. Lingenhöle

2009-01-01

64

A Life Study of Ausforged, Standard Forged and Standard Machined AISI M-50 Spur Gears.  

National Technical Information Service (NTIS)

Tests were conducted at 350 K (170 F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum induction melted (VIM) consumable-electrode vacuum-arc melted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 ...

D. P. Townsend E. N. Bamberger E. V. Zaretsky

1975-01-01

65

Soldagem Tig de tubos de aco inox AISI 316 para varetas combustiveis. (Tig welding of stainless steel AISI 316 tubes for fuel rods).  

National Technical Information Service (NTIS)

Sealing of austenitic stainless steel AISI 316 tubes (20% cold worked). By welding end-caps material was studied, aiming their utilization as fuel rods for nuclear reactors. It was used the autogenous TIG welding process. (author). (Atomindex citation 25:...

M. Siqueira Queiroz Bittencourt

1985-01-01

66

Crack growth behavior of AISI-4340 steel during environmental exposure  

NASA Technical Reports Server (NTRS)

AISI-4340 is observed to undergo stress corrosion cracking when subjected to a constant load during exposure to a 3.5% NaCl solution. Crack initiation, nucleation, and growth has been monitored as a function of time. Stepped regions consisting of fast and slow crack growth periods are shown to correspond to microstructural changes observed in the fracture surface of the steel. These regions of fast and slow crack rate variations with time show that the crack growth rates do not increase continuously with an increase in the stress intensity.

Giannuzzi, Lucille A.

1995-01-01

67

Oxidation Kinetics of Boronized Low Carbon Steel AISI 1018  

Microsoft Academic Search

The high-temperature oxidation behavior of boron coating on plain low-carbon steel AISI 1018 was studied at 500, 600, 700,\\u000a 800 and 900 °C in air. The oxidation resistance of unboronized (uncoated) and boronized (boron-coated) specimens was studied\\u000a isothermally in a thermogravimetric analyzer. The oxidation-rate constant represented as a parabolic rate constant (k\\u000a \\u000a p\\u000a ) was evaluated with the parabolic rate law.

Naruemon Suwattananont; Roumiana S. Petrova

2008-01-01

68

A study of cumulative fatigue damage in AISI 4130 steel  

NASA Technical Reports Server (NTRS)

Experimental data were obtained using AISI 4130 steel under stress ratios of -1 and 0. A study of cumulative fatigue damage using Miner's and Kramer's equations for stress ratios of -1 and 0 for low-high, low-high-mixed, high-low, and high-low-mixed stress sequences has revealed that there is a close agreement between the theoretical and experimental values of fatigue damage and fatigue life. Kramer's equation predicts less conservative and more realistic cumulative fatigue damage than the popularly used Miner's rule does.

Jeelani, S.; Musial, M.

1986-01-01

69

Formation of titanium aluminum nitride layers on AISI D2 steel by nitro-titanizing treatment  

NASA Astrophysics Data System (ADS)

In this study, titanium aluminum nitride coating was realized on AISI D2 steels by nitro-titanizing treatment. Steel samples were nitrided at 575 °C for 8 h in the first step of the coating process, and then titanized by thermo-reactive diffusion method in the powder mixture consisting of ferro-titanium, aluminum, ammonium chloride and alumina at 1000 °C for 2 h. The effects of the aluminum content to the coating bath were investigated. The thickness of the titanium aluminum nitride layer formed on the steel samples ranged from 6.30+/-0.5 to 7.89+/-0.34?m, depending on the aluminum content. The average micro-hardness value of the layer was 1468 +/- 96 HV0.005 and 2630+/- 83 HV0.005. The phases formed on the coating layers are TiN, AlTi3N and Ti3Al2N2 which are characterized by XRD. EDS analysis results showed that coating layer includes titanium, aluminum and nitrogen.

Cegil, Ozkan; Sen, Saduman

2012-09-01

70

Atomic diffusion in laser surface modified AISI H13 steel  

NASA Astrophysics Data System (ADS)

This paper presents a laser surface modification process of AISI H13 steel using 0.09 and 0.4 mm of laser spot sizes with an aim to increase surface hardness and investigate elements diffusion in laser modified surface. A Rofin DC-015 diffusion-cooled CO2 slab laser was used to process AISI H13 steel samples. Samples of 10 mm diameter were sectioned to 100 mm length in order to process a predefined circumferential area. The parameters selected for examination were laser peak power, pulse repetition frequency (PRF), and overlap percentage. The hardness properties were tested at 981 mN force. Metallographic study and energy dispersive X-ray spectroscopy (EDXS) were performed to observe presence of elements and their distribution in the sample surface. Maximum hardness achieved in the modified surface was 1017 HV0.1. Change of elements composition in the modified layer region was detected in the laser modified samples. Diffusion possibly occurred for C, Cr, Cu, Ni, and S elements. The potential found for increase in surface hardness represents an important method to sustain tooling life. The EDXS findings signify understanding of processing parameters effect on the modified surface composition.

Aqida, S. N.; Brabazon, D.; Naher, S.

2013-07-01

71

Solid-particle erosion of tungsten carbide/cobalt cermet vs. hardened AISI 440C stainless steel.  

SciTech Connect

Solid-particle erosion tests were conducted on hardened AISI 440C stainless steel and a cermet that consisted of {approx}90 vol.% submicrometer WC embedded in {approx}10 vol.% Co. Angular Al{sub 2}O{sub 3} abrasives were used as the erodent. Experimental variables were: angle of impact = 20, 50, or 90 degrees; erodent velocity = 60 or 120 m/s; erodent nominal diameter = 63 or 143 {micro}m. For all test conditions, the stainless steel eroded faster than the cermet. Analysis of weight-loss data and examination of eroded surfaces by scanning electron microscopy indicated that the erosion mechanisms were similar for the two hard materials. Both exhibited significant plasticity when impacted, but the stainless steel's response to impact appeared to have been more ductile in nature.

Rateick, R. G., Jr.; Karasek, K. R.; Cunningham, A.; Goretta, K. C.; Routbort, J. L.; Energy Technology; Honeywell

2006-01-01

72

Texture evolution in thin-sheets on AISI 301 metastable stainless steel under dynamic loading.  

National Technical Information Service (NTIS)

The evolution of texture in thin sheets of metastable austenitic stainless steel AISI 301 is affected by external conditions such as loading rate and temperature, by inhomogeneous deformation phenomena such as twinning and shear band formation, and by the...

K. Y. Kim K. Kozaczek S. M. Kulkarni P. C. Bastias G. T. Hahn

1995-01-01

73

Electrical Resistivity and Thermal Conductivity of Nine Selected AISI Stainless Steels.  

National Technical Information Service (NTIS)

This technical report reviews the available experimental data and information on the electrical resistivity and thermal conductivity of nine selected AISI stainless steels and presents the recommended values from near absolute zero (1 K) to above the melt...

C. Y. Ho T. K. Chu

1977-01-01

74

Rapid machining of hardened AISI H13 and D2 moulds, dies and press tools  

Microsoft Academic Search

Tools and dies for the forging, die casting and plastics moulding industries are commonly made from AISI H13, heat treated to 48–52 HRC, while the press tool sector predominantly uses AISI D2 at a significantly higher hardness of 60–62 HRC. Over the last 10 years, the introduction of high speed end milling has enabled the direct manufacture of prismatic components

Helen Coldwell; Richard Woods; Martin Paul; Philip Koshy; Richard Dewes; David Aspinwall

2003-01-01

75

Enhanced corrosion resistance of AISI H13 steel treated by nitrogen plasma immersion ion implantation  

Microsoft Academic Search

Electrochemical corrosion measurements of AISI H13 steel treated by PIII process in 3.5% (wt) NaCl solution were investigated. So far the corrosion behavior of AISI H13 steel by PIII has not been studied. The electrochemical results are correlated with the surface morphology, nitrogen content and hardness of the nitride layer. Ion implantation of nitrogen into H13 steel was carried out

L. L. G. da Silva; M. Ueda; R. Z. Nakazato

2007-01-01

76

Texture evolution in thin-sheets on AISI 301 metastable stainless steel under dynamic loading  

SciTech Connect

The evolution of texture in thin sheets of metastable austenitic stainless steel AISI 301 is affected by external conditions such as loading rate and temperature, by inhomogeneous deformation phenomena such as twinning and shear band formation, and by the concurent strain induced phase transformation of the retained austenitc ({gamma}) into martensite ({alpha}). The present paper describes texture measurements on different gauges of AISI 301 prior and after uniaxial stretching under different conditions.

Kim, K.Y. [Posco Steels, Pohan, South Korea (Korea, Republic of); Kozaczek, K. [Oak Ridge National Lab., TN (United States); Kulkarni, S.M. [TRW Vehicle Safety Systems, Mesa, AZ (United States); Bastias, P.C.; Hahn, G.T. [Vanderbilt Univ., Nashville, TN (United States)

1995-05-08

77

Effect of Cryogenic Treatment on AISI M2 High Speed Steel: Metallurgical and Mechanical Characterization  

Microsoft Academic Search

This study aims to present the metallurgical and mechanical characterization of cryogenically treated AISI M2 high speed steel\\u000a (HSS) in terms of carbide precipitation and wear behavior. The samples of commercially available conventionally quenched and\\u000a tempered AISI M2 HSS were procured and subjected to cryogenic treatment at two levels ?110 °C (shallow treatment) and ?196 °C\\u000a (deep treatment) of temperature. The microstructures

Simranpreet Singh Gill; Jagdev Singh; Rupinder Singh; Harpreet Singh

2011-01-01

78

The effect of boronizing and boro-chromizing on tribological performance of AISI 52100 bearing steels  

Microsoft Academic Search

Purpose – The purpose of this paper is to study the tribological behavior of hardened, boronized and boro-chromized AISI 52100 steel balls against boro-chromized AISI 1040 steel disk under 2, 5 and 10 N loads at 0.1 and 0.3 m\\/s sliding speeds. Design\\/methodology\\/approach – Boronizing treatment was realized at 1,000°C for 2 h in a slurry salt bath consisting of

Saduman Sen; Ugur Sen

2009-01-01

79

Investigation of Boronizing Kinetics of AISI 51100 Steel  

NASA Astrophysics Data System (ADS)

In this study, some mechanical properties of borided AISI 51100 steel with high C concentration were investigated. Boronizing heat treatment was carried out in solid medium consisting of Ekabor-II at 850, 900, and 950 °C for 2, 4, 6, and 8 h. Morphology and mechanical properties of boride layer, and the effect of chemical composition on properties and kinetics of borides were investigated. The results of this study indicated that the morphology of the boride layer has a saw-tooth nature, and its hardness is over 1500 HV. Depending on process time and temperature, the depth of boride layer ranged from 30 to 106 ?m. Optical and SEM studies and XRD analysis revealed that borides formed on the surface of steel substrates have dominantly single Fe2B boride phase in addition to small amount of Cr2B.

Ipek, M.; Celebi Efe, G.; Ozbek, I.; Zeytin, S.; Bindal, C.

2012-05-01

80

Residual Stress Analysis of Boronized AISI 1018 Steel  

SciTech Connect

AISI 1018 steel substrates were powder-pack, diffusion boronized at 850 C for 4 h, followed by air quenching. Optical microscopy in conjunction with color etching was used to obtain the average penetration depth of the iron monoboride layer (9 {mu}m) and the iron diboride layer (57 {mu}m). X-ray diffraction by synchrotron radiation, conducted at the National Synchrotron Light Source in Brookhaven National Laboratory, confirmed the presence of iron monoboride and iron diboride in the boronized plain steel substrates. The sin2 {psi} technique was employed to calculate the residual stress found in the iron monoboride layer (-237 MPa) and in the substrate layer (-150 MPa) that is intertwined with the needle-like, iron diboride penetration.

Payne,J.; Petrova, R.; White, H.; Chauhan, A.; Bai, J.

2008-01-01

81

Embrittlement of an AISI 8640 lower bainite steel  

SciTech Connect

A study was performed to determine the cause of an abnormally low fracture toughness of an AISI 8640 resulfurized steel. The embrittlement effects of phosphorus and arsenic on this steel heat-treated to a lower bainitic structure were studied by employing fracture toughness tests, Charpy impact tests, X-ray fluorescent spectroscopy, and scanning electron microscopy (SEM). The results showed that the steel was embrittled by phosphorus at prior austenite grain boundaries in a manner similar to the tempered martensite embrittlement (TME) phenomenon. Arsenic is also believed to be involved in the embrittlement effect, specifically as related to producing a reduction in the upper shelf Charpy impact energy. Embrittlement was manifested by a reduced fracture toughness, an increase in the Charpy transition temperature, and intergranular fracture.

Rinnovatore, J.V. (MTA, Inc., Mt. Arlington, NJ (United States). Development and Engineering Center); Lukens, K.F.; Reinhold, J.; Mahon, W. (Army Armament Research, Picatinny Arsenal, NJ (United States). Development and Engineering Center)

1993-09-01

82

Fretting of AISI 9310 and selected fretting resistant surface treatments  

NASA Technical Reports Server (NTRS)

Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, alumimum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a self-lubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

Bill, R. C.

1977-01-01

83

Fretting of AISI 9310 and selected fretting resistant surface treatments  

NASA Technical Reports Server (NTRS)

Fretting wear experiments were conducted with uncoated AISI 9310 mating surfaces, and with combinations incorporating a selected coating to one of the mating surfaces. Wear measurements and SEM observations indicated that surface fatigue, as made evident by spallation and surface crack formation, is an important mechanism in promoting fretting wear to uncoated 9310. Increasing humidity resulted in accelerated fretting, and a very noticeable difference in nature of the fretting debris. Of the coatings evaluated, aluminum bronze with a polyester additive was most effective at reducing wear and minimizing fretting damage to the mating uncoated surface, by means of a selflubricating film that developed on the fretting surfaces. Chromium plate performed as an effective protective coating, itself resisting fretting and not accelerating damage to the uncoated surface.

Bill, R. C.

1977-01-01

84

A Life Study of Ausforged, Standard Forged and Standard Machined AISI M-50 Spur Gears  

NASA Technical Reports Server (NTRS)

Tests were conducted at 350 K (170 F) with three groups of 8.9 cm (3.5 in.) pitch diameter spur gears made of vacuum induction melted (VIM) consumable-electrode vacuum-arc melted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears, but the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

Townsend, D. P.; Bamberger, E. N.; Zaretsky, E. V.

1975-01-01

85

A life study of ausforged, standard forged, and standard machined AISI M-50 spur gears  

NASA Technical Reports Server (NTRS)

Tests were conducted at 350 K with three groups of 8.9 cm pitch diameter spur gears made of vacuum-induction melted (VIM), vacuum-arc remelted (VAR), AISI M-50 steel and one group of vacuum-arc remelted (VAR) AISI 9310 steel. The pitting fatigue life of the standard forged and ausforged gears was approximately five times that of the VAR AISI 9310 gears and ten times that of the bending fatigue life of the standard machined VIM-VAR AISI M-50 gears run under identical conditions. There was a slight decrease in the 10-percent life of the ausforged gears from that for the standard forged gears. However, the difference is not statistically significant. The standard machined gears failed primarily by gear tooth fracture while the forged and ausforged VIM-VAR AISI M-50 and the VAR AISI 9310 gears failed primarily by surface pitting fatigue. The ausforged gears had a slightly greater tendency to fail by tooth fracture than the standard forged gears.

Townsend, D. P.; Zaretsky, E. V.; Bamberger, E. N.

1975-01-01

86

Improvement of the Electrochemical Behavior of Steel Surfaces Using a [Ti-Al/Ti-Al-N] n Multilayer System  

NASA Astrophysics Data System (ADS)

The aim of this work is to improve the corrosion resistance of AISI D3 steel surfaces using a [Ti-Al/Ti-Al-N] n multilayer system deposited with different periods (?) and bilayer numbers ( n), via magnetron co-sputtering pulsed d.c. procedure, from a metallic (Ti-Al) binary target. The multilayer coatings were characterized by cross-sectional scanning electron microscopy that showed the modulation and microstructure of the [Ti-Al/Ti-Al-N] n multilayer system. The composition of the single Ti-Al and Ti-Al-N layer films was studied via x-ray photoelectron spectroscopy, where typical signals for Ti2p1/2, Ti2p, N1s, and Al2p3/2 were detected. The electrochemical properties were evaluated by electrochemical impedance spectroscopy and Tafel polarization curves. The optimal electrochemical behavior was obtained for the [Ti-Al/Ti-Al-N] n multilayered period of ? = 25 nm (100 bilayers). At these conditions, the maximum polarization resistance (1719.32 k? cm2) and corrosion rate (0.7 ?my) were 300 and 35 times higher than that of uncoated AISI D3 steel substrate (5.61 k? cm2 and 25 ?my, respectively). Finally, scanning electron microscopy was used to analyze the [Ti-Al/Ti-Al-N] n multilayered surface after the corrosive attack. The improvement effects in the electrochemical behavior of the AISI D3 coated with the [Ti-Al/Ti-Al-N] n multilayered coatings could be attributed to the number of interfaces that act as obstacles for the inward and outward diffusions of Cl- ions, generating an increment in the energy or potential required for translating the corrosive ions across the coating/substrate interface.

Ipaz, L.; Aperador, W.; Caicedo, J. C.; Esteve, J.; Zambrano, G.

2013-05-01

87

The effect of annealing on properties of AISI 316L base and weld metals Vpliv žarjenja na lastnosti osnovnega materiala in vara jekla AISI 316L  

Microsoft Academic Search

Results of mechanical testing and of microstructural analysis of AISI 316L austenitic stainless steel carried out before and after welding and post-weld heat treatment are presented. Steel plates of 15 mm thickness were welded by manual electric arc welding process. Heat treatment con- sisted of annealing at 600, 700, 800, and 900 °C for two hours, and was followed by

Stjepan K ožuh; L adis L av K

88

The surface fatigue life of contour induction hardened AISI 1552 gears  

NASA Astrophysics Data System (ADS)

Two groups of spur gears manufactured from two different materials and heat treatments were endurance tested for surface fatigue life. One group was manufactured from AISI 1552 and was finished ground to a 0.4 micron (16 micro-in.) rms surface finish and then dual frequency contour induction hardened. The second group was manufactured from CEVM AISI 9310 and was carburized, hardened, and ground to a 0.4 micron (16 micro-in.) rms surface finish. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a maximum Hertz stress of 1.71 GPa (248 ksi), a bulk gear temperature of approximately 350 K (170 F) and a speed of 10,000 rpm. The lubricant used for the tests was a synthetic paraffinic oil with an additive package. The test results showed that the 10 percent surface fatigue (pitting) life of the contour hardened AISI 1552 test gears was 1.7 times that of the carburized and hardened AISI 9310 test gears. Also there were two early failures of the AISI 1552 gears by bending fatigue.

Townsend, Dennis P.; Turza, Alan; Chaplin, Mike

1995-07-01

89

Effect of cutting edge geometry and workpiece hardness on surface generation in the finish hard turning of AISI 52100 steel  

Microsoft Academic Search

An experimental investigation was conducted to determine the effects of tool cutting edge geometry and workpiece hardness on the surface roughness and cutting forces in the finish hard turning of AISI 52100 steel. Cubic boron nitride inserts with various representative cutting edge preparations and through-hardened AISI 52100 steel bars were used as the cutting tools and workpiece material, respectively. This

Jeffrey D Thiele; Shreyes N. Melkote

1999-01-01

90

AISI and DOE collaborate on Advanced Process Control Program  

SciTech Connect

In today's steel marketplace with its excess capacity and low prices, a high-quality product is no assurance of success. Competition and survival depend on a high-quality product produced at the lowest possible cost. All steel producers are faced with this challenge. To meet that challenge, the American Iron and Steel Institute (AISI) the Dept. of Energy (DOE) are undertaking a nationwide technology research program. In 1988, Congress passed the Steel and Aluminum Energy Conservation and Technology Competitiveness Act. This legislation, called Metals Initiative, managed by the DOE, allocates funding for technical research programs that bring about competitive advantage and energy savings in US metals industries. The six projects which make-up Advanced Process Control are diverse, and deal with specific quality issues, and with the more fundamental task of the intelligent and lowest cost production of a quality product. Brief descriptions are given of the six projects: optical sensors and control for improved BOF operation; improved liquid steel feeding for slab casters; microstructure engineering in hot strip mills; on-line, nondestructive mechanical properties measurements using magnetic and ultrasonic techniques; phase measurement of galvanneal; and temperature measurement of galvanneal.

Kavanagh, L.W. (American Iron and Steel Inst., Monroeville, PA (United States))

1993-05-01

91

AISI waste oxide recycling program. Final technical report  

SciTech Connect

In March 1995 AISI completed a five-year, $60 million collaborative development program on Direct Steelmaking cost-shared by DOE under the Metals Initiative. This program defined an energy-efficient and environmentally-friendly technology to produce hot metal for steelmaking directly from coal and iron ore pellets without incurring the high capital costs and environmental problems associated with traditional coke oven and blast furnace technology. As it becomes necessary to replace present capacity, this new technology will be favored because of reduced capital costs, higher energy efficiency, and lower operating costs. In April 1994, having failed to move forward with a demonstration plant for direct ironmaking, despite substantial efforts by both Stelco and Geneva Steel, an alternative opportunity was sought to commercialize this new technology without waiting until existing ironmaking capacity needed to be replaced. Recycling and resource recovery of steel plant waste oxides was considered an attractive possibility. This led to approval of a ten-month, $8.3 million joint program with DOE on recycling steel plant waste oxides utilizing this new smelting technology. This highly successful trial program was completed in December 1994. The results of the pilot plant work and a feasibility study for a recycling demonstration plant are presented in this final technical report.

Aukrust, E.; Downing, K.B.; Sarma, B.

1995-08-01

92

The Forming of AISI 409 sheets for fan blade manufacturing  

SciTech Connect

The necessity of adapting the standardized fan models to conditions of higher temperature has emerged due to the growth of concern referring to the consequences of the gas expelling after the Mont Blanc tunnel accident in Italy and France, where even though, with 100 fans in operation, 41 people died. The objective of this work is to present an alternative to the market standard fans considering a new technology in constructing blades. This new technology introduces the use of the stainless steel AISI 409 due to its good to temperatures of gas exhaust from tunnels in fire situation. The innovation is centered in the process of a deep drawing of metallic sheets in order to keep the ideal aerodynamic superficies for the fan ideal performance. Through the impression of circles on the sheet plane it is shown, experimentally, that, during the pressing process, the more deformed regions on the sheet plane of the blade can not reach the deformation limits of the utilized sheet material.

Foroni, F. D.; Menezes, M. A.; Moreira Filho, L. A. [ITA - Aeronautic Technological Institute, IEM, Praca Mal. Eduardo Gomes, 50 - Vila das Acacias - S. J. Campos, Brasil - CEP 1228-900 (Brazil)

2007-04-07

93

Hot compression deformation behavior of AISI 321 austenitic stainless steel  

NASA Astrophysics Data System (ADS)

The hot compression behavior of AISI 321 austenitic stainless steel was studied at the temperatures of 950-1100°C and the strain rates of 0.01-1 s-1 using a Baehr DIL-805 deformation dilatometer. The hot deformation equations and the relationship between hot deformation parameters were obtained. It is found that strain rate and deformation temperature significantly influence the flow stress behavior of the steel. The work hardening rate and the peak value of flow stress increase with the decrease of deformation temperature and the increase of strain rate. In addition, the activation energy of deformation ( Q) is calculated as 433.343 kJ/mol. The microstructural evolution during deformation indicates that, at the temperature of 950°C and the strain rate of 0.01 s-1, small circle-like precipitates form along grain boundaries; but at the temperatures above 950°C, the dissolution of such precipitates occurs. Energy-dispersive X-ray analyses indicate that the precipitates are complex carbides of Cr, Fe, Mn, Ni, and Ti.

Haj, Mehdi; Mansouri, Hojjatollah; Vafaei, Reza; Ebrahimi, Golam Reza; Kanani, Ali

2013-06-01

94

Microstructure, oxidation and H 2-permeation resistance of TiAlN films deposited by DC magnetron sputtering technique  

Microsoft Academic Search

The ternary compound TiAlN coating has been known to be superior to binary compound TiN in protecting tools, which may be damaged by high thermal load. In the present study, TiAlN coatings are deposited on stainless (AISI 316L) and carbon steel substrates by using DC sputtering technique. The structure of TiAlN coatings with different Al contents is studied using X-ray

B. Y. Man; L. Guzman; A. Miotello; M. Adami

2004-01-01

95

Dependence on displacement rate of radiation-induced changes in microstructure and tensile properties of AISI 304 and 316  

SciTech Connect

Annealed specimens of AISI 304 and 316 were irradiated in the EBR-II fast reactor at approx. 400/sup 0/C over a range of neutron fluxes and energy spectra. Tensile tests show that the hardening of the AISI 304 is sensitive to the displacement rate while the hardening of AISI 316 is not. However, the microstructures of both AISI 304 and 316 are influenced by displacement rate. The increase in yield strength of the specimens is correlated with the contribution of the various microstructural components produced during irradiation. The insensitivity in the hardening of AISI 316 to displacement rate arises because the strengthening contribution from precipitates increases with displacement rate, whereas the strengthening contribution from voids decreases.

Brager, H.R.; Blackburn, L.D.; Greenslade, D.L.

1983-08-01

96

Effect of Cryogenic Treatment on AISI M2 High Speed Steel: Metallurgical and Mechanical Characterization  

NASA Astrophysics Data System (ADS)

This study aims to present the metallurgical and mechanical characterization of cryogenically treated AISI M2 high speed steel (HSS) in terms of carbide precipitation and wear behavior. The samples of commercially available conventionally quenched and tempered AISI M2 HSS were procured and subjected to cryogenic treatment at two levels -110 °C (shallow treatment) and -196 °C (deep treatment) of temperature. The microstructures obtained after cryogenic treatments have been characterized with a prominence to comprehend the influence of cryogenic treatment vis-à-vis conventional quenching and tempering on the nature, size, and distribution of carbides. The mechanical properties such as hardness and wear rate of the specimens have also been compared by performing Rockwell C hardness test and pin-on-disc wear test, respectively. Microstructures, hardness, wear rate and analysis of worn surface reveal the underlying metallurgical mechanism responsible for the improving mechanical properties of the AISI M2 HSS.

Gill, Simranpreet Singh; Singh, Jagdev; Singh, Rupinder; Singh, Harpreet

2012-07-01

97

Surface fatigue life of CBN and vitreous ground carburized and hardened AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Spur gear surface endurance tests were conducted to investigate CBN ground AISI 9310 spur gears for use in aircraft applications, to determine their endurance characteristics and to compare the results with the endurance of standard vitreous ground AISI 9310 spur gears. Tests were conducted with VIM-VAR AISI 9310 carburized and hardened gears that were finish ground with either CBN or vitreous grinding methods. Test conditions were an inlet oil temeprature of 320 K (116 F), an outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. The CBN ground gears exhibited a surface fatigue life that was slightly better than the vitreous ground gears. The subsurface residual stress of the CBN ground gears was approximately the same as that for the standard vitreous ground gears for the CBN grinding method used.

Townsend, Dennis P.; Patel, P. R.

1988-01-01

98

Endurance and failure characteristics of modified Vasco X-2, CBS 600 and AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Gear endurance tests and rolling-element fatigue tests were conducted to compare the performance of spur gears made from AISI 9310, CBS 600 and modified Vasco X-2 and to compare the pitting fatigue lives of these three materials. Gears manufactured from CBS 600 exhibited lives longer than those manufactured from AISI 9310. However, rolling-element fatigue tests resulted in statistically equivalent lives. Modified Vasco X-2 exhibited statistically equivalent lives to AISI 9310. CBS 600 and modified Vasco X-2 gears exhibited the potential of tooth fracture occurring at a tooth surface fatigue pit. Case carburization of all gear surfaces for the modified Vasco X-2 gears results in fracture at the tips of the gears.

Townsend, D. P.; Zaretsky, E. V.

1980-01-01

99

Coupled Multi-Electrode Investigation of Crevice Corrosion of AISI 316 Stainless Steel  

SciTech Connect

Close packed coupled multi-electrodes arrays (MEA) simulating a planar electrode were used to measure the current evolution as a function of position during initiation and propagation of crevice corrosion of AISI 316 stainless steel. Scaling laws derived from polarization data enabled the use of rescaled crevices providing spatial resolution. Crevice corrosion of AISI 316 stainless steel in 0.6 M NaCl at 50 C was found to initiate close to the crevice mouth and to spread inwards with time. The local crevice current density increased dramatically over a short period to reach a limiting value.

F. Bocher; F. Presuel-Moreno; N.D. Budinasky; J.R. Scully

2006-06-23

100

Rolling Contact Fatigue Life and Spall Propagation of AISI M50, M50NiL, and AISI 52100, Part II: Stress Modeling  

Microsoft Academic Search

This is the second part of a three-part series that investigates the rolling contact fatigue initiation and spall propagation characteristics of three bearing materials, namely, AISI 52100, VIM-VAR M50, and VIM-VAR M50NiL steels. A systematic investigation of the effects of rolling contact fatigue (RCF) on the evolution of material properties and microstructural changes resulting in spall propagation rate has not

Nagaraj K. Arakere; Nathan Branch; George Levesque; Vaughn Svendsen; Nelson H. Forster

2009-01-01

101

Finite element modeling of the formation of adiabatic shear bands in AISI 4340 steel  

Microsoft Academic Search

Adiabatic shear bands (ASB) occur during the plastic deformation of metals at high strain rates in torsional split-Hopkinson bar tests. The formation of ASB in AISI 4340 steel was modeled using the finite element (FE) method. Both strain hardening and thermal softening were considered and attention was given to the initialization and growth of the ASB. The calculated results indicate

H Feng; M. N Bassim

1999-01-01

102

Hydrogen embrittlement in an AISI 1045 steel component of the sugarcane industry  

Microsoft Academic Search

This paper will present a failure analysis of a chain component, manufactured with AISI 1045 steel and used for sugarcane transport. During the fabrication process, this component is submitted to induction hardening, just on one surface, before the galvanizing process. The occurrence of surface cracks, during storage, disables the usage of these components. Chemical and metallographic analyses, tensile, fracture toughness,

A. L. Marcelo; R. C. Tokimatsu; I. Ferreira

2009-01-01

103

The inhibition of corrosion and hydrogen embrittlement of AISI 410 stainless steel  

Microsoft Academic Search

A study was carried out on the inhibition of corrosion and hydrogen embrittlement of AISI 410 stainless steel by two organic inhibitors, namely benzotriazole and benzonitrile. Tensile testing, scanning electron microscopy, weight loss measurements and potentiodynamic polarization were the techniques used for this study. Tensile tests showed that 410 steel is highly susceptible to hydrogen stress cracking. Scanning electron microscopic

R. Agrawal; T. K. G. Namboodhiri

1992-01-01

104

Inhibition of hydrogen embrittlement in high strength steel. Technical report. [AISI 4340  

Microsoft Academic Search

The addition of rare earth gettering agents to trap hydrogen was evaluated as a method of reducing the embrittlement problems in steel cathodically charged with hydrogen. Additions of lanthanum and cerium made to AISI 4340 steel were used in the 0.03--0.17 weight percent range. Mechanical property results were comparable for both elements and indicated that, while some degradation in property

Kortovich

1977-01-01

105

Aspects of Plasma Arc Cutting Process in the AISI 321 Type Stainless Steel.  

National Technical Information Service (NTIS)

Some aspects of plasma arc cutting process in the AISI321 stainless steel, used in nuclear industry, are analysed. The maximum values of the velocity of cutting and, the minimum quantity of energy per unit of length necesary for the plasma were determined...

I. Souza Barros

1985-01-01

106

Caracterización por Difracción de Rayos X de un Acero Inoxidable AISI 304 Nitrurado por Plasma  

Microsoft Academic Search

AISI 304 stainless steel samples have been ion nitrided using a DC pulsed plasma under differents conditions of temperature, current density and nitrogen partial pressure of N2-H2. X-Ray Diffraction (XRD) was used for characterization of the nitrided layer, which consists essentially of an expanded austenite structure or \\

S. P. Brühl; N. Mingolo

2005-01-01

107

Effect of Niobium on Microstructure of Cast AISI H13 Hot Work Tool Steel  

Microsoft Academic Search

The effect of niobium addition on the microstructure of cast AISI H13 hot work tool steel was evaluated by using EDX analyzer attached to the scanning electron microscope. The volume percent of eutectic area and eutectic cell size and also volume percent of different carbides of new steel, which is heat treated under different conditions, are also determined. The results

Shahram Kheirandish; Ahmad Noorian

2008-01-01

108

Microstructure effects on the thermal properties of vacuum sintered AISI 316L stainless steel  

Microsoft Academic Search

The photothermal technique open photoacoustic cell and the non-Adiabatic thermal relaxation calorimetric are applied to measure thermal properties of the sintered stainless steel AISI 316L as a function of the porosity. The results showed that thermal diffusivity and thermal conductivity values as a function of the applied uniaxial pressure presented a strong correlation with the surface area of contact of

W. M. Lima; W. R. Weinand; V. Biondo; E. S. Nogueira; A. N. Medina; M. L. Baesso; A. C. Bento

2003-01-01

109

Measurement of the thermal expansion coefficient of AISI 420 stainless steel between 20 and 293 K  

NASA Astrophysics Data System (ADS)

The accurate measurement of thermal expansion coefficient at low temperatures is fundamental in applications where a high mechanical stability is required over the complete procedure of cooling. Here we report on our measurement of thermal expansion of AISI 420 between 20 and 293 K, measured by an interferometric dilatometer.

Martelli, Valentina; Bianchini, Giovanni; Ventura, Guglielmo

2014-07-01

110

Effects of hydrogen charging methods on ductility and fracture characteristics of AISI 9840 steel  

Microsoft Academic Search

Two different methods were used in the tests: the premature fracture method and the tensile test under hydrogen charging method, on AISI 9840 steel stress-corrosion specimens. The aim of this work was to reveal the hydrogen effects on plastic deformation in tensile tests with or without simultaneous hydrogen charging. True stress-true strain curves have clearly shown the material's different behaviour

G. Biggiero; A. Borruto; I. Taraschi

1995-01-01

111

Variation in sessile microflora during biofilm formation on AISI304 stainless steel coupons  

Microsoft Academic Search

Coupons of stainless steel type AISI-304 were exposed to the industrial cooling system of a petrochemical plant fed by seawater from the Guanabara Bay, Rio de Janeiro, Brazil, in order to study thein situ formation of biofilms. Bacteria, microalgae and fungi were detected on the coupons as soon as 48 h after exposure. Their respective numbers were determined at times

F P de França; M T S Lutterbach

1996-01-01

112

Continuous Drive Friction Welding Studies on AISI 304 Austenitic Stainless Steel Welds  

Microsoft Academic Search

An attempt has been made to study the friction welding characteristics of an austenitic stainless steel AISI 304 employing a continuous drive friction welding machine. The central region in some of the welds exhibited abnormal grain growth. Optimization studies revealed that the optimum parameters depend on the property of interest. In general, friction welds exhibited lower notch tensile strength and

V. V. Satyanarayana; G. Madhusudhan Reddy; T. Mohandas

2004-01-01

113

An investigation into joining of austenitic-stainless steels (AISI 304) with friction welding  

Microsoft Academic Search

Purpose – Aims to determine if friction welding is suitable for welding austenitic stainless steel (AISI 304) Design\\/methodology\\/approach – Uses an experimental continuous drive friction welding set-up. Determined the strength, hardness and microstructure of the joined parts. Findings – Finds that the joint strengths are 96 per cent of those of the base metals with no significant hardening. Practical implications

Mumin Sahin

2005-01-01

114

Research on wear characteristics of AISI 1035 steel boronized at various parameters  

Microsoft Academic Search

Purpose – This paper aims to research the tribological features of AISI 1035 steel, boronized at various parameters. Design\\/methodology\\/approach – The samples were boronized via box boronizing method. By using Ekabor 2 powders, boronizing was conducted at 840, 880, 920, 960 and 1,000°C for two, four and six hours. Wear resistance of boronized samples at determined parameters were analysed. Wear

N. Kiratli; F. Findik

2011-01-01

115

BORLANMIAISI 1040 ÇEL ??? NN TRBOLOJK ÖZELLKLERNN ?NCELENMES ? INVESTIGATION OF TRIBOLOGICAL PROPERTIES OF BORONIZED AISI 1040 STEEL  

Microsoft Academic Search

In this paper, the tribological properties of AISI 1040 steel were researched. Samples were boronized in temperatures of 820°C, 860°C, 900°C in 2, 4 and 6 hour using Ekabor 2 powders by packed boriding method. Phases and depth of boronized samples were determined via microstructure analyses. Hardness distribution was detected depending on depth from surface. Tribological behaviours of boronizing samples

Simge GENÇALP

116

AISI direct steelmaking program. Annual technical report for year ending November 30, 1990.  

National Technical Information Service (NTIS)

AISI with co-funding from DOE has initiated a research and development program aimed at the development of a new process for direct steelmaking, and the program is discussed in this document. The project is expected to cost about $30 million over a three-...

E. Aukrust

1991-01-01

117

Microstructue and mechanical properties of AISI 4340 steel modified with aluminum and silicon  

Microsoft Academic Search

The influence of additions of aluminum and combinations of aluminum and silicon to AISI 4340 steels was investigated. The mechanical properties such as strength, fracture toughness (K\\/sub Ic\\/), and impact toughness (C\\/sub v\\/) were obtained for the modified steels in the quenched and tempered condition. The microstructure was characterized using optical and transmission electron microscopy. The fracture surfaces and inclusions

Bhat

1977-01-01

118

Effects of silicon on structures and properties of AISI 4320 low alloy steel  

Microsoft Academic Search

The effects of 2 percent silicon addition on the structures and properties in AISI 4320 steel were studied; transmission electron microscopy was extensively used to characterize the microstructures. In as-quenched and tempered martensite, silicon additions increase the temperature range in which epsilon carbide exists, delay the cementite precipitation and retained austenite decomposition to higher temperatures. The silicon addition increases the

1975-01-01

119

Machining of AISI 316 Stainless Steel Under CarbonDioxide Cooling  

Microsoft Academic Search

This work investigates the effect of carbon dioxide (CO2) as the cutting fluid in turning AISI 316 stainless steel work material on cutting temperature, cutting force, tool wear, surface roughness and chip morphology when compared to dry and wet machining. Compared to wet machining, in CO2 machining the cutting temperature was reduced up to 35% and the surface finish of

B. Dilip Jerold; M. Pradeep Kumar

2012-01-01

120

Fatigue properties of an AISI 1045 steel coated with an electroless NiP deposit  

Microsoft Academic Search

The fatigue behavior of samples of an AISI 1045 steel plated with electroless Ni-P (EN) deposits, both on an industrial and laboratory scale, has been evaluated under completed reverse bending or rotating bending conditions. The fatigue experiments were conducted in air at a frequency of 50 Hz, in the stress range of 292–346 MPa. On the laboratory scale, the deposition

G. Contreras; C. Fajardo; J. A. Berr??os; A. Pertuz; J. Chitty; H. Hintermann; E. S. Puchi

1999-01-01

121

Microstructure development in Nd:YAG laser welding of AISI 304 and Inconel 600  

Microsoft Academic Search

In this work, the morphology of solidification of the weld zone (WZ) was studied in a joint formed from dissimilar materials, composed of austenitic AISI 304 stainless steel and Inconel 600 nickel alloy, welded with an Nd:YAG-pulsed laser. The laser beam and optical system parameters were selected with a view to obtain a weld with total penetration and good surface

Maurício David M. das Neves; André Lotto; José Roberto Berretta; Wagner de Rossi; Nilson Dias V. Júnior

2010-01-01

122

Mechanisms of Environment Induced Subcritical Flaw Growth in AISI 4340 Steel.  

National Technical Information Service (NTIS)

An experiment designed to study the effect of several variables on the subcritical crack growth rate of a high-strength steel in a water environment was conducted. Double cantilever beam specimens of an AISI 4340 steel were employed to study crack extensi...

H. T. Corten W. A. Van Der Sluys

1966-01-01

123

Analysis of first order kinetics for tertiary creep in AISI 304 stainless steel  

Microsoft Academic Search

The results of constant load creep tests on AISI 304 stainless steel at 873 and 973 K for different test conditions were found to obey the first order kinetics for tertiary creep. Distinct master creep curves were obtained at 873 and 973 K with a separate set of constant values of K?, ?t, ?? and CMG. A relationship between steady-state

C. Phaniraj; M. Nandagopal; S. L. Mannan; P. Rodriguez; B. P. Kashyap

1996-01-01

124

The direct laser deposition of AISI316 stainless steel and Cr 3C 2 powder  

Microsoft Academic Search

The laser deposition of AISI316 powder blended with Cr3C2 over austenitic stainless steel plate was carried out as part of an investigation aimed at determining the feasibility of applying localized reinforcement to stainless steel components. The chromium carbide powder dissolved in the process to produce a range of carbides which reinforced and increased the hardness of the material. The results

John C. Betts

2009-01-01

125

Precipitation of carbides and sigma phase in AISI type 446 stainless steel under working conditions  

Microsoft Academic Search

The microstructure of tubes of AISI 446 ferritic stainless steels used in a heating furnace of a petrochemical plant was investigated using scanning electron microscopy, energy-dispersive spectrometry, X-ray diffraction, hardness and microhardness measurements. It was found that, under the working conditions the tubes were subjected, precipitation of carbides and sigma phase occurs. Heat treatment does dissolve these precipitates but the

A. A. Guimarães; P. R. Mei

2004-01-01

126

Fabrication of spectrally selective solar surfaces by the thermal treatment of austenitic stainless steel aisi 321  

Microsoft Academic Search

The spectrally selective solar surfaces have been produced after heating the austenitic stainless steel aisi 321 at a firing temperature of 843* K. And for firing times ranging from 10 to 20 minutes. The heating was carried out in a constant temperature oven under normal atmospheric conditions. The optimum values of solar absorptance alpha S and near-normal emittance epsilon S

1981-01-01

127

Fatigue life extension of notches in AISI 304L weldments using deep cryogenic treatment  

Microsoft Academic Search

The fatigue crack initiation lives of notches in AISI 304L austenitic stainless steel weldments were improved after the deep cryogenic treatment of specimens at liquid nitrogen temperature (?185 °C). During this treatment, a significant change in microstructure is developed. Strain induced martensitic transformation occurs. During this transformation, the weld metal expands. This expansion relieves the tensile residual stresses and induces

P. Johan Singh; S. L. Mannan; T. Jayakumar; D. R. G. Achar

2005-01-01

128

Fatigue life improvement of AISI 304L cruciform welded joints by cryogenic treatment  

Microsoft Academic Search

Existing theories and reported practical experience show that cryogenic processing greatly increases abrasion resistance and contact fatigue resistance of some metals and alloys. In the present work, an attempt has been made to investigate the effect of cryogenic treatment on the axial fatigue performance of fillet welded cruciform joints of AISI 304L stainless steel, which failed in the weld metal.

P Johan Singh; B Guha; D. R. G Achar

2003-01-01

129

Sub-zero treatments of AISI D2 steel: Part II. Wear behavior  

Microsoft Academic Search

Wear behavior of AISI D2 steel specimens subjected to varied sub-zero treatments, namely: cold treatment, shallow cryogenic treatment and deep cryogenic treatment have been studied with respect to that of the conventionally heat treated ones. The wear behavior has been assessed by dry sliding wear tests under varying normal loads as well as by detailed characterizations of worn surfaces, subsurfaces

Debdulal Das; Apurba Kishore Dutta; Kalyan Kumar Ray

2010-01-01

130

Deep cryogenic treatment of AISI 302 stainless steel: Part I – Hardness and tensile properties  

Microsoft Academic Search

The effects of deep cryogenic treatment (DCT) on the static mechanical properties of the AISI 302 austenitic stainless steel were investigated through experimental testing. The results of the tensile and hardness tests are discussed and compared to data and microstructural observations from the DCT literature concerning the same class of steel. In addition, the influence of two important treatment parameters,

Paolo Baldissera

2010-01-01

131

Mechanical properties of duplex layer formed on AISI 403 stainless steel by chromizing and boronizing treatment  

Microsoft Academic Search

In order to improve the high temperature performance of AISI 403 martensitic stainless steel, duplex surface treatment which combines the methods of pack cementation chromizing and boronizing was carried out. Specimens were chromized at 1100 °C for 2 h and were subsequently boronized in a solid medium consisting of EKabor-III powders at 950 °C for 9 h. The characteristics of

Sang Yul Lee; Gwang Seok Kim; Bum-Suk Kim

2004-01-01

132

Evaluation of the TIG Welding Mechanical Behavior in AISI 316 Tubes for Fuel Rods.  

National Technical Information Service (NTIS)

The effect of service temperature, the mechanical resistance and the creep behaviour of a steel which is intended to be used as fuel rods in Nuclear Reactors was investigated. The tests were performed in seamless tubes of austenitic stainless steel, AISI ...

M. S. Q. Bittencourt S. Carvalho Perdigao

1985-01-01

133

Shielded Metal Arc Welding of AISI 4340 Alloy Steel. Welding Procedure Specification.  

National Technical Information Service (NTIS)

Procedure WPS-115 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for shielded metal arc welding of AISI 4340 alloy steel, in thickness range 0.187 to 2 inch; filler metal is E7018. (ERA citation 11:000915)

C. H. Wodtke D. R. Frizzell W. A. Plunkett

1985-01-01

134

Alberta Initiative for School Improvement: AISI Handbook for Cycle 3, 2006-2009  

ERIC Educational Resources Information Center

The purpose of the AISI (Alberta Initiative for School Improvement) Handbook for Cycle 3, 2006-2009 is to provide school authorities with the provincial and local requirements and processes for planning, funding, implementing, managing, evaluating, reporting and sharing school improvement projects. The handbook provides a framework for the…

Online Submission, 2006

2006-01-01

135

Nanocrystalline Surface Layer on AISI 52100 Steel Induced by Supersonic Fine Particles Bombarding  

NASA Astrophysics Data System (ADS)

Surface treatment of AISI 52100 steel by supersonic fine particles bombarding (SFPB) was studied in this article. The surface topography, morphology of the surface layer, and microhardness distribution of the surface layer have been investigated using a surface profiler system, a scanning electron microscopy (SEM), and a microvickers hardness tester. The microstructure, phase composition, and residual stress distribution of the surface layer in AISI 52100 steel after the SFBP treatment have been characterized by means of x-ray diffraction, SEM, and transmission electron microscopy. The results showed that a nanocrystalline surface (NS) layer was formed on the top surface of the SFBP-treated AISI 52100 steel samples. The NS layer is about 2 ?m in thickness with a surface roughness of R a = 1.2 ?m, R y = 6.7 ?m, R z = 6.0 ?m. Phase transitions occurred in the surface of the SFBP-treated samples. Residual compressive stress is obtained at the surface of the SFBP-treated samples. The maximum value of compressive stress appears at the outermost of the surface, and the affection region of the whole surface is about 60 ?m in thickness. A hardened surface layer has been fabricated in the AISI 52100 steel. The thickness of the hardened surface layer is about 70 ?m. The maximum value of hardness occurs at the depth of 20 ?m from the outermost surface.

Kong, Lingyan; Lao, Yuanxia; Xiong, Tianying; Li, Tiefan

2013-08-01

136

The effect of some heat treatment parameters on the dimensional stability of AISI D2  

Microsoft Academic Search

The tool steel AISI D2 is usually processed by vacuum hardening followed by multiple tempering cycles. It has been suggested that a deep cold treatment in between the hardening and tempering processes could reduce processing time and improve the final properties and dimensional stability. Hardened blocks were then subjected to various combinations of single and multiple tempering steps (520 and

Cord Henrik Surberg; Paul Stratton; Klaus Lingenhöle

2008-01-01

137

Modeling and Investigation of the Wear Resistance of Salt Bath Nitrided Aisi 4140 via ANN  

NASA Astrophysics Data System (ADS)

Nitriding is usually used to improve the surface properties of steel materials. In this way, the wear resistance of steels is improved. We conducted a series of studies in order to investigate the microstructural, mechanical and tribological properties of salt bath nitrided AISI 4140 steel. The present study has two parts. For the first phase, the tribological behavior of the AISI 4140 steel which was nitrided in sulfinuz salt bath (SBN) was compared to the behavior of the same steel which was untreated. After surface characterization using metallography, microhardness and sliding wear tests were performed on a block-on-cylinder machine in which carbonized AISI 52100 steel discs were used as the counter face. For the examined AISI 4140 steel samples with and without surface treatment, the evolution of both the friction coefficient and of the wear behavior were determined under various loads, at different sliding velocities and a total sliding distance of 1000 m. The test results showed that wear resistance increased with the nitriding process, friction coefficient decreased due to the sulfur in salt bath and friction coefficient depended systematically on surface hardness. For the second part of this study, four artificial neural network (ANN) models were designed to predict the weight loss and friction coefficient of the nitrided and unnitrided AISI 4140 steel. Load, velocity and sliding distance were used as input. Back-propagation algorithm was chosen for training the ANN. Statistical measurements of R2, MAE and RMSE were employed to evaluate the success of the systems. The results showed that all the systems produced successful results.

Ekinci, ?erafettin; Akdemir, Ahmet; Kahramanli, Humar

2013-08-01

138

Effect of microstructure on the thermal fatigue resistance of investment cast and wrought AISI H13 hot work die steel.  

National Technical Information Service (NTIS)

Variable thickness plate investment castings of AISI H13 hot work die steel were pour and characterized in the as-cast and heat treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and prem...

P. W. Hochanadel G. R. Edwards M. C. Maguire M. D. Baldwin

1995-01-01

139

Influence of the nitriding time in the wear behaviour of an AISI H13 steel during a crankshaft forging process  

Microsoft Academic Search

The influence of nitriding time in the wear behaviour of an AISI H13 hot work steel used on forging dies has been studied. AISI H13 steel was nitrided by a patented sursulf bath, varying nitriding time from 1 to 24h. Optical microscopy and microhardness deep profile through the nitrided layer were performed for each nitriding time. Standard pin-on-disk wear test

G. Castro; A. Fernández-Vicente; J. Cid

2007-01-01

140

Boriding response of AISI W1 steel and use of artificial neural network for prediction of borided layer properties  

Microsoft Academic Search

In the present study, boriding response of AISI W1 steel and prediction of boride layer properties were investigated by using artificial neural network (ANN). Boronizing heat treatment was carried out in a solid medium consisting of Ekabor-I powders at 850–1050 °C at 50 °C intervals for 1–8 h. The substrate used in this study was AISI W1. The presence of

Kenan Genel; Ibrahim Ozbek; Akif Kurt; Cuma Bindal

2002-01-01

141

Effect of rotational speed on the interface properties of friction-welded AISI 304L to 4340 steel  

Microsoft Academic Search

The aim of this study is to investigate experimentally the interface properties in terms of rotational speed in friction-welded AISI 304L to AISI 4340 alloy steel. Friction welding was conducted with five different rotational speeds using a direct-drive type friction welding machine. Friction pressure, forging pressure, friction time and forging time are fixed. The integrity of joints was investigated by

N. Özdemir; F. Sars?lmaz; A. Hasçal?k

2007-01-01

142

Assessment of XM-19 as a Substitute for AISI 348 in ATR Service  

SciTech Connect

It has been proposed that XM-19 alloy be considered as a possible replacement steel for AISI 348 in the construction of Advanced Test Reactor (ATR) capsules. AISI 348 works well, but is currently very difficult to obtain commercially. The superior and desirable mechanical properties of XM-19 alloy have been proven in non-nuclear applications, but no data are available regarding its use in radiation environments. While most 300 series alloys will meet the conditions required in ATR , it cannot be confidently assumed that XM-19 can be substituted without prior qualification in a radiation test. Compared to AISI 348, XM-19 will have an enhanced tendency for phase instabilities due to its higher levels of Ni and, especially, Si. However, transmutation of important elemental components in the highly thermalized ATR spectrum may have a very pronounced effect on its performance during irradiation. Not only will strong transmutation of Mn to Fe reduce the ductility and strength advantages provided by the higher initial Mn content of XM-19, but the extensive loss of Mn will also release from solution much of the N upon which the higher strength of XM-19 depends. In addition, the combined influence of transmutation and Inverse Kirkendall processes may lead to gas-bubble-covered grain boundaries, producing a very fragile alloy after significant irradiation has accumulated. At present, there are no radiation data available to substantiate this possible scenario. An alternate proposal is therefore advanced. Since the response of AISI 348 and 347 to radiation are expected to be relatively indistinguishable, the AISI 347 might serve as an acceptable replacement. While AISI 348 is usually chosen for nuclear service in order to reduce the overall radioactivity arising from relatively small amounts of highly transmutable elements such as cobalt, these elements have very little effect on the radiation performance of the steel. In the proposed application, however, the activity induced in this highly thermalized spectrum to large doses (10 to 50 dpa) will be overwhelmed by the activation arising from the major steel components: Fe, Cr, and especially Ni. The mechanical properties, irradiation creep, and void swelling behavior of the two steels should be practically indistinguishable.

F. A. Garner; L. R. Greenwood; R. E. Mizia; C. R. Tyler

2007-11-01

143

Behavior of AISI SAE 1020 Steel Implanted by Titanium and Exposed to Bacteria Sulphate Deoxidizer  

NASA Astrophysics Data System (ADS)

A hybrid technology to treat solid surfaces with the pulse high voltage and electric arc discharges of low pressure with a three-dimensional ion implantation technique (3DII) is applied. This technology is used to protect AISI SAE 1020 steel against a microbiological corrosion. The titanium ion implanted steel samples (coupons) are subjected to a medium of bacteria sulphate deoxidizer (BSD) which are very typical of the hydrocarbon industry and are potentially harmful for structures when are in contact with petroleum and some of its derivatives. The used technology aims to find an effective hybrid procedure to minimize the harmful effects of bacteria on AISI SAE 1020 steel. The hybrid technology efficiency of superficial titanium implantation is estimated through the measurements of the point corrosion characteristics obtained after testing both the treated and non-treated coupons. The three-dimensional surface structures of the samples are reconstructed with help of a confocal microscope.

Niño, Ely Dannier V.; Garnica, Hernán; Dugar-Zhabon, Veleriy; Castillo, Genis

2014-05-01

144

Determination of tribological properties of ion-nitrided AISI 5140 steel  

SciTech Connect

AISI 5140 low-alloy steel is ion-nitrided under different process parameters, including time (1, 4, and 8 h), temperature (450, 500, and 550 deg. C), and various gas mixtures at a working pressure of 5 mbar. The ion-nitriding behaviors of AISI 5140 steel have been assessed by evaluating tribological properties, surface hardness, surface roughness, compound layer thickness, and case depth by using a pin-on-disk wear machine, microhardness tester, surface profilometer, and scanning electron microscopy (SEM). It is found that ion nitriding improves the wear rate, and the presence of a hard and brittle compound layer on the surface causes an increase in wear of specimen surface. It is finally observed that ion nitriding parameters have no dominant effect on the friction coefficient.

Alsaran, Akguen

2002-09-15

145

Rolling-element fatigue life of AISI M-50 and 18-4-1 balls  

NASA Technical Reports Server (NTRS)

Rolling element fatigue studies were conducted with AISI M-50, EFR 18-4-1, and VAR 18-4-1. Groups of 12.7 mm (1/2-in) diameter balls of each material were tested in the five ball fatigue tester. Test conditions included a load of 1540 N (347 lbf) giving a maximum Hertz stress of 5520 MPa (800 000 psi), a shaft speed of 10,700 rpm, and a contact angle of 30 deg. Tests were run at a race temperature of 339 K (150 F) with a type 2 ester lubricant. The rolling element fatigue life of AISI M-50 was not significantly different from that of EFR 18-4-1 or VAR 18-4-1 based on a statistical comparison of the test results.

Parker, R. J.; Zaretsky, E. V.

1978-01-01

146

On electrical resistivity of AISI D2 steel during various stages of cryogenic treatment  

NASA Astrophysics Data System (ADS)

The effect of dislocation densities and residual stresses is well known in tool steels. Measurement of electrical resistivity in order to monitor dislocation densities or residual stresses has seldom been used in investigating the effect of cryogenic treatment on tool steels. Monitoring residual stresses during cryogenic treatment becomes important as it is directly related to changes due to cryogenic treatment of tool steels. For high carbon high chromium (HCHC- AISI D2) steels, not only wear resistance but dimensional stability is an important issue as the steels are extensively used in dies, precision measuring instruments. This work comprises of study of measurement of electrical resistivity of AISI D2 steel at various stages of cryogenic treatment. Use of these measurements in order to assess the dimensional stability of these steels is discussed in this paper.

Lomte, Sachin Vijay; Gogte, Chandrashekhar Laxman; Peshwe, Dilip

2012-06-01

147

Laser transformation hardening of AISI 440C martensitic stainless steel for higher cavitation erosion resistance  

Microsoft Academic Search

Surface hardening of AISI 440C martensitic stainless steel was achieved by laser transformation hardening (LTH) using a high-power CW Nd:YAG laser. A hardened layer of a few 100 ?m thick, composed of martensite, retained austenite and fine carbides was formed. The microstructure and hardness of the laser-treated layer were dependent on the laser processing parameters, with the hardness values reaching

K. H. Lo; F. T. Cheng; H. C. Man

2003-01-01

148

Laser surface hardening of AISI 420 stainless steel treated by pulsed Nd:YAG laser  

Microsoft Academic Search

The AISI 420 martensitic stainless steel was surface-hardened by a pulsed Nd:YAG laser. The influences of process parameters (laser pulse energy, duration time and travel speed) on the depth and hardness of laser treated area and its corrosion behavior were Investigated. In the optimum process parameters, maximum hardness (490VHN) in the laser surface treated area was achieved. The pitting corrosion

B. Mahmoudi; M. J. Torkamany; A. R. Sabour Rouh Aghdam; J. Sabbaghzade

2010-01-01

149

Evaluation of AISI 4140 Steel Repair Without Post-Weld Heat Treatment  

Microsoft Academic Search

The present work evaluates the two-layer technique on the heat affected zone (HAZ) of AISI 4140 steel welded with different\\u000a heat input levels between the first and second layer. The weld heat input levels selected by the Higuchi test were 5\\/5, 5\\/10,\\u000a and 15\\/5 kJ\\/cm. The evaluation of the refining and\\/or tempering of the coarsened grain HAZ of the first

Cleiton C. Silva; Victor H. C. de Albuquerque; Cícero R. O. Moura; Willys M. Aguiar; Jesualdo P. Farias

2009-01-01

150

Effects of carburization and hydrogenation on the impact toughness of AISI 4118 steel  

Microsoft Academic Search

The effects of hydrogen charging and carburization on the impact toughness of an AISI 4118 steel were studied. The carburization of impact specimens was conducted using a conventional pack carburizing method and the hydrogen charging was conducted in 1 N H2SO4 solution containing 1 g I?1 of thiourea at 30°C. Charpy V-notch impact tests were carried out on specimens with

Chih Fu Yang; Liu Ho Chiu; Jiann Kuo Wu

1995-01-01

151

Evaluation of toughness in AISI 4340 alloy steel austenitized at low and high temperatures  

Microsoft Academic Search

It has been reported for as-quenched AISI 4340 steel that high temperature austenitizing treatments at 1200°C, instead of conventional heat-treatment at 870°C, result in a two-fold increase in fracture toughness, K Ic, but a decrease in Charpy impact energy. This paper seeks to find an explanation for this discrepancy in Charpy and fracture toughness data in terms of the difference

Robert O. Ritchie; Benjamin Francis; William L. Server

1976-01-01

152

Dynamic JR curves and tension-impact properties of AISI 308 stainless steel weld  

Microsoft Academic Search

In this paper, instrumented tension-impact (dynamic tensile) and instrumented Charpy impact test results for AISI 308 stainless steel welds at room temperature are reported. A few Charpy specimens precracked to a\\/W (crack length to width ratio) ratios of 0.42 to 0.59 were also tested. Dynamic yield strength obtained from tension-impact test agrees well with that from Charpy V-notch specimens. The

P. R. Sreenivasan; S. L. Mannan

2000-01-01

153

Evaluation of AISI 4140 Steel Repair Without Post-Weld Heat Treatment  

Microsoft Academic Search

The present work evaluates the two-layer technique on the heat affected zone (HAZ) of AISI 4140 steel welded with different heat input levels between the first and second layer. The weld heat input levels selected by the Higuchi test were 5\\/5, 5\\/10, and 15\\/5 kJ\\/cm. The evaluation of the refining and\\/or tempering of the coarsened grain HAZ of the first

Cleiton C. Silva; Victor H. C. de Albuquerque; Cícero R. O. Moura; Willys M. Aguiar; Jesualdo P. Farias

2009-01-01

154

Study of the effect of heat treatment on hydrogen embrittlement of AISI 4340 steel  

Microsoft Academic Search

Delayed failure tests were performed on fully-quenched AISI 4340 steel tempered at 500 and 700° C, subjected to sustained tensile loads and cathodically charged with hydrogen (current density 10 mA cm-2) in an aqueous solution of 0.1 N sulphuric acid. The aim was to study the effect of the microstructure on the behaviour of steel towards the embrittling action of

E. Quadrini

1989-01-01

155

Enviromechanical testing of AISI 1020 steel in Hanford Grande Ronde groundwater  

Microsoft Academic Search

The relative susceptibility of AISI 1020 steel to environmentally assisted cracking (EAC) in Hanford Grande Ronde groundwater was investigated using slow-strain-rate (SSR) testing techniques. The groundwater flow rate and oxygen concentration levels were higher than those anticipated in the repository environment. No EAC was evident at a strain rate of 10⁻⁴\\/s. At a strain rate of 2 à 10⁻⁷\\/s, and

S. G. Pitman; R. E. Westerman; R. L. Fish

1983-01-01

156

Wear mechanisms and microstructure of pulsed plasma nitrided AISI H13 tool steel  

Microsoft Academic Search

AISI H13 tool steel discs were pulsed plasma nitrided during different times at a constant temperature of 400°C. Wear tests were performed in order to study the acting wear mechanisms. The samples were characterized by X-ray diffraction, scanning electron microscopy and hardness measurements. The results showed that longer nitriding times reduce the wear volumes. The friction coefficient was 0.20±0.05 for

M. V. Leite; C. A. Figueroa; S. Corujeira Gallo; A. C. Rovani; R. L. O. Basso; P. R. Mei; I. J. R. Baumvol; A. Sinatora

2010-01-01

157

Development of flow stress of AISI H13 die steel in hard machining  

Microsoft Academic Search

An approach was presented to characterize the stress response of workpiece in hard machining, accounting for the effect of\\u000a the initial workpiece hardness in addition to temperature, strain and strain rate on flow stress in this paper. AISI H13 die\\u000a steel was chosen to verify this methodology. The proposed flow stress model demonstrates a good agreement with experimental\\u000a data. Therefore,

Hong Yan; Guohua Qian; Qiang Hu

2007-01-01

158

Effects of conventional heat treatment on wear resistance of AISI H13 tool steel  

Microsoft Academic Search

Effects of conventional heat treatment on wear resistance of AISI H13 tool steel have been investigated. A pin-on-disc configuration at speed of 0.07m\\/s with two loads of 29.4 and 98N was employed to study the wear behavior. In order to understand wear mechanisms, wear tracks and debris were studied by scanning electron microscopy and X-ray methods. In addition, the depth

A. Bahrami; S. H. Mousavi Anijdan; M. A. Golozar; M. Shamanian; N. Varahram

2005-01-01

159

AISI\\/DOE Advanced Process Control Program Vol. 6 of 6: Temperature Measurement of Galvanneal Steel  

Microsoft Academic Search

This report describes the successful completion of the development of an accurate in-process measurement instrument for galvanneal steel surface temperatures. This achievement results from a joint research effort that is a part of the American Iron and Steel Institute's (AISI) Advanced Process Control Program, a collaboration between the U.S> Department of Energy and fifteen North American Steelmakers. This three-year project

S. W. Allison; D. L. Beshears; W. W. Manges

1999-01-01

160

Using Mather-type plasma focus device for surface modification of AISI304 Steel  

Microsoft Academic Search

A 2.8kJ plasma focus device with a nitrogen gas filling and a copper anode capsulated by aluminum was used to modify the surface of AISI304 steel substrate, in order to improve its properties. The treatment was carried out using a various number of nitrogen plasma focus shots at a pressure of 0.5mbar and at two steel sample distances (20 and

Sh. Al-Hawat; M. Soukieh; M. Abou Kharoub; W. Al-Sadat

2010-01-01

161

Theorical and experimental determination of the forming limit diagram for the AISI 304 stainless steel  

Microsoft Academic Search

The theoretical prediction and the experimental validation of the forming limit curve (FLC) have been made for the AISI 304 stainless steel during linear strain paths. The Marciniak–Kuczynski (M–K) method has been used in the theoretical prediction. For the calculation, the Hill’48 yield criterion has been used. For the experimental survey of the forming limit curve (FLC) we have used:

Haroldo Béria Campos; Marilena Carmen Butuc; José Joaquim Grácio; João E. Rocha; José Manuel Ferreira Duarte

2006-01-01

162

Nitrogen implantation of AISI 304 stainless steel with a coaxial plasma gun  

Microsoft Academic Search

The application of a plasma focus (PF) device operated at 1 kJ and 25 kV as a pulsed ion implanter is described. Samples of AISI 304 stainless steel implanted with nitrogen with this device show a reduction of wear of 42 times with respect to the implanted ones, with a reduction, at the same time of the friction coefficient. X-ray

J. N. Feugeas; E. C. Llonch; C. O. de Gonza´lez; G. Galambos

1988-01-01

163

Emission spectroscopy of plasma during laser welding of AISI 201 stainless steel  

Microsoft Academic Search

The rates of vaporization of alloying elements from the weld pool were related to the emission spectra of the plasma during\\u000a pulsed laser welding of AISI 201 stainless steel under various welding conditions. The temperature distribution in the plasma\\u000a was determined from the spectra obtained from various locations in the plasma plume. The extent of ionization of the plasma\\u000a was

M. M. Collur; T. Debroy

1989-01-01

164

Plasma nitriding of AISI 52100 ball bearing steel and effect of heat treatment on nitrided layer  

Microsoft Academic Search

.  In this paper an effort has been made to plasma nitride the ball bearing steel AISI 52100. The difficulty with this specific\\u000a steel is that its tempering temperature (~170–200°C) is much lower than the standard processing temperature (~460–580°C) needed\\u000a for the plasma nitriding treatment. To understand the mechanism, effect of heat treatment on the nitrided layer steel is investigated.\\u000a Experiments

RAVINDRA KUMAR; J ALPHONSA; RAM PRAKASH; K S BOOB; J GHANSHYAM; P A RAYJADA; P M RAOLE; S MUKHERJEE

165

Further considerations on the inconsistency in toughness evaluation of AISI 4340 steel austenitized at increasing temperatures  

Microsoft Academic Search

A study has been made of the influence of austenitizing temperature on the ambient temperature toughness of commercial AISI 4340 ultrahigh strength steel in the as-quenched (untempered) and quenched and tempered at 200°C conditions. As suggested in previous work, a systematic trend of increasing plane strain fracture toughness (K) Ic and decreasing Charpy V-notch energy is observed as the austenitizing

Robert O. Ritchie; R. M. Horn

1978-01-01

166

Antibacterial Property and Tribological Behavior of Duplex-Surface-Treated AISI 304 Stainless Steel  

Microsoft Academic Search

The duplex treatment of plasma alloying with Cu on plasma alloyed AISI 304 stainless steel with Ni is carried out using a double-glow plasma surface alloying technique. The antibacterial and unlubricated tribological properties of the un- treated, Ni-modified, and duplex-treated stainless steel have been investigated by using a spread plate method and a ball-on-disk wear testing method, respectively. The element

Xiangyu Zhang; Ailan Fan; Ruihua Zhu; Yong Ma; Bin Tang

2011-01-01

167

Characteristics of Laser Beam and Friction Stir Welded AISI 409M Ferritic Stainless Steel Joints  

Microsoft Academic Search

This article presents the comparative evaluation of microstructural features and mechanical properties of friction stir welded\\u000a (solid-state) and laser beam welded (high energy density fusion welding) AISI 409M grade ferritic stainless steel joints.\\u000a Optical microscopy, microhardness testing, transverse tensile, and impact tests were performed. The coarse ferrite grains\\u000a in the base material were changed to fine grains consisting duplex structure

A. K. Lakshminarayanan; V. Balasubramanian

2011-01-01

168

Corrosion resistance of ZrN films on AISI 304 stainless steel substrate  

Microsoft Academic Search

The corrosion resistance of ion-plated Zr, ZrN and ZrN\\/Zr films on commercial AISI 304 stainless steel has been investigated by electrochemical measurement. The electrolyte, 0.5 M H2SO4 containing 0.05 M KSCN, was used for the potentiodynamic polarization. The potentiodynamic scan was conducted from ?800 to 800 mV (SCE) with scan rate ranging from 10 to 600 mV\\/min. The N\\/Zr ratios

Wen-Jun Chou; Ge-Ping Yu; Jia-Hong Huang

2003-01-01

169

Tribological Properties of Borided AISI 4140 Steel with the Powder Pack-Boriding Method  

Microsoft Academic Search

The present study evaluates the tribological properties of boride layers on the surface of AISI 4140 steel, formed using the\\u000a pack-boriding method. Commercial EKabor®2 was used as the boronizing agent and the treatment was carried out at 900, 950, 1000, and 1050 °C for 2, 4, and 6 h, respectively.\\u000a X-ray diffraction (XRD), scanning electron microscopy (SEM), and microhardness tests were used

Mustafa Ulutan; M. Mustafa Yildirim; Osman N. Çelik; Soner Buytoz

2010-01-01

170

Effect of laser surface hardening on the hydrogen embrittlement of AISI 420: Martensitic stainless steel  

Microsoft Academic Search

The susceptibility of stress corrosion cracking (SCC) of AISI 420 which was surface transformed hardened by a pulsed Nd:YAG laser, was investigated in 5% sodium chloride+0.5% acetic acid solution by the U-Bend method, in the range of pH value from 3.5 to 6, in the absence and presence of 1ppm thiosulphate ion, at 25 and 60°C. The results showed that

B. Mahmoudi; M. J. Torkamany; A. R. Sabour Aghdam; J. Sabbaghzadeh

2011-01-01

171

Comparison of Dry and Wet End Milling of AISI 316 Stainless Steel  

Microsoft Academic Search

The aim of this study is to investigate the performance of dry and wet cutting during end milling of AISI 316 stainless steel. The milling experiments were carried out at two stages. First stage was conducted at a constant feed rate of 0.25 mm\\/rev, depth of cut of 0.3 mm and varying cutting speeds of 100, 150 and 200 m\\/min. Second stage was

B. Ozcelik; E. Kuram; B. T. Simsek

2011-01-01

172

Laser irradiation of AISI 316L stainless steel coated with Si 3N 4 and Ti  

Microsoft Academic Search

AISI 316L stainless steel was laser surface treated with different compositions of Si3N4 and Ti under various laser-processing parameters to improve its surface hardness through reinforcement of Ti-based silicides. The laser-treated regions exhibited improved surface hardness (250–1000HV), variations in the surface morphology (smooth and bowl like) and presence of cracks and pores depending upon the Si3N4–Ti composition and laser-processing parameters.

A. Viswanathan; D. Sastikumar; P. Rajarajan; Harish Kumar; A. K. Nath

2007-01-01

173

Evaluation on fatigue strength of AISI 4340 steel aluminum coated by electroplating and IVD processes  

Microsoft Academic Search

In spite of toxicity, hydrogen embrittlement susceptibility, and environmental issues, cadmium electroplating is usually applied\\u000a on high strength AISI 4340 aeronautical steel due to its efficient protection against electrochemical corrosion. Ion vapor\\u000a deposition (IVD) process with pure aluminum also offers good protection against corrosion with the advantages of decreasing\\u000a hydrogen embrittlement susceptibility and improving the fatigue strength of metallic components.

Herman Jacobus Cornelis Voorwald; Mauro Pedro Peres; Midori Yoshikawa Pitanga Costa; Maria Odila Hilário Cioffi

2010-01-01

174

Stress-Corrosion Cracking of AISI 4340 Steel in Aqueous Environments  

Microsoft Academic Search

Stress corrosion cracking of the high-strength martensitic steel AISI 4340 (yield stress = 1503 MPa) in NaCl aqueous solutions\\u000a of different concentrations was studied experimentally using compact tension specimens in free corroding conditions. The experiments\\u000a were conducted under the controls of constant load, constant crack opening displacement (COD), constant loading rate, and\\u000a constant COD rate. Despite the differences in controlling conditions, the experiments

Sergiy Kalnaus; Jixi Zhang; Yanyao Jiang

2011-01-01

175

Corrosion behaviour of AISI 316L stainless-steel alloys in diabetic serum.  

PubMed

The present study investigates the pitting-corrosion behaviour of AISI 316L stainless steel in human physiological fluids. The emphasis is on the effect of diabetic serum with glucose and proteins, but reference solutions of isotonic saline solution with and without antibiotics were also used. Polarization experiments were carried out, and the results point to the innocuity of those fluids on the performance of the alloy as far as pitting corrosion is concerned. PMID:10148337

Moura e Silva, T; Monteiro, J M; Ferreira, M G; Vieira, J M

1993-01-01

176

Stress corrosion cracking susceptibility of AISI 316 NG and 316 stainless steel in an impurity environment  

Microsoft Academic Search

The relative stress corrosion cracking (SCC) susceptibility of heat-treated AISI 316 nuclear grade (NG) and 316 stainless steel (SS) has been investigated by means of constant extension rate tensile (CERT) tests over a range of strain rates from 10⁻⁵ to 10⁻⁷ s⁻¹ in simulated boiling water reactor (BWR) environments that contain SOâ\\/sup 2 -\\/ as an impurity. It is observed

P. S. Maiya; W. J. Shack

1985-01-01

177

Sub-zero treatments of AISI D2 steel: Part I. Microstructure and hardness  

Microsoft Academic Search

Microstructure, hardness and wear behavior of AISI D2 steel subjected to varied sub-zero treatments have been examined with reference to conventional heat treatment. Part I of this work presents the variations of microstructure and hardness, whereas part II deals with the wear behavior. The sub-zero treatments studied are cold treatment, shallow cryogenic treatment and deep cryogenic treatment. The developed microstructures

Debdulal Das; Apurba Kishore Dutta; Kalyan Kumar Ray

2010-01-01

178

Tribological properties of oxidised boride coatings grown on AISI 4140 steel  

Microsoft Academic Search

In this study, we investigated the wear behaviour of borided and borided + short-duration oxidized AISI 4140 steel. Boronizing was carried out in a slurry salt bath consisting of borax, boric acid and ferro silicon. Also, short-duration oxidizing treatment was applied to borided steel to produce glass-like boron oxide layer. The short-duration oxidizing was performed at 750 °C for 3 min. Optical

Saduman Sen; Ugur Sen; Cuma Bindal

2006-01-01

179

Laser modification of detonation-gun sprayed ferro-boron coatings on AISI 304L SS  

Microsoft Academic Search

This study reports the synthesis of Ferro boron coatings deposited over AISI 304L austenitic stainless steel substrate using\\u000a D-Gun (Detonation gun) technique. The microstructure, adhesion and wear properties of the coating were investigated using\\u000a X-ray diffraction, optical microscopy, scanning electron microscopy, micro-hardness measurements and pin-on-disc wear tests.\\u000a Hardness of the coated surface was found to increase from 350 HV to

P. Shankar; N. R. Karthikeyan; M. Kamaraj; P. C. Angelo

2010-01-01

180

Sensitization resistance of friction stir welded AISI 409 M grade ferritic stainless steel joints  

Microsoft Academic Search

Friction stir welded low chromium AISI 409 M ferritic stainless steel was investigated for susceptibility to intergranular\\u000a corrosion by oxalic and double-loop electrochemical potentiodynamic reactivation tests, and the degree of sensitization were\\u000a evaluated by the ratio of the reactivating and activating currents. Stir zone of friction stir welded joint exhibited smaller\\u000a degree of sensitization compared to the base metal and it

A. K. Lakshminarayanan; V. Balasubramanian

181

Hot workability of spray-formed AISI M3:2 high-speed steel  

Microsoft Academic Search

Axisymmetric hot compression tests (900–1100°C) on spray-formed AISI M3:2 high-speed steel were performed in order to establish suitable parameters for hot forging of this material. Special attention was paid to establish the deformation conditions that lead to the breakdown of the carbide network, present after spray forming, and to avoid fracture of the material as a result of deformation. By

C. Rodenburg; M. Krzyzanowski; J. H. Beynon; W. M. Rainforth

2004-01-01

182

Microstructure, mechanical properties and chemical degradation of brazed AISI 316 stainless steel\\/alumina systems  

Microsoft Academic Search

The main aims of the present study are simultaneously to relate the brazing parameters with: (i) the correspondent interfacial microstructure, (ii) the resultant mechanical properties and (iii) the electrochemical degradation behaviour of AISI 316 stainless steel\\/alumina brazed joints. Filler metals on such as Ag–26.5Cu–3Ti and Ag–34.5Cu–1.5Ti were used to produce the joints. Three different brazing temperatures (850, 900 and 950°C),

O. C. Paiva; M. A. Barbosa

2008-01-01

183

Creep behavior of AISI 316 stainless steel above 0. 5 T[sub M  

SciTech Connect

AISI 316 austenitic stainless steel possesses a number of desirable properties, such as excellent high-temperature strength and corrosion resistance, for high temperature application. On the other hand, losses in tensile strength and fracture toughness after long-term use at high temperatures limit widespread applications of 316 stainless steel. In an effort to overcome these problems, researchers have made significant efforts to develop 316 stainless steel with improved high-temperature mechanical properties and efficiency. Recently, AISI 316 stainless steel has been focused on as the leading candidate of the structural materials in fusion reactors with their ever increasing demands on materials with high-temperature capability and good compatibility with coolant and irradiation properties. The main objective of the present paper is to report the static and cyclic creep behaviors of AISI 316 stainless steel at stresses between 206 and 285 MPa above 0.5 T[sub M] (melting temperature in Kelvin), i.e., steady state creep rate, stress exponent and activation energy for creep, and Larson-Miller parameters, as well as determine the creep deformation mechanisms.

Park, J.G.; Lee, D.Y. (Daelim Junior College, Anyang (Korea, Republic of). Dept. of Materials Engineering)

1993-09-01

184

Fatigue behavior of a 4140 steel coated with a NiMoAl deposit applied by HVOF thermal spray  

Microsoft Academic Search

The fatigue behavior of a quenched and tempered AISI 4140 steel has been investigated in three different conditions: as-polished, as-grit blasted with Al2O3 particles and as-coated, after grit blasting, with a deposit of Ni–Al–Mo alloy (Metco 447) of approximately 300 ?m in thickness, applied by HVOF thermal spraying. It has been determined that after grit blasting with particles of 20

K. Padilla; A. Velásquez; J. A. Berr??os; E. S. Puchi Cabrera

2002-01-01

185

Friction and wear mechanisms in AlMgB 14-TiB 2 nanocoatings  

Microsoft Academic Search

Recent tribological studies of AlMgB14-TiB2 nanocomposite coatings, sliding unidirectionally against AISI 52100 steel counterfaces under boundary-lubricated conditions, have shown sustained friction coefficient values as low as 0.02. While many industrial applications for wear-resistant coatings employ mineral oils as the lubricant, there is growing interest in the use of water-based, green alternatives. Additional performance evaluations of nanocomposite coatings in component-scale dynamometer

Clifton Higdon; Bruce A Cook; J. Harringa; A M Russell; J. Goldsmith; Jun Qu; Peter Julian Blau

2011-01-01

186

Sliding and abrasive wear of composite sol–gel alumina coated Al alloys  

Microsoft Academic Search

Alumina coatings, 60-?m thick (HV10g 647±144 kg mm?2), were deposited using a novel sol–gel technique on 6061 Al. The samples were subjected to dry sliding wear tests against hard bearing steel balls (SAE 52100 steel) and softer mild steel pins (AISI 1018 steel) at different sliding speeds and contact loads. Wear at low contact loads and sliding speeds was characterized

S Wilson; H. M Hawthorne; Q Yang; T Troczynski

2000-01-01

187

Remaining Strengths and Pitting Resistance of AISI 316 After a Fire Attack: Implications for Use as Concrete Rebars  

NASA Astrophysics Data System (ADS)

This study has looked into the tensile and the corrosion behavior of the AISI 316 austenitic stainless steel subjected to annealing temperature between 600 and 900 °C for up to 7 days. Discussion of results centers on using AISI 316 as concrete reinforcing bars. At a given temperature within this range, the tensile behavior is almost unaffected for annealing up to 7 days. However, there is a drastic change in fractography with annealing temperature. There is no relationship between the degree of sensitization and anodic polarization parameters. No relationship exists between annealing temperature and anodic polarization parameters, too. In comparison with ordinary carbon steel, the presence of Ca(OH)2 is much more beneficial to the pitting resistance of AISI 316.

Zeng, D.; Lo, K. H.; Cheang, K. H.; Lai, J. K. L.

2013-05-01

188

Evaluation of toughness in AISI 4340 alloy steel austenitized at low and high temperatures  

Microsoft Academic Search

It has been reported for as-quenched AISI 4340 steel that high temperature austenitizing treatments at 1200°C, instead of\\u000a conventional heat-treatment at 870°C, result in a two-foldincrease in fracture toughness,K\\u000a Ic, but adecrease in Charpy impact energy. This paper seeks to find an explanation for this discrepancy in Charpy and fracture toughness data\\u000a in terms of the difference betweenK\\u000a Ic and

Robert O. Ritchie; Benjamin Francis; William L. Server

1976-01-01

189

Influence of microstructure on micromagnetic Barkhausen emissions in AISI 4140 steel  

SciTech Connect

The effects of microstructure on the micromagnetic Barkhausen signal emissions in AISI 4140 steel are reported. The Barkhausen signal amplitude is known to be highly sensitive to the type and distribution of microstructural inhomogeneities, such as grain boundaries, precipitates and dislocations. The Barkhausen measurements were taken on samples having pearlitic, spheroidized and bainitic microstructures. The Barkhausen emissions were measured in terms of rms voltage, peak-to-peak voltage and number of events per cycle. It is shown that Barkhausen signals can be used to distinguish between pearlitic and bainitic microstructures.

Mitra, A.; Govindaraju, M.R.; Jiles, D.C. [Ames Lab., IA (United States)] [Ames Lab., IA (United States)

1995-11-01

190

Plasma characteristics of PTFE and hexafluoropropene deposition on AISI 1050 Stainless steel for lubrication  

NASA Astrophysics Data System (ADS)

Optical and electrical characteristics of sprayed polytetrafluoroethylene (PTFE) by Argon plasma and also hexafluoropropene (C3F6) plasma were measured for different plasma parameters (treatment time, type of gas, power, pressure, electrode distance). The coated thin film onto AISI 1050 stainless steel characteristics were also investigated. After the deposition, surface morphology was analysed by Scaning electron microscope (SEM), Energy-dispersive X-ray spectroscopy (EDS), Atomic force microscope (AFM). Abrasion of samples was tested. As a result of abrasion test the PTFE plasma processes more effective than C3F6 coating. This Work has been supported by TUBITAK TEYDEB project no:9100036

Teke, Erdogan; Bozduman, Ferhat; Gulec, Ali; Varol, Hatice; Manolache, Sorin; Camurlu, Erdem; Kurbanoglu, Cahit; Oksuz, Lutfi

2012-10-01

191

Microstructural Evolution During Friction Surfacing of Austenitic Stainless Steel AISI 304 on Low Carbon Steel  

NASA Astrophysics Data System (ADS)

Austenitic stainless steel AISI 304 coating was deposited over low carbon steel substrate by means of friction surfacing and the microstructural evolution was studied. The microstructural characterization of the coating was carried out by optical microscopy (OM), electron back scattered diffraction (EBSD), and transmission electron microscopy (TEM). The coating exhibited refined grains (average size of 5 ?m) as compared to the coarse grains (average size of 40 ?m) in as-received consumable rod. The results from the microstructural characterization studies show that discontinuous dynamic recrystallization (DDRX) is the responsible mechanism for grain evolution as a consequence of severe plastic deformation.

Khalid Rafi, H.; Kishore Babu, N.; Phanikumar, G.; Prasad Rao, K.

2013-01-01

192

Further considerations on the inconsistency in toughness evaluation of AISI 4340 steel austenitized at increasing temperatures  

Microsoft Academic Search

A study has been made of the influence of austenitizing temperature on the ambient temperature toughness of commercial AISI\\u000a 4340 ultrahigh strength steel in the as-quenched (untempered) and quenched and tempered at 200C conditions. As suggested\\u000a in previous work, a systematic trend ofincreasing plane strain fracture toughness(K)\\u000a \\u000a Ic\\u000a anddecreasing Charpy V-notch energy is observed as the austenitizing temperature is raised

Robert O. Ritchie; R. M. Horn

1978-01-01

193

Wet corrosion of a cw power laser melted AISI 304 stainless steel  

NASA Astrophysics Data System (ADS)

Thick plates of AISI 304 stainless steel were irradiated in air with a cw CO 2 laser beam without using anti-reflective coatings, under processing conditions giving rise to deep melting. A fully austenitic structure considerably refined in comparison with the original one was produced by the rapid solidification process. The laser-processed steel displayed improved values of the polarization resistance in an HCl acidic solution and the pitting resistance in an iron chloride solution. The laser-processed and original surfaces underwent generalized corrosion in a sulfide-chloride solution. The products were analyzed by means of Mössbauer spectroscopy, electron probe microanalysis and X-ray diffraction.

Carbucicchio, M.; Palombarini, G.; Savorelli, G.

1993-04-01

194

Effect of Cyclic Thermal Process on Ultrafine Grain Formation in AISI 304L Austenitic Stainless Steel  

Microsoft Academic Search

As-received hot-rolled commercial grade AISI 304L austenitic stainless steel plates were solution treated at 1060 °C to achieve\\u000a chemical homogeneity. Microstructural characterization of the solution-treated material revealed polygonal grains of about\\u000a 85-?m size along with annealing twins. The solution-treated plates were heavily cold rolled to about 90 pct of reduction in thickness.\\u000a Cold-rolled specimens were then subjected to thermal cycles at various

B. Ravi Kumar; B. Mahato; Sailaja Sharma; J. K. Sahu

2009-01-01

195

Study of Carbide Evolution During Thermo-Mechanical Processing of AISI D2 Tool Steel  

NASA Astrophysics Data System (ADS)

The microstructure of a cold-worked tool steel (AISI D2) with various thermo-mechanical treatments was examined in the current study to identify the effects of these treatments on phases. X-ray diffraction was used to identify phases. Microstructural changes such as spheroidization and coarsening of carbides were studied. Thermodynamic calculations were used to verify the results of the differential thermal analysis. It was found that soaking temperature and time have a large influence on dissolution, precipitation, spheroidization, and coalescence of carbides present in the steel. This consequently influences the hot workability and final properties.

Bombac, D.; Fazarinc, M.; Podder, A. Saha; Kugler, G.

2013-03-01

196

Pre- and postirradiation properties of brazed joints of AISI 316L stainless steel  

NASA Astrophysics Data System (ADS)

An extensive test campaign has been performed to verify the reliability and the endurance of brazed joints between AISI 316L parts for structural applications in the nuclear field. The tests, conducted for comparison with three different high melting temperature alloys, included tensile tests (normal and shear), fatigue tests (fatigue crack propagation, low cycle fatigue, 4-point bending fatigue) and impact tests; besides, tensile tests have been performed with both unirradiated and irradiated specimens. Generally, the tests demonstrated satisfactory mechanical properties of the joints and revealed occasionally strong differences in the behaviour of the different brazing alloys, thus providing important design indications.

Brossa, M.; Franconi, E.; Guerreschi, U.; Pierazzi, L.; Poggi, P.; Rustia, V.

1994-09-01

197

Experimental and analytical load-life relation for AISI 9310 steel spur gears  

NASA Technical Reports Server (NTRS)

Life tests were conducted at three different loads with three groups of 8.9 cm, pitch diameter spur gears made of vacuum arc remelted AISI 9310 steel. Life was found to vary inversely with load to the 4.3 and 5.1 power at the L-10 and L-50 life levels, respectively. The Weibull slope varied linearly with maximum Hertz contact stress, having an average value of 2.5. The test data when compared to AGMA standards showed a steeper slope for the load-life diagram.

Townsend, D. P.; Coy, J. J.; Zaretsky, E. V.

1977-01-01

198

Experimental and Analytical Load-Life Relation for AISI 9310 Steel Spur Gears  

NASA Technical Reports Server (NTRS)

Life tests were conducted at three different loads with three groups of 8.9 cm pitch diameter spur gears made of vacuum arc remelted VAR AISI 9310 steel. Life was found to vary inversely with load to the 4.3 and 5.1 power at the L10 sub and L50 sub life levels, respectively. The Weibull slope varied linearly with maximum Hertz contact stress, having an average value of 2.5. The test data when compared to AGMA standards showed a steeper slope for the load-life diagram.

Townsend, D. P.; Coy, J. J.; Zaretsky, E. V.

1977-01-01

199

Study of passive films formed on AISI 304 stainless steel by impedance measurements and photoelectrochemistry  

SciTech Connect

Moss-Schottky plots and photoelectrochemical measurements were made on films formed at different potentials on AISI 304 stainless steel in a borate/boric acid solution, pH 9.2. The results allowed the determination of the semiconductive properties and band structure of the films, which account for the existence of two kinds of films depending on the formation potential. For potentials below 0 V (SCE), the results point out for a film with an inverse spinel structure constituted by Cr-substituted magnetite with two donor levels. Above 0 V only one donor level is detected, which should be Fe{sup 2 +} on tetrahedral sites.

Simoes, A.M.P.; Ferreiro, M.G.S. (Dept. de Engenharia Quimica, Instituto Superior Tecnico, 1096 Lisboa Codex (PT)); Rondot, B.; Belo, M. (Centre National de la Recherche Scientifique, 94 - Vitry-sur-Seine (France). Centre d'Etudes de Chimie Metallurgique)

1990-01-01

200

A comparative study on tribological behavior of TiN and TiAlN coatings prepared by arc ion plating technique  

Microsoft Academic Search

TiN and TiAlN coatings were deposited onto AISI D2 steel substrates by an arc ion plating (AIP) technique. These coatings were comparatively studied on their tribological behaviors. For this study, the dry sliding wear experiments were conducted on TiN and TiAlN-coated steel discs at two different contact loads, 1 N and 5 N, and three different sliding speeds, 0.1, 0.3,

Seog-Young Yoon; Jong-Kuk Kim; Kwang Ho Kim

2002-01-01

201

Comportamento anodico do aco inoxidavel ferritico AISI 430 em solucoes aquosas contendo ions cloreto ou ions sulfato. (Anodic behaviour of the stainless steel AISI 430 in aqueous solutions of chloride and sulphate ions).  

National Technical Information Service (NTIS)

The kinetics of the dissolution of stainless steel AISI 430 in the presence of chloride and sulphate ions has been studied in terms of the ion concentration, the pH variation, and the velocity of the working electrode. The experimental method utilized was...

M. Z. Sebrao

1982-01-01

202

Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes  

SciTech Connect

In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

Umbrello, Domenico; Rizzuti, Stefania [Department of Mechanical Engineering, University of Calabria 87036 Rende (Italy); Outeiro, Jose C. [Portuguese Catholic University, 3080-024 Figueira da Foz (Portugal); Shivpuri, Rajiv [Industrial, Welding and Systems Engineering - Ohio State University 43210 Columbus (United States)

2007-04-07

203

Modeling of the flow stress for AISI H13 Tool Steel during Hard Machining Processes  

NASA Astrophysics Data System (ADS)

In general, the flow stress models used in computer simulation of machining processes are a function of effective strain, effective strain rate and temperature developed during the cutting process. However, these models do not adequately describe the material behavior in hard machining, where a range of material hardness between 45 and 60 HRC are used. Thus, depending on the specific material hardness different material models must be used in modeling the cutting process. This paper describes the development of a hardness-based flow stress and fracture models for the AISI H13 tool steel, which can be applied for range of material hardness mentioned above. These models were implemented in a non-isothermal viscoplastic numerical model to simulate the machining process for AISI H13 with various hardness values and applying different cutting regime parameters. Predicted results are validated by comparing them with experimental results found in the literature. They are found to predict reasonably well the cutting forces as well as the change in chip morphology from continuous to segmented chip as the material hardness change.

Umbrello, Domenico; Rizzuti, Stefania; Outeiro, José C.; Shivpuri, Rajiv

2007-04-01

204

Modelling of Tool Wear and Residual Stress during Machining of AISI H13 Tool Steel  

NASA Astrophysics Data System (ADS)

Residual stresses can enhance or impair the ability of a component to withstand loading conditions in service (fatigue, creep, stress corrosion cracking, etc.), depending on their nature: compressive or tensile, respectively. This poses enormous problems in structural assembly as this affects the structural integrity of the whole part. In addition, tool wear issues are of critical importance in manufacturing since these affect component quality, tool life and machining cost. Therefore, prediction and control of both tool wear and the residual stresses in machining are absolutely necessary. In this work, a two-dimensional Finite Element model using an implicit Lagrangian formulation with an automatic remeshing was applied to simulate the orthogonal cutting process of AISI H13 tool steel. To validate such model the predicted and experimentally measured chip geometry, cutting forces, temperatures, tool wear and residual stresses on the machined affected layers were compared. The proposed FE model allowed us to investigate the influence of tool geometry, cutting regime parameters and tool wear on residual stress distribution in the machined surface and subsurface of AISI H13 tool steel. The obtained results permit to conclude that in order to reduce the magnitude of surface residual stresses, the cutting speed should be increased, the uncut chip thickness (or feed) should be reduced and machining with honed tools having large cutting edge radii produce better results than chamfered tools. Moreover, increasing tool wear increases the magnitude of surface residual stresses.

Outeiro, José C.; Umbrello, Domenico; Pina, José C.; Rizzuti, Stefania

2007-05-01

205

Effect of mechanical activation on jell boronizing treatment of the AISI 4140  

NASA Astrophysics Data System (ADS)

The article presents the effect of mechanical activation on the growth kinetics of boride layer of boronized AISI 4140 steel. The samples were boronized by ferroboron + (SiO2-Na2O) powders for 873-1173 K temperature and 2, 4, 6 and 8 h times, respectively. The morphology and types of borides formed on the surface of AISI 4140 steel substrate were analyzed. Layer growth kinetics were analyzed by measuring the extent of penetration of FeB and Fe2B sublayers as function of treatment time and temperature in the range of 873-1173 K. High diffusivity was obtained by creating a large number of defects through mechanical activation in the form of nanometer sized crystalline particles through the repeated fracturing and cold-welding of the powder particles, and a depth of 100 ?m was found in the specimen borided by the 2 h MA powders, for 4 h and 1073 K, where 2000-2350 HV were measured. Consequently, the application conditions of boronizing were improved by usage of mechanical activation. The preferred Fe2B boride without FeB could be formed in the boride layer under 973 K boronizing temperature by mechanically activated by ferroboron + sodium silicate powder mixture due to the decrease of the activation energy.

Y?lmaz, S. O.; Karata?, S.

2013-06-01

206

Determination of Proper Austenitization Temperatures for Hot Stamping of AISI 4140 Steel  

NASA Astrophysics Data System (ADS)

High strength steels are desirable materials for use in automobile bodies in order to reduce vehicle weight and increase the safety of car passengers, but steel grades with high strength commonly show poor formability. Recently, steels with controlled microstructures and compositions are used to gain adequate strength after hot stamping while maintaining good formability during processing. In this study, microstructure evolutions and changes in mechanical properties of AISI 4140 steel sheets resulting from the hot stamping process at different austenitization temperatures were investigated. To determine the proper austenitization temperatures, the results were compared with those of the cold-worked and cold-worked plus quench-tempered specimens. Comparisons showed that the austenitization temperatures of 1000 and 1100 °C are proper for hot stamping of 3-mm-thick AISI 4140 steel sheets due to the resultant martensitic microstructure which led to the yield and ultimate tensile strength of 1.3 and 2.1 GPa, respectively. Such conditions resulted in more favorable simultaneous strength and elongation than those of hot-stamped conventional boron steels.

Samadian, Pedram; Parsa, Mohammad Habibi; Shakeri, Amid

2014-04-01

207

Improvement in cavitation erosion resistance of AISI 316L stainless steel by friction stir processing  

NASA Astrophysics Data System (ADS)

Commercial AISI 316L plates with the initial grain size of 14.8 ?m were friction stir processed (FSP) with different processing parameters, resulting in two fine-grained microstructures with the grain sizes of 4.6 and 1.7 ?m. The cavitation erosion behavior, before and after FSP, was evaluated in terms of incubation time, cumulative mass loss and mean depth of erosion. A separate cavitation erosion test was performed on the transverse cross section of a FSP sample to reveal the effect of grain structure. It was observed that FSP samples, depending on their grain size, are at least 3-6 times more resistant than the base material against cavitation erosion. The improvement in cavitation erosion resistance is attributed to smaller grain structure, lower fraction of twin boundaries, and favorable crystallographic orientation of grains in FSP samples. The finer the grain size, the more cavitation erosion resistance was achieved. Moreover, the microstructures of eroded surfaces were studied using a scanning electron microscope equipped with EBSD, and an atomic force microscope. The mechanisms controlling the cavitation erosion damage in friction stir processed AISI 316L are also discussed.

Hajian, M.; Abdollah-zadeh, A.; Rezaei-Nejad, S. S.; Assadi, H.; Hadavi, S. M. M.; Chung, K.; Shokouhimehr, M.

2014-07-01

208

Surface Treatments for Improved Performance of Spinel-coated AISI 441 Ferritic Stainless Steel  

SciTech Connect

Ferritic stainless steels are promising candidates for IT-SOFC interconnect applications due to their low cost and resistance to oxidation at SOFC operating temperatures. However, steel candidates face several challenges; including long term oxidation under interconnect exposure conditions, which can lead to increased electrical resistance, surface instability, and poisoning of cathodes due to volatilization of Cr. To potentially extend interconnect lifetime and improve performance, a variety of surface treatments were performed on AISI 441 ferritic stainless steel coupons prior to application of a protective spinel coating. The coated coupons were then subjected to oxidation testing at 800 and 850°C in air, and electrical testing at 800°C in air. While all of the surface-treatments resulted in improved surface stability (i.e., increased spallation resistance) compared to untreated AISI 441, the greatest degree of improvement (through 20,000 hours of testing at 800°C and 14,000 hours of testing at 850°C) was achieved by surface blasting.

Stevenson, Jeffry W.; Riel, Eric M.; Stephens, Elizabeth V.; Khaleel, Mohammad A.

2013-01-01

209

Hall Petch Behavior in Ultra-Fine-Grained AISI 301LN Stainless Steel  

NASA Astrophysics Data System (ADS)

An ultra-fine-grained AISI 301LN austenitic stainless steel has been achieved by heavy cold rolling, to induce the formation of martensite, and subsequent annealing at 800 °C, 900 °C, and 1000 °C, from 1 to 100 seconds. The microstructural evolution was analyzed using transmission electron microscopy and the yield strength determined by tension testing. Ultra-fine austenite grains, as small as ˜0.54 ?m, were obtained in samples annealed at 800 °C for 1 second. For these samples, tensile tests revealed a very high yield strength of ˜700 MPa, which is twice the typical yield strength of conventional fully annealed AISI 301LN stainless steels. An analysis of the relationship between yield strength and grain size in these submicron-grained stainless steels indicates a classical Hall Petch behavior. Furthermore, when the yield dependence on annealing temperature is considered, the results show that the Hall Petch relation is due to an interplay between fine-grained austenite, solid solution strengthening, precipitate hardening, and strain hardening.

Rajasekhara, S.; Ferreira, P. J.; Karjalainen, L. P.; Kyröläinen, A.

2007-06-01

210

Pitting and Intergranular Corrosion Resistance of AISI Type 301LN Stainless Steels  

NASA Astrophysics Data System (ADS)

The pitting and intergranular corrosion (IGC) resistance of AISI type 301LN stainless steels were evaluated using ASTM methods, anodic polarization, and electrochemical impedance techniques. The IGC results indicated that the microstructure of the samples after sensitization heat treatment at 675 °C for 1 h shows step or dual structure for both imported and indigenous materials indicating insignificant Cr23C6 precipitation. The results of immersion tests in boiling 6% copper sulfate + 16% sulfuric acid + copper solution for 24 h followed by the bend test (ASTM A262 Practice-E method) indicated no crack formation in any of the tested specimens. Pitting corrosion resistance carried out in 6% FeCl3 solution at different temperatures of 22 ± 2 and 50 ± 2 °C (ASTM G 48) up to the period of 72 h revealed pitting corrosion attack in all the investigated alloys. The potentiodynamic anodic polarization results in 0.5 M NaCl revealed variation in passive current density and pitting potential depending on the alloy chemistry and metallurgical condition. The passive film properties studied by electrochemical impedance spectroscopy (EIS) correlated well with the polarization results. The x-ray diffraction (XRD) results revealed the presence of austenite (?) and martensite (?') phases depending on the material condition. The suitability of three indigenously developed AISI type 301LN stainless steels were compared with imported type 301LN stainless steel and the results are highlighted in this article.

Ningshen, S.; Kamachi Mudali, U.

2010-03-01

211

A Computational Study of Plastic Deformation in AISI 304 Induced by Surface Mechanical Attrition Treatment  

NASA Astrophysics Data System (ADS)

As a technique of grain refinement process by plastic deformation, surface mechanical attrition treatment (SMAT) has been developed to be one of the most effective ways to optimize the mechanical properties of various materials including pure metals and alloys. SMAT can significantly reduce grain size into nanometer regime in the surface layer of bulk materials, providing tremendous opportunities for improving physical, chemical and mechanical properties of the materials. In this work, a computational modeling of the surface mechanical attrition treatment (SMAT) process is presented, in which Johnson-Cook plasticity model and the finite element method were employed to study the high strain rate, elastic-plastic dynamic process of ball impact on a metallic target. AISI 304 steel with low stacking fault energy was chosen as the target material. First, a random impact model was used to analyze the statistic characteristics of ball impact, and then the plastic deformation behavior and residual stress distribution in AISI 304 stainless steel during SMAT were studied. The simulation results show that the compressive residual stress and vertical deformation of the surface structures were directly affected by ball impact frequency, incident impact angle and ball diameter used in SMAT process.

Zhang, X. C.; Lu, J.; Shi, S. Q.

2010-05-01

212

Variation in sessile microflora during biofilm formation on AISI-304 stainless steel coupons.  

PubMed

Coupons of stainless steel type AISI-304 were exposed to the industrial cooling system of a petrochemical plant fed by seawater from the Guanabara Bay, Rio de Janeiro, Brazil, in order to study the in situ formation of biofilms. Bacteria, microalgae and fungi were detected on the coupons as soon as 48 h after exposure. Their respective numbers were determined at times 48, 96 and 192 h and over the following 8 weeks. Aerobic, anaerobic and sulfate-reducing bacteria were quantified according to the technique of the most probable number, and fungi by the pour plate technique. The number of microorganisms present in the forming biofilm varied over the experimental period, reaching maximal levels of 14 x 10(11) cells cm-2, 30 x 10(13) cells cm-2, 38 x 10(11) cells cm-2 and 63 x 10(5) cells cm-2, respectively, for aerobic bacteria, anaerobic bacteria, sulfate-reducing bacteria and fungi, and the dynamics of this variation depended on the group of microorganisms. Bacillus sp, Escherichia coli, Serratia sp and Pseudomonas putrefaciens were identified among the aerobic bacteria isolated. Additionally, microalgae and bacteria of the genus Gallionella were also detected. Nonetheless, no evidence of corrosion was found on the stainless steel type AISI-304 coupons over the experimental period. PMID:8987686

de França, F P; Lutterbach, M T

1996-07-01

213

The Effects of Process Variables on the Case Depth of Laser Transformation Hardened AISI 01 Tool Steel Specimens  

Microsoft Academic Search

An investigation was carried out to study the effects of speed, nozzle gap and power input on the case depth of laser transformation hardened ASSAB DF2 (equivalent to AISI 01) tool steel specimens. The specimens, used were 5 and 10 mm thick and 10 and 25 mm in diameter. A defocussed beam from a fast axial flow C02 laser was

L. J. Yang; S. Jana; S. C. Tarn; L. E. N. Lim

1994-01-01

214

HARD TURNING PLUS GRINDING–A COMBINATION TO OBTAIN GOOD SURFACE INTEGRITY IN AISI O1 TOOL STEEL MACHINED PARTS  

Microsoft Academic Search

The establishment of adequate machining guidelines requires the study of several factors (residual stresses, roughness, hardness, microstructural changes, etc.) that define the surface integrity generated in the part by a machining operation. This work studies the surface integrity generated in AISI O1 tool steel by four hard turning (conventional, laser assisted, MQL and conventional with worn tool) and two grinding

V. García Navas; C. García-Rosales; J. Gil Sevillano; I. Ferreres; J. A. Marañón

2008-01-01

215

Influence of the starting condition on the kinetics of sensitization and loss of toughness in an AISI 304 steel  

Microsoft Academic Search

This work describes the investigation of the embrittlement of AISI 304 steel sensitized at 650°C by Charpy impact test, comparing two starting conditions: (1) mill annealed and machined (MA-M); and (2) solution treated at 1050°C by 1 h followed by oil quenching (ST). The degree of sensitization for both samples was assessed by Optical Microscopy (OM), Scanning Electron Microscopy (SEM)

S. S. M. Tavares; M. P. Cindra Fonseca; Alex Maia; Pedro de Lima-Neto

2003-01-01

216

CRECIMIENTO DE PELICULAS PLASMO POLIMERIZADAS EN SUBSTRATOS DE ACERO AISI 4140: ESTUDIO EXPERIMENTAL DE LA RESPUESTA A PROCESOS DE CORROSIÓN  

Microsoft Academic Search

In this work the application of Plasma Polymerization technique for the deposition of thin Diamond-Like Carbon (DLC) films on steel AISI 4140 surface appears. A reactive Methane (CH4) atmosphere was used as a monomer to generate a polymeric film over steel substrate surface. Anticorrosive properties of deposited films were determined by means of the potential dynamic curves analysis in Taffel

N. Y. Niño; E. Vera; M. Valera; L. F. Vesga; M. H. Guerra-Mutis

217

Application of response surface methodology in describing the performance of coated carbide tools when turning AISI 1045 steel  

Microsoft Academic Search

The performance of a multilayer tungsten carbide tool was described using response surface methodology (RSM) when turning AISI 1045 steel. Cutting tests were performed with constant depth of cut and under dry cutting conditions. The factors investigated were cutting speed, feed and the side cutting edge angle (SCEA) of the cutting edge. The main cutting force, i.e. the tangential force

M. Y. Noordin; V. C. Venkatesh; S. Sharif; S. Elting; A. Abdullah

2004-01-01

218

Modelling of surface finish and tool flank wear in turning of AISI D2 steel with ceramic wiper inserts  

Microsoft Academic Search

Tool nose design affects the surface finish and productivity in finish hard turning processes. Surface finishing and tool flank wear have been investigated in finish turning of AISI D2 steels (60 HRC) using ceramic wiper (multi-radii) design inserts. Multiple linear regression models and neural network models are developed for predicting surface roughness and tool flank wear. In neural network modelling,

Tugrul Özel; Yigit Karpat; Luís Figueira; J. Paulo Davim

2007-01-01

219

Effects of Ultrasonic Nanocrystal Surface Modification (UNSM) on Residual Stress State and Fatigue Strength of AISI 304  

NASA Astrophysics Data System (ADS)

The effects of a new mechanical surface treatment method, called ultrasonic nanocrystal surface modification (UNSM), on near-surface microstructures and residual stress states as well as on the fatigue behavior of an austenitic steel AISI 304 are investigated and discussed. The results are compared with consequences of other mechanical surface treatment methods such as deep rolling or shot peening.

Cherif, A.; Pyoun, Y.; Scholtes, B.

2010-03-01

220

Microstructure of a Small Scale AISI 316 Stainless Steel Pumped Sodium Loop Following Operation for 20,000H.  

National Technical Information Service (NTIS)

A small pumped loop constructed of AISI 316 stainless steel has been operated for 20,000 hrs. with a peak temperature of 635 exp 0 C. Marked decarburisation was observed in the preheater and in the adjacent specimen chamber. No regions of significant carb...

W. Charnock J. Gwyther P. Marshall

1980-01-01

221

A study on friction and wear behaviour of carburized, carbonitrided and borided AISI 1020 and 5115 steels  

Microsoft Academic Search

The friction and wear characteristics of AISI 1020 and 5115 steel surfaces improved by various thermochemical heat treatments such as carburizing, carbonitriding and boronizing were determined. Samples prepared from the test materials were treated at liquid and gases carburizing, gases carbonitriding and solid boronizing mediums. The hardness distributions, microstructures and X-ray diffraction studies were performed.The wear tests were carried out

B Selçuk; R Ipek; M. B Karam??

2003-01-01

222

Influence of the martensitic transformation on the deformation behaviour of an AISI 316 stainless steel at low temperatures  

Microsoft Academic Search

The deformation behaviour of an AISI 316 stainless steel under uniaxial tension was examined at 25, - 70 and - 196° C. The flow curves exhibited peculiar shapes and the work hardening rates were found to increase with strain beyond certain values of plastic strain. X-ray diffraction analyses showed that the transformation toa-martensite commenced at these values of plastic strain

V. Seetharaman; R. Krishnan

1981-01-01

223

Correlation between processing parameters and strain-induced martensitic transformation in cold worked AISI 301 stainless steel  

Microsoft Academic Search

In this paper, the effect of cold-work temperature, the amount of deformation, the strain rate and the initial austenite grain size on the volume fraction of strain-induced martensite in AISI 301 stainless steel alloy was modeled by means of Artificial Neural Networks (ANNs). The optimal ANN architecture and training algorithm were determined. The results of the ANN model were in

H. Mirzadeh; A. Najafizadeh

2008-01-01

224

Surface fatigue life and failure characteristics of EX-53, CBS 1000M, and AISI 9310 gear materials  

NASA Technical Reports Server (NTRS)

Spur gear endurance tests and rolling-element surface fatigue tests are conducted to investigate EX-53 and CBS 1000M steels for use as advanced application gear materials, to determine their endurance characteristics, and to compare the results with the standard AISI 9310 gear material. The gear pitch diameter is 8.89 cm (3.50 in). Gear test conditions are an oil inlet temperature of 320 K (116 F), an oil outlet temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench-type rolling-element fatigue tests are conducted at ambient temperature with a bar specimen speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPa (700 ksi). The EX-53 test gears have a surface fatigue life of twice that of the AISI 9310 spur gears. The CBS 1000M test gears have a surface fatigue life of more than twice that of the AISI 9310 spur gears. However, the CBS 1000M gears experience a 30-percent tooth fracture failure which limits its use as a gear material. The rolling-contact fatigue lines of RC bar specimens of EX-53 and ASISI 9310 are approximately equal. However, the CBS 1000M RC specimens have a surface fatigue life of about 50 percent that of the AISI 9310.

Townsend, D. P.

1985-01-01

225

An Experimental Investigation into the Effect of Minimum Quality Lubricant on Cutting Temperature for Machinability of AISI 9310 Steel Alloy  

Microsoft Academic Search

Industries and researchers are trying to reduce the use of coolant lubricant fluids in metal cutting to obtain safety, environmental and economical benefits. This work is focused on the effect of minimal quantity lubricant on chip-tool interface temperature under different cutting velocity and feed rate in turning of AISI 9310 steel. Chip-tool interface temperatures were measured for three different cooling

M. M. Rahman; M. M. A. Khan; N. R Dhar

226

Studies on the determination of surface deuterium in AISI 1062, 4037, and 4140 steels by secondary ion mass spectrometry  

NASA Astrophysics Data System (ADS)

The concentration of deuterium at the surface of cathodically charged high strength steels AISI 1062, 4037, and 4140 has been determined by secondary ion mass spectrometry (SIMS). The beneficial effects of pickling in NAP (a mixture of nitric, acetic, and phosphoric acids) to remove surfacebound deuterium have been observed.

Sastri, V. S.; Donepudi, V. S.; McIntyre, N. S.; Johnston, D.; Revie, R. W.

1988-12-01

227

Microstructure and corrosion behavior of the AISI 304 stainless steel after Nd:YAG pulsed laser surface melting  

Microsoft Academic Search

Different laser energy densities were utilized to treat AISI 304 stainless steel via Nd:YAG pulsed laser surface melting (LSM). The surface composition and microstructure of the stainless steel were characterized using X-ray diffraction (XRD), scanning electron microscopy (SEM) and field emission scanning electron microscopy (FESEM). In particular, the corrosion behaviors of the stainless steel surface without and with LSM were

C. Y. Cui; X. G. Cui; Y. K. Zhang; Q. Zhao; J. Z. Lu; J. D. Hu; Y. M. Wang

2011-01-01

228

Rutherford backscattering spectrometry (RBS) characterization of oxide scale formed on (AISI304) steel after surface deposition of lanthanum  

Microsoft Academic Search

Oxidized AISI-304 steel samples coated with lanthanum have been investigated by Rutherford backscattering spectrometry (RBS) in order to determine the composition profile of the oxide scale. In this sense, RBS technique has been revealed as a very reliable and nondestructive method for depth profile analysis. Lanthanum deposition, specially over preoxidized specimens, has proven to improve their resistance to high temperature

F. J. Ager; M. A. Respaldiza; J. J. Benitez; J. C. Soares; M. F. da Silva; J. A. Odriozola

1996-01-01

229

Welding Procedure Specification. Supplement 1. Records of Procedure Qualification Tests. Shielded Metal Arc Welding of AISI 4340 Alloy Steel.  

National Technical Information Service (NTIS)

Procedure WPS-115 is qualified under Section IX of the ASME Boiler and Pressure Vessel Code for shielded metal arc welding of AISI 4340 alloy steel, in thickness range 0.187 to 2.0 inch; filler metal is E7018. (ERA citation 11:040938)

C. H. Wodtke D. R. Frizzell W. A. Plunkett

1986-01-01

230

Friction and wear of Synfluo 180XF wax and nano-Al 2O 3 filled Nomex fabric composites  

Microsoft Academic Search

Nomex fabric composites filled with the particulates of Synfluo 180XF wax (SFW) and nano-Al2O3 was prepared by dip-coating of Nomex fabric in a phenolic resin containing particulates to be incorporated and the successive curing. The friction and wear performance of the pure and filled Nomex fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration were evaluated on a Xuanwu-III

Feng-Hua Su; Zhao-Zhu Zhang; Kun Wang; Wei-min Liu

2006-01-01

231

Tensile and fatigue data for irradiated and unirradiated AISI 310 stainless steel and titanium - 5 percent aluminum - 2.5 percent tin: Application of the method of universal slopes  

NASA Technical Reports Server (NTRS)

Irradiated and unirradiated tensile and fatigue specimens of AISI 310 stainless steel and Ti-5Al-2.5Sn were tested in the range of 100 to 10,000 cycles to failure to determine the applicability of the method of universal slopes to irradiated materials. Tensile data for both materials showed a decrease in ductility and increase in ultimate tensile strength due to irradiation. Irradiation caused a maximum change in fatigue life of only 15 to 20 percent for both materials. The method of universal slopes predicted all the fatigue data for the 310 SS (irradiated as well as unirradiated) within a life factor of 2. For the titanium alloy, 95 percent of the data was predicted within a life factor of 3.

Debogdan, C. E.

1973-01-01

232

Corrosion bajo tension de acero inoxidable 304 en soluciones de tiocianato. (Corrosion under stress of AISI 304 steel in thiocyanate solutions).  

National Technical Information Service (NTIS)

Corrosion susceptibility under stress of AISI 304 steel sensitized in a sodium thiocyanate solution has been studied and results were compared with those obtained with solutions of thiosulfate and tetrathionate. Sensitized steel type 304 is highly suscept...

G. S. Duffo P. M. Perillo

1989-01-01

233

Effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and forces in finish turning of hardened AISI H13 steel  

Microsoft Academic Search

In this study, the effects of cutting edge geometry, workpiece hardness, feed rate and cutting speed on surface roughness and resultant forces in the finish hard turning of AISI H13 steel were experimentally investigated. Cubic boron nitrite inserts with two distinct edge preparations and through-hardened AISI H13 steel bars were used. Four-factor (hardness, edge geometry, feed rate and cutting speed)

Tugrul Özel; Tsu-Kong Hsu; Erol Zeren

2005-01-01

234

Effect of texture on corrosion behavior of AISI 304L stainless steel  

SciTech Connect

Electrochemical behavior of austenitic AISI 304 stainless steel in two different solutions is presented here. Effect of cold rolling conditions on corrosion behavior of the steel is studied with respect to strain-induced {alpha}'-martensite phase, residual stress, and texture of both the austenite and {alpha}'-martensite phases. The annealed steel plate has been unidirectionally cold, rolled-up to 90% reductions. X-ray diffraction (XRD) technique has been employed to quantify the volume fractions of austenite and martensite phases and to study the textural development in the steel in rolled conditions. The presence of close pack crystallographic planes parallel to the specimen surface found to improve the corrosion properties.

Ravi Kumar, B. [National Metallurgical Laboratory, Jamshedpur, 831007 Jharkhand (India)]. E-mail: ravik@nmlindia.org; Singh, Raghuvir [National Metallurgical Laboratory, Jamshedpur, 831007 Jharkhand (India); Mahato, Bhupeshwar [National Metallurgical Laboratory, Jamshedpur, 831007 Jharkhand (India); De, P.K. [National Metallurgical Laboratory, Jamshedpur, 831007 Jharkhand (India); Bandyopadhyay, N.R. [Bengal Engineering College, Howrah (India); Bhattacharya, D.K. [National Metallurgical Laboratory, Jamshedpur, 831007 Jharkhand (India)

2005-02-15

235

Residual Stress Analysis of Boronized AISI 1018 Steel by Synchrotron Radiation  

SciTech Connect

AISI 1018 steel substrates were powder-pack, diffusion boronized at 850 C for 4 h, followed by air quenching. Optical microscopy in conjunction with color etching was used to obtain the average penetration depth of the iron monoboride layer (9 {micro}m) and the iron diboride layer (57 {micro}m). X-ray diffraction by synchrotron radiation, conducted at the National Synchrotron Light Source in Brookhaven National Laboratory, confirmed the presence of iron monoboride and iron diboride in the boronized plain steel substrates. The sin{sup 2} {Psi} technique was employed to calculate the residual stress found in the iron monoboride layer (-237 MPa) and in the substrate layer (-150 MPa) that is intertwined with the needle-like, iron diboride penetration.

Payne, J A [New Jersey Insitute of Technology; Petrova, R S [New Jersey Insitute of Technology; White, H J [Stony Brook University (SUNY); Chauhan, A [Stony Brook University (SUNY); Bai, Jianming [ORNL

2008-01-01

236

Acoustic Emission Methodology to Evaluate the Fracture Toughness in Heat Treated AISI D2 Tool Steel  

NASA Astrophysics Data System (ADS)

In this article, fracture toughness behavior of tool steel was investigated using Acoustic Emission (AE) monitoring. Fracture toughness ( K IC) values of a specific tool steel was determined by applying various approaches based on conventional AE parameters, such as Acoustic Emission Cumulative Count (AECC), Acoustic Emission Energy Rate (AEER), and the combination of mechanical characteristics and AE information called sentry function. The critical fracture toughness values during crack propagation were achieved by means of relationship between the integral of the sentry function and cumulative fracture toughness (KICUM). Specimens were selected from AISI D2 cold-work tool steel and were heat treated at four different tempering conditions (300, 450, 525, and 575 °C). The results achieved through AE approaches were then compared with a methodology proposed by compact specimen testing according to ASTM standard E399. It was concluded that AE information was an efficient method to investigate fracture characteristics.

Mostafavi, Sajad; Fotouhi, Mohamad; Motasemi, Abed; Ahmadi, Mehdi; Sindi, Cevat Teymuri

2012-10-01

237

Correlation of yield strength with irradiation-induced microstructure in AISI 316 stainless steel  

SciTech Connect

Improvements in the correlation of radiation-induced change in yield strength in AISI 316 stainless steel with microstructure were made by re-examining the role of short-range obstacles. Effects due to the size of the obstacles relative to their spacing and shape of the obstacles were applied. The concept of shearing the precipitates instead of bowing around them was used to explain the effects of precipitate hardening. It is concluded that large changes in yield strength may be produced in high swelling materials. Voids will dominate the hardening at high dpa. The increase in hardening will depend on the diameter of the voids even though the swelling in the material is the same. Precipitate hardening at high fluence (>15 dpa) make a significant contribution for irradiation temperatures above 500/sup 0/C.

Simons, R.L.; Hulbert, L.A.

1985-10-01

238

Surface modification of AISI-4620 steel with intense pulsed ion beams  

NASA Astrophysics Data System (ADS)

A 300 keV, 30 kA, 1 ?s intense beam ofcarbon, oxygen, and hydrogen ions is used for the surface treatment of AISI-4620 steel coupons, a common material used in automotive gear applications. The beam is extracted from a magnetically-insulated vacuum diode and deposited into the top 1 ?m of the target surface. The beam-solid interaction causes a rapid melt and resolidification with heating and cooling rates of up to 10 10 K/s. Treated surfaces are smoothed over 1 ?m-scale lengths, but are accompanied by 1 ?m-diameter craters and larger-scale roughening over ? 10 ?m, depending on beam fluence and number of pulses. Treated surfaces are up to 1.8 × harder with no discernible change in modulus over depths of 1 ?m or more. Qualitative improvements in the wear morphology of treated surfaces are reported.

Rej, D. J.; Davis, H. A.; Nastasi, M.; Olson, J. C.; Peterson, E. J.; Reiswig, R. D.; Walter, K. C.; Stinnett, R. W.; Remnev, G. E.; Struts, V. K.

1997-05-01

239

Characteristics of Laser Beam and Friction Stir Welded AISI 409M Ferritic Stainless Steel Joints  

NASA Astrophysics Data System (ADS)

This article presents the comparative evaluation of microstructural features and mechanical properties of friction stir welded (solid-state) and laser beam welded (high energy density fusion welding) AISI 409M grade ferritic stainless steel joints. Optical microscopy, microhardness testing, transverse tensile, and impact tests were performed. The coarse ferrite grains in the base material were changed to fine grains consisting duplex structure of ferrite and martensite due to the rapid cooling rate and high strain induced by severe plastic deformation caused by frictional stirring. On the other hand, columnar dendritic grain structure was observed in fusion zone of laser beam welded joints. Tensile testing indicates overmatching of the weld metal relative to the base metal irrespective of the welding processes used. The LBW joint exhibited superior impact toughness compared to the FSW joint.

Lakshminarayanan, A. K.; Balasubramanian, V.

2012-04-01

240

Microstructural Evolution in Multiway Loading-Forming Process of AISI 5140 Steel Triple Valve Body  

NASA Astrophysics Data System (ADS)

The microstructural evolution and distribution rules, such as dynamic recrystallization (DRX) volume fraction, dynamically recrystallized grain size, and average grain size, in multiway loading-forming process of AISI 5140 steel triple valve body have been investigated using numerical simulation, combined with the analytic method by considering the influences of process parameters including loading speed of punch, initial temperature of billet, and friction. The results show that the DRX volume fraction increased, and its distribution became more uniform with the increases of punch loading speed and billet initial temperature, or the decrease of friction factor; the dynamically recrystallized grain size decreased, and its distribution was more uniform, with the increases of punch loading speed and friction factor, or the decrease of billet initial temperature; the average grain size decreased, and its distribution became more uniform with the increases of punch loading speed and billet initial temperature, or decrease of friction factor.

Sun, Zhichao; Yang, He

2014-04-01

241

On the oxide formation on stainless steels AISI 304 and incoloy 800H investigated with XPS  

NASA Astrophysics Data System (ADS)

The influence of cold work on the initially formed oxide layer on the stainless steels AISI 304 and Incology 800H has been studied by XPS. Oxidations were performed at pressures of 10 -6-10 -4 Pa and temperatures of 300-800 K. All samples showed a similar oxidation behaviour. The oxidation rates of iron and chromium are of the same order of magnitude at temperatures below 650 K. Subsequent oxidation results in an iron oxide on top of a chromium oxide layer. At temperatures above 650 K the metal surface becomes enriched in chromium, which is preferentially oxidized at these temperatures and pressures. Even prolonged oxidation does not result in an iron-rich oxide surface. Nickel has never been found in its oxidized form. The binding energy of oxygen, in the various oxide layers, is independent of the extent of oxidation and is 530.6 eV.

Langevoort, J. C.; Sutherland, I.; Hanekamp, L. J.; Gellings, P. J.

1987-04-01

242

Process mapping of laser surface modification of AISI 316L stainless steel for biomedical applications  

NASA Astrophysics Data System (ADS)

A 1.5-kW CO2 laser in pulsed mode at 3 kHz was used to investigate the effects of varied laser process parameters and resulting morphology of AISI 316L stainless steel. Irradiance and residence time were varied between 7.9 to 23.6 MW/cm2 and 50 to 167 ?s, respectively. A strong correlation between irradiance, residence time, depth of processing and roughness of processed steel was established. The high depth of altered microstructure and increased roughness were linked to higher levels of both irradiance and residence times. Energy fluence and surface temperature models were used to predict levels of melting occurring on the surface through the analysis of roughness and depth of the region processed. Microstructural images captured by the SEM revealed significant grain structure changes at higher irradiances, but due to increased residence times, limited to the laser in use, the hardness values were not improved.

Chikarakara, Evans; Naher, Sumsun; Brabazon, Dermot

2010-11-01

243

Stress-Corrosion Cracking of AISI 4340 Steel in Aqueous Environments  

NASA Astrophysics Data System (ADS)

Stress corrosion cracking of the high-strength martensitic steel AISI 4340 (yield stress = 1503 MPa) in NaCl aqueous solutions of different concentrations was studied experimentally using compact tension specimens in free corroding conditions. The experiments were conducted under the controls of constant load, constant crack opening displacement (COD), constant loading rate, and constant COD rate. Despite the differences in controlling conditions, the experiments yielded similar results for the threshold stress intensity factor and the plateau velocity in the 3.5 wt pct NaCl solution. Dependence of the plateau velocity on the NaCl concentration was observed, whereas the values of the threshold stress intensity factors seem to be independent of the NaCl concentration in distilled water.

Kalnaus, Sergiy; Zhang, Jixi; Jiang, Yanyao

2011-02-01

244

Effect of five lubricants on life of AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Spur-gear surface fatigue tests were conducted with five lubricants using a single lot of consumable-electrode vacuum melted (CVM) AISI 9310 spur gears. The lot of gears was divided into five groups, each of which was tested with a different lubricant. The test lubricants are classified as either a synthetic hydrocarbon, mineral oil, or ester-based lubricant. All five lubricants have imilar viscosity and pressure-viscosity coefficients. A pentaerythritol base stock without sufficient antiwear additives produced a surface fatigue life pproximately 22 percent that of the same base stock with chlorine and phosphorus type additives. The presence of sulfur type antiwear additives in the lubricant did not appear to affect the surface fatigue life of the gears tested. No statistical difference in the 10-percent surface fatigue life was produced with four of the five lubricants.

Townsend, D. P.; Zaretsky, E. V.

1985-01-01

245

3DII implantation effect on corrosion properties of the AISI/SAE 1020 steel  

NASA Astrophysics Data System (ADS)

The three dimensional ion implantation technology (3DII) is one of the methods of improving the tribological characteristics and resistance to hydrogen embrittlement processes in metals. In this report, some results concerning the resistance effect of nitrogen ion implantation to oxidation of the sample, made of AISI/SAE 1020 steel, are given. The nitrogen ions were implanted in the discharge chamber of the JUPITER reactor. Both the treated and untreated samples were tested through potential-static measurements, which permitted to determine the corrosion current, the slopes that characterise the braking level of anode and cathode reactions. The polarization resistance near the corrosion potential is calculated. The results of the study encourage to consider the nitrogen ion implantation in high voltage and low pressure discharges as one of the methods of anticorrosive protection which do not change the geometric configuration of the treated steel pieces.

Dulcé M., Héctor J.; Rueda v., Alejandro; Dougar-Jabon, Valeri

2005-08-01

246

ALS - resources  

MedlinePLUS

Resources - ALS ... The following organizations are good resources for information on amyotrophic lateral sclerosis : Muscular Dystrophy Association - http://mda.org/disease/amyotrophic-lateral-sclerosis National Amyotrophic Lateral Sclerosis (ALS) ...

247

Dynamic behavior analysis of drill-threading process when machining AISI Al-Si-Cu 4 alloy  

Microsoft Academic Search

Conventional threading operations involve two distinct machining processes: drilling and threading. Therefore, it is time\\u000a consuming for the tools must be changed and the workpiece has to be moved to another machine. This paper presents an analysis\\u000a of the combined process (drilling followed by threading) using a single tool for both operations: the tap-milling tool. Before\\u000a presenting the methodology used

Wisley Falco Sales; Marcelo Becker; Alexandre G. Gurgel; Jánes L. Júnior

2009-01-01

248

The effect of Al implantation on the thermal oxidation of stainless steel in aggressive environments  

SciTech Connect

AISI-321 steel samples were implanted with Al ions (implantation-energy: 40 keV; dose: 2 {times} 10{sup 17} ions/cm{sup 2}). Thermal oxidation of the samples was performed at 450, 550, 600, and 650 C for periods varying from 1 to 6 days in air and in a corrosive CO{sub 2}-containing environment. Nuclear Reaction Analysis (NRA) and Rutherford Backscattering Spectrometry (RBS) were used to investigate the oxidized samples. A significant improvement of the oxidation resistance of the implanted material in comparison to the nonimplanted material was observed. This especially applies for samples oxidized at high temperatures. The aluminum depth distribution determined by NRA [using the resonance at 992keV of the {sup 27}Al(p,{gamma}){sup 28}Si nuclear reaction] and RBS, indicated no variation of the Al profile in the temperature region 450--600 C, whereas at 650 C a slight Al diffusion was observed. Scanning electron microscopy (SEM-EDS) was applied to study the surface morphology and the constitution of the oxide scale formed, as well as to explain the influence of Al implantation of the oxidation behavior of AISI-321 austenitic stainless steel.

Noli, F.; Misaelides, P.; Giorginis, G.; Baumann, H.; Pavlidou, E.

2000-04-01

249

Observation of an adiabatic shear band in AISI 4340 steel by high-voltage transmission electron microscopy  

Microsoft Academic Search

Adiabatic shear bands, formed in a hollow AISI 4340 steel cylinder subjected to dynamic expansion by means of an explosive\\u000a charge placed in its longitudinal axis, were characterized. The adiabatic shear bands formed in this quenched and tempered\\u000a steel were of the classical “transformed” type. Scanning electron microscopy (SEM) of etched surfaces revealed that alignment\\u000a of the lamellae along the

C. L. Wittman; M. A. Meyers; H.-R. Pak

1990-01-01

250

Microstructure and mechanical properties of electron beam-welded AISI 409M-grade ferritic stainless steel  

Microsoft Academic Search

This paper deals with the microstructure and mechanical characterization of electron beam-welded AISI 409M-grade ferritic\\u000a stainless steel joints. Single-pass autogenous welds free of volumetric defects were produced at a welding speed of 1,000 mm\\/min.\\u000a The joints were subjected to optical microscopy, scanning electron fractography, microhardness, transverse and longitudinal\\u000a tensile, bend and charpy impact toughness testing. The coarse ferrite grains in the

A. K. Lakshminarayanan; V. Balasubramanian; G. Madhusudhan Reddy

2011-01-01

251

Micro-abrasion wear testing of PVD TiN coatings on untreated and plasma nitrided AISI H13 steel  

Microsoft Academic Search

An abrasive wear test, based on the ball-crater technique, has been used to evaluate the wear resistance of PVD TiN coatings, on untreated and plasma nitrided AISI H13 steels. Knoop microhardness measurements and scratch tests were carried out to characterise the coating systems under investigation. The TiN on plasma nitrided “duplex” coatings showed better micro-abrasive wear resistance than the single-layered

J. C. A Batista; M. C Joseph; C Godoy; A Matthews

2001-01-01

252

Empirical models and optimal cutting parameters for cutting forces and surface roughness in hard milling of AISI H13 steel  

Microsoft Academic Search

In the present research, an attempt has been made to experimentally investigate the effects of cutting parameters on cutting\\u000a forces and surface roughness in hard milling of AISI H13 steel with coated carbide tools. Based on Taguchi’s method, four-factor\\u000a (cutting speed, feed, radial depth of cut, and axial depth of cut) four-level orthogonal experiments were employed. Three\\u000a cutting force components

Tongchao Ding; Song Zhang; Yuanwei Wang; Xiaoli Zhu

2010-01-01

253

Influence of microstructure on the corrosion behavior of nitrocarburized AISI H13 tool steel obtained by pulsed DC plasma  

Microsoft Academic Search

The influence of microstructure on the corrosion behavior of pulsed plasma nitrocarburized AISI H13 tool steel in NaCl 0.9 wt\\/V % solution is reported. The samples were prepared with different nitrocarburizing treatment times using a constant [CH4\\/H2+N2] gaseous mixture by a DC pulsed plasma system. The microstructure of the nitrocarburized layers was analyzed by scanning electron microscopy (SEM), X-ray photoelectron spectroscopy

R. L. O. Basso; R. J. Candal; C. A. Figueroa; D. Wisnivesky; F. Alvarez

2009-01-01

254

Effects of the high temperature plasma immersion ion implantation (PIII) of nitrogen in AISI H13 steel  

Microsoft Academic Search

In this paper we report the effect of high temperature PIII of nitrogen on the chemical and physical properties of AISI H13\\u000a steel. The implantation of H13 steels was carried out at different temperatures ranging between 300 °C and 720 °C. After the\\u000a treatment, the surface morphology was drastically changed as observed by SEM analysis. Nitrogen penetration depth reaching\\u000a up to 12

L. L. G. da Silva; M. Ueda; C. B. Mello; E. N. Codaro; C. M. Lepienski

2008-01-01

255

Adhesion of reactive magnetron sputtered TIN x and TIC y coatings to AISI H13 tool steel  

Microsoft Academic Search

Reactive Magnetron Sputtered TiN and TiC films were deposited on AISI H13 tool steel and silicon (111) substrates, under nitrogen and argon or methane and argon reactive plasma. Depth sensing techniques were used to assess the mechanical properties of the films, namely hardness and Young modulus using a load of 7.0 mN. TiN and TiC were deposited using a magnetron sputtering

A. A. C. Recco; I. C. Oliveira; M. Massi; H. S. Maciel; A. P. Tschiptschin

2007-01-01

256

Evaluation of gas nitriding process with in-process variation of nitriding potential for AISI H13 tool steel  

Microsoft Academic Search

Gas nitriding under controlled nitriding potential represents one of the important factors in enhancing the service life of\\u000a dies used in the industry for hot aluminum extrusion. In the present study, AISI H13, a typical material used for hot extrusion\\u000a dies, is gas nitrided using automated two-stage controlled nitriding process. Prior heat treatment on the material was carried\\u000a out under

S. S. Akhtar; A. F. M. Arif; Bekir Sami Yilbas

2010-01-01

257

Evaluation of stress corrosion cracking phenomenon in an AISI type 316LN stainless steel using acoustic emission technique  

Microsoft Academic Search

This paper deals with the analysis of the acoustic emission (AE) signals to determine the micro-process during stress corrosion cracking (SCC) of AISI type 316LN stainless steel that cause the AE, and thus the mechanism of the SCC process. AE with amplitudes ranging from 27.6 to 46.5dB with different counts, energy and rise times occurred during SCC of type 316LN

H. Shaikh; R. Amirthalingam; T. Anita; N. Sivaibharasi; T. Jaykumar; P. Manohar; H. S. Khatak

2007-01-01

258

Deposition of titanium nitride thin films on stainless steel—AISI 304 substrates using a plasma focus device  

Microsoft Academic Search

A 3.3 kJ pulsed plasma focus device was used to deposit thin films of titanium nitride (TiN) at room temperature onto the stainless steel—AISI 304 substrates. The small plasma focus device, fitted with solid titanium anode instead of the usual hollow copper anode, was operated with nitrogen as the filling gas for deposition of TiN thin films. Films were deposited

R. S. Rawat; W. M. Chew; Paul Lee; T. White; Lee Sing

2003-01-01

259

Effects of carbon and nitrogen on the elastic constants of AISI (American Iron and Steel Institute) type 304 stainless steel  

SciTech Connect

Nine AISI type 304 stainless steel alloys were studied at room temperature. The carbon-plus-nitrogen contents of these alloys ranged from 0.067 to 0.325 wt.% (from 0.3 to 1.3 at. %). Five elastic constants (the longitudinal modulus, Young's modulus, the shear modulus, the bulk modulus and Poisson's ratio) were determined by a pulse echo ultrasonic method.

Ledbetter, H.M.; Austin, M.W.

1985-01-01

260

Effect of Cr\\/Ni equivalent ratio on ductility-dip cracking in AISI 316L weld metals  

Microsoft Academic Search

The ductility-dip cracking (DDC) susceptibility of AISI 316L stainless steel weld metals was examined. Modified flux cored arc welding (FCAW) filler wires were fabricated with various chromium and nickel contents. The solidification mode and delta-ferrite content were determined from the chromium and nickel equivalent ratios (Creq\\/Nieq). Ductility-dip cracking occurred through a grain boundary sliding mechanism in the reheated region of

A. Y. Jang; D. J. Lee; S. H. Lee; J. H. Shim; S. W. Kang; H. W. Lee

2011-01-01

261

Effect of temperature and strain distribution on martensitic transformation during uniaxial testing of AISI304 stainless steel  

Microsoft Academic Search

A coupled finite element method has been used to determine the true plastic strain, effective strain, and temperature distribution\\u000a inside the tensile specimen of AISI-304 austenitic stainless steel during uniaxial testing at low and high strain rates. The\\u000a volume fraction of martensite has been computed along the gage length by employing Olson-Cohen analysis and using the value\\u000a of a and

Ashok Kumar; L. K. Singhal

1988-01-01

262

Evaluation of the joint-interface properties of austenitic-stainless steels (AISI 304) joined by friction welding  

Microsoft Academic Search

The aim of this study is to investigate experimentally the micro-structural properties and welding strengths of the joints using austenitic-stainless steel (AISI 304) parts. The experiments were carried out using a beforehand designed and constructed experimental friction welding set-up, constructed as continuous-drive. Firstly, pilot welding experiments under different friction time and friction pressure were carried out to obtain optimum parameters

Mumin Sahin

2007-01-01

263

Modification of AISI M2 high-speed tool steels after laser-surface melting under different operating conditions  

Microsoft Academic Search

We applied a laser-surface melting treatment to AISI M2 high-speed steel – hardened and tempered – and studied the resulting surface characteristics (microstructure) and mechanical behaviour (hardness and wear performance). The steel was treated using a Nd:YAG continuous-wave laser with different operation conditions. The influence of the laser processing parameters on the individual beads and on the characteristics of the

J. Arias; M. Cabeza; G. Castro; I. Feijoo; P. Merino; G. Pena

2011-01-01

264

High current density, low energy, ion implantation of AISI-M2 tool steel for tribological applications  

Microsoft Academic Search

The effects of the temperatures of fully hardened and mill-annealed AISI M2 steels during N implantation at low energy and high current density on their hardnesses, sliding wear behaviors, microstructures and N concentration profiles were investigated. It is shown that N implantation at 1 keV and 2 mA cm?2 can increase the hardness of the steel in either condition, but

P. J. Wilbur; J. A. Davis; R. Wei; J. J. Vajo; D. L. Williamson

1996-01-01

265

Application of response surface methodology for determining cutting force model in turning hardened AISI H11 hot work tool steel  

Microsoft Academic Search

.  This experimental study is conducted to determine statistical models of cutting forces in hard turning of AISI H11 hot work\\u000a tool steel (? 50 HRC). This steel is free from tungsten on Cr–Mo–V basis, insensitive to temperature changes and having a\\u000a high wear resistance. It is employed for the manufacture of highly stressed diecasting moulds and inserts with high tool life

B FNIDES; M A YALLESE; T MABROUKI; J-F RIGAL

2011-01-01

266

Mechanical properties and microstructural features of AISI 4340 high-strength alloy steel under quenched and tempered conditions  

Microsoft Academic Search

In this work, the mechanical properties and microstructures of AISI 4340 high strength alloy steel under different tempering conditions are investigated. The specimens are quenched and tempered to a martensite structure and loaded to fracture at a constant strain-rate of 3.3×10?4 s?1 by means of a dynamic material testing machine (MTS 810). The mechanical properties and strain-hardening exponent are considered

Woei-Shyan Lee; Tzay-Tian Su

1999-01-01

267

Fatigue behavior of a quenched and tempered AISI 4340 steel coated with an electroless NiP deposit  

Microsoft Academic Search

The fatigue life of a quenched and tempered AISI 4340 steel has been evaluated in three different conditions: (a) uncoated, (b) coated with an electroless Ni-P (EN) deposit of a P content of approximately 12–14wt.%, as-deposited and (c) as-deposited, followed by a two-step post-heat treatment (PHT): 473 K for 1 h plus 673 K for 1 h. The results indicate

Y. Garcés; H. Sánchez; J. Berr??os; A. Pertuz; J. Chitty; H. Hintermann; E. S. Puchi

1999-01-01

268

On the fatigue behavior of an AISI 316L stainless steel coated with a PVD TiN deposit  

Microsoft Academic Search

The effect of a TiN coating on the fatigue properties of an AISI 316L stainless steel has been investigated. The coating was approximately 1.4-?m thick and was deposited by means of filtered cathodic arc deposition. It has been determined that the application of such a coating to the steel substrate gives rise to a significant increase in both fatigue life

E. S Puchi-Cabrera; F Mat??nez; I Herrera; J. A Berr??os; S Dixit; D Bhat

2004-01-01

269

Improvement of fatigue life of electrical discharge machined AISI D2 tool steel by TiN coating  

Microsoft Academic Search

This work presents the effects of titanium nitride (TiN) coating by physical vapor deposition (PVD) on the fatigue life of AISI D2 tool steel, which was electrical discharge machined (EDM) at various machining parameters, such as pulse current and pulse-on duration. Surface hardness, surface roughness, residual stress and fatigue strength were measured. Experimental results indicate that EDM treatment has a

Y. H. Guu; H. Hocheng

2001-01-01

270

Evolving mechanism of eutectic carbide in as-cast AISI M2 high-speed steel at elevated temperature  

Microsoft Academic Search

The evolution in type, size and shape of carbides in as-cast American Iron and Steel Institute (AISI) M2 high-speed steel\\u000a before and after annealing were investigated. The micromechanism which was responsible for those changes was also analyzed\\u000a and discussed. At the initial stage of reheating, metastable M2C-type carbide decomposed continuously. M6C-type carbide nucleated at the interface of M2C\\/? firstly and

Bin Zhou; Yu Shen; Jun Chen; Zhen-shan Cui

2010-01-01

271

Process parameters selection for laser polishing DF2 (AISI O1) by Nd:YAG pulsed laser using orthogonal design  

Microsoft Academic Search

Mechanisms of laser polishing metals in a continuous scanning mode, as envisaged and analyzed in this paper, are rather complex,\\u000a and experimental optimization of laser polishing metallic material is very time-consuming and difficult. Aiming at shortening\\u000a the experimental time in achieving a better surface finishing of DF2 (AISI 01) tool steel by pulse Nd:YAG laser, we used the\\u000a orthogonal experimental

Wei Guo; Meng Hua; Peter Wai-Tat Tse; Albert Chiu Kam Mok

272

Improvement of corrosion and wear resistances of AISI 420 martensitic stainless steel using plasma nitriding at low temperature  

Microsoft Academic Search

The influence of low temperature plasma nitriding on the wear and corrosion resistance of AISI 420 martensitic stainless steel was investigated. Plasma nitriding experiments were carried out with DC-pulsed plasma in 25% N2+75% H2 atmosphere at 350 °C, 450 °C and 550 °C for 15 h. The composition, microstructure and hardness of the nitrided samples were examined. The wear resistances of plasma nitrided samples

Yun-tao Xi; Dao-xin Liu; Dong Han

2008-01-01

273

A zirconia-polyester glycol coating on differently pretreated AISI 316L stainless steel: corrosion behavior in chloride solution  

Microsoft Academic Search

The effect of zirconia and zirconia-polyester glycol hybrid coatings on the corrosion resistance of mechanically polished\\u000a or anodized AISI 316 stainless steel (316L), was studied by potentiodynamic polarization and electrochemical impedance spectroscopy\\u000a in 0.1 M NaCl and scanning electron microscope and atomic force microscopy examinations. The deposition of zirconia coatings\\u000a was achieved by the sol–gel technique by immersing the samples in

C. Martinez; M. Sancy; J. H. Zagal; F. M. Rabagliati; B. Tribollet; H. Torres; J. Pavez; A. Monsalve; M. A. Paez

2009-01-01

274

A study on the stability of AISI 316L stainless steel pitting corrosion through its transfer function  

Microsoft Academic Search

Impedance measurements were made on an electrochemically polarized AISI 316L stainless steel in a 5% NaCl solution at room temperature. Limited information about this electrochemical method is available in the literature. Three polarization sweep rates, 0.10, 0.30 and 0.40 mVs?1 were tested. Nyquist plots at the pitting potential regions show three capacitive loops. A deconvolution method combined with a complex

J. M Bastidas; J. L Polo; C. L Torres; E Cano

2001-01-01

275

Effect of metallurgical variables on the stress corrosion crack growth behaviour of AISI type 316LN stainless steel  

Microsoft Academic Search

Mill-annealed AISI type 316LN stainless steels, received from two different sources (one indigenous (SS-2) and the other foreign (SS-1)), were tested for stress corrosion cracking (SCC) resistance in a boiling acidified environment of NaCl. SCC results indicated a remarkably lower value of plateau crack growth rate (PCGR) and higher values of KISCC and JISCC for SS-2, which was attributed to

H. Shaikh; T. Anita; R. K. Dayal; H. S. Khatak

2010-01-01

276

The plastic deformation behaviour of AISI 4340 alloy steel subjected to high temperature and high strain rate loading conditions  

Microsoft Academic Search

The purpose of this study is to investigate the deformation behaviour of AISI 4340 alloy steel under high strain rates ranging from 500 to 3300 s?1 and at constant temperatures in the range of 25–1100°C by means of a split Hopkinson bar. The tested temperatures are obtained by enclosing the specimen in a clam-shell radiant-furnace. The S.E.M. and T.E.M. techniques

Woei-Shyan Lee; Gen-Wang Yeh

1997-01-01

277

Effect of coatings obtanied by sputtering of chromium catode on the corrosion resistance of AISI H13 steel  

NASA Astrophysics Data System (ADS)

Corrosion resistance of coatings obtained by sputtering a chromium target were evaluated. The films were deposited on substrates of disk-shaped AISI H13 steel. By means of potentiodynamic polarization curves were able to determine the current density vs. potential for the coated and uncoated substrate and the difference in the corrosion potential Ecorr. All samples with coating showed an increase in Ecorr respect to substrate. The electrochemical tests were conducted in an electrolytic solution of 3% NaCl.

Sandoval, A.; Peña, D.; Piratoba, U.

2013-11-01

278

Corrosion resistance properties of glow-discharge nitrided AISI 316L austenitic stainless steel in NaCl solutions  

Microsoft Academic Search

Glow-discharge nitriding treatments can modify the hardness and the corrosion resistance properties of austenitic stainless steels. The modified layer characteristics mainly depend on the treatment temperature. In the present paper the results relative to glow-discharge nitriding treatments carried out on AISI 316L austenitic stainless steel samples at temperatures ranging from 673 to 773K are reported. Treated and untreated samples were

A. Fossati; F. Borgioli; E. Galvanetto; T. Bacci

2006-01-01

279

Improvement of erosion and erosion corrosion resistance of AISI420 stainless steel by low temperature plasma nitriding  

NASA Astrophysics Data System (ADS)

Plasma nitriding experiments were carried out with DC-pulsed plasma in 25% N 2 + 75% H 2 atmosphere at low temperature (350 °C) and normal temperature (550 °C) for 15 h. The composition, microstructure, microhardness profiles, residual stress profiles and electrochemical impedance spectrum analyses of the nitrided samples were examined. The influence of plasma nitriding on the erosion and erosion-corrosion resistance of AISI 420 martensitic stainless steel was investigated using a jet solid particle erosion tester and a slurry erosion-corrosion tester. Results showed that the 350 °C nitriding layer was dominated by ?-Fe 3N and ? N phase, a supersaturated nitrogen solid solution. However, nitrogen would react with Cr in the steel to form CrN precipitates directly during 550 °C nitriding, which would lead to the depletion of Cr in the solid solution phase of the nitrided layer. Both 350 and 550 °C plasma nitriding could improve the erosion resistance of AISI420 stainless steel under dry erosion, but the former showed better results. In both neutral and acid environment, while the erosion-corrosion resistance of AISI 420 was improved by means of 350 °C nitriding, it was decreased through 550 °C nitriding.

Xi, Yun-tao; Liu, Dao-xin; Han, Dong

2008-07-01

280

Tribological Characteristics of Single-phase AlMgB14 and Nanocomposite AlMgB14-TiB2 Superhard Coatings  

SciTech Connect

This study investigated the friction and wear characteristics of AlMgB14 and AlMgB14-TiB2 superhard coatings, produced by pulse laser deposition (PLD) and physical vapor deposition (PVD), respectively. Tests were conducted under unidirectional and reciprocating sliding against AISI 52100 bearing steel in both dry and oil-lubricated conditions. The AlMgB14 coating exhibited an encouraging but short-lived low friction stage (u = 0.2) in dry sliding. The AlMgB14-TiB2 coating reduced the wear rates by one order of magnitude for itself and three orders of magnitude for the counterface compared with the uncoated M2 tool steel in dry sliding. This nanocomposite coating also demonstrated significant extension (>2.5X) of the low friction (non-scuffing) stage in a lubricant starvation sliding.

Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Zhu, Dong [Eaton Corporation; Cook, Bruce A [Ames Laboratory; Elmoursi, Alaa A [Eaton Corporation

2008-01-01

281

Substrate bias effects on mechanical and tribological properties of substitutional solid solution (Ti, Al)N films prepared by reactive magnetron sputtering  

Microsoft Academic Search

Nitrogen-saturated solid solution titanium–aluminium–nitride (Ti, Al)N thin films were deposited onto Si(100) wafers (for concentration and mechanical analyses) and AISI M42 tool steels (for tribological measurements) at room temperature by reactive close-field unbalanced magnetron sputtering in an Ar–N2 gas mixture. The effects of substrate negative bias voltages (Ub) on the mechanical and tribological properties of these films have been studied.

K. Chu; P. W. Shum; Y. G. Shen

2006-01-01

282

Friction and wear properties of carbon fabric composites filled with nano-Al 2O 3 and nano-Si 3N 4  

Microsoft Academic Search

The carbon fabric composites filled with the particulates of nano-Al2O3 and nano-Si3N4, respectively, were prepared by dip-coating of the carbon fabric in a phenolic resin containing the particulates to be incorporated and successive curing. The friction and wear behaviors of the resulting carbon fabric composites sliding against AISI-1045 steel in a pin-on-disk configuration were evaluated on a Xuanwu-III high temperature

Feng-Hua Su; Zhao-Zhu Zhang; Kun Wang; Wei Jiang; Xue-Hu Men; Wei-Min Liu

2006-01-01

283

Investigations on friction and wear mechanisms of the PVD-TiAlN coated carbide in dry sliding against steels and cast iron  

Microsoft Academic Search

The tribological behaviour of the monolayer PVD-titanium aluminium nitride (TiAlN) coated carbide inserts in unidirectional dry sliding against steel and cast iron counterparts was investigated using the pin-on-disc standard test with varying sliding speeds and normal loads. Three different materials of various machinability rates were used as the counterparts, namely the normalised medium carbon steel C45 equivalent to AISI 1045,

W. Grzesik; Z. Zalisz; S. Krol; P. Nieslony

2006-01-01

284

Wear resistance of TiAlSiN thin coatings.  

PubMed

In the last decades TiAIN coatings deposited by PVD techniques have been extensively investigated but, nowadays, their potential development for tribological applications is relatively low. However, new coatings are emerging based on them, trying to improve wear behavior. TiAlSiN thin coatings are now investigated, analyzing if Si introduction increases the wear resistance of PVD films. Attending to the application, several wear test configurations has been recently used by some researchers. In this work, TiAISiN thin coatings were produced by PVD Unbalanced Magnetron Sputtering technique and they were conveniently characterized using Scanning Electron Microscopy (SEM) provided with Energy Dispersive Spectroscopy (EDS), Atomic Force Microscopy (AFM), Electron Probe Micro-Analyzer (EPMA), Micro Hardness (MH) and Scratch Test Analysis. Properties as morphology, thickness, roughness, chemical composition and structure, hardness and film adhesion to the substrate were investigated. Concerning to wear characterization, two very different ways were chosen: micro-abrasion with ball-on-flat configuration and industrial non-standardized tests based on samples inserted in a feed channel of a selected plastic injection mould working with 30% (wt.) glass fiber reinforced polypropylene. TiAISiN coatings with a small amount of about 5% (wt.) Si showed a similar wear behavior when compared with TiAIN reported performances, denoting that Si addition does not improve the wear performance of the TiAIN coatings in these wear test conditions. PMID:23447962

Silva, F J G; Martinho, R P; Alexandre, R J D; Baptista, A P M

2012-12-01

285

Surface Modification of AISI-4620 Steel With Intense Pulsed Ion Beams  

SciTech Connect

A 300-keV, 30-kA, 1-{micro}s intense beam of carbon, oxygen, and hydrogen ions is used for the surface treatment of AISI-4620 steel coupons, a common material used in automotive gear applications. The beam is extracted from a magnetically-insulated vacuum diode and deposited into the top 1 {micro}m of the target surface. The beam-solid interaction causes a rapid melt and resolidification with heating and cooling rates of up to 10{sup 10} K/sec. Treated surfaces are smoothed over 1-{micro}m scale-lengths, but are accompanied by 1-{micro}m diameter craters and larger-scale roughening over >=10 {micro}m, depending on beam fluence and number of pulses. Treated surfaces are up to 1.8 x harder with no discernible change in modulus over depths of 1 {micro}m or more Qualitative improvements in the wear morphology of treated surfaces are reported.

Rej, D.J.; Davis, H.A.; Nastasi, M.; Olson, J.C.; Peterson, E.J.; Reiswig, R.D.; Walter, K.C.; Stinnett, R.W.; Remnev, G.E.; Struts, V.K.

1996-09-01

286

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears  

NASA Technical Reports Server (NTRS)

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semi-logarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

287

Study of microstructure of low-temperature plasma-nitrided AISI 304 stainless steel  

SciTech Connect

The microstructure of the low-temperature plasma-nitrided layer on AISI 304 austenitic stainless steel was studied by transmission electron microscopy (TEM). The results show that the surface of the layer consists of a supersaturated solid solution ({gamma}{prime}{sub N}) based on the {gamma}{prime}-Fe{sub 4}N phase whose electron diffraction pattern (EDP) has a strong diffuse scattering effect resulting from supersaturating nitrogen (above 20 at. pct) and {l_angle}110{r_angle} streaks arising from matrix elastic strain due to the formation of paired or clustered Cr-N. The latter is due to the N above to 20 at. pct {gamma}{prime}-Fe{sub 4}N-phase value and leads to a lattice parameter that is greater than that of the {gamma}{prime}-Fe{sub 4}N phase. The subsurface of the layer is composed of a supersaturated solid solution based on {gamma}-austenite, which is an expanded austenite, {gamma}{sub N}. Its morphology shows the basketweave or tweedlike contrast consisting of so-called stacking fault precipitates having twin relationships with the matrix whose EDP shows diffuse scattering streaks with certain directions. The {epsilon} martensite transformation was observed in the subsurface of the layer. The increase in stacking faults compared with the original stainless steel and formation of {epsilon} martensite in the subsurface of the layer indicate that nitrogen lowers the stacking fault energy of austenite.

Xu, X.; Wang, L.; Yu, Z.; Qiang, J.; Hei, Z.

2000-04-01

288

Fe-Based Amorphous Coatings on AISI 4130 Structural Steel for Corrosion Resistance  

NASA Astrophysics Data System (ADS)

The current study focuses on synthesizing a novel functional coating for corrosion resistance applications, via laser surface alloying. The iron-based (Fe48Cr15Mo14Y2C15B) amorphous precursor powder is used for laser surface alloying on AISI 4130 steel substrate, with a continuous wave ytterbium Nd-YAG fiber laser. The corrosion resistance of the coatings is evaluated for different processing conditions. The microstructural evolution and the response of the microstructure to the corrosive environment is studied using x-ray diffraction, scanning electron microscopy, and transmission electron microscopy. Microstructural studies indicate the presence of face-centered cubic Fe-based dendrites intermixed within an amorphous matrix along with fine crystalline precipitates. The corrosion resistance of the coatings decrease with an increase in laser energy density, which is attributed to the precipitation and growth of chromium carbide. The enhanced corrosion resistance of the coatings processed with low energy density is attributed to the self-healing mechanism of this amorphous system.

Katakam, Shravana; Santhanakrishnan, S.; Dahotre, Narendra B.

2012-06-01

289

An experimental investigation of pulsed laser-assisted machining of AISI 52100 steel  

NASA Astrophysics Data System (ADS)

Grinding and hard turning are widely used for machining of hardened bearing steel parts. Laser-assisted machining (LAM) has emerged as an efficient alternative to grinding and hard turning for hardened steel parts. In most cases, continuous-wave lasers were used as a heat source to cause localized heating prior to material removal by a cutting tool. In this study, an experimental investigation of pulsed laser-assisted machining of AISI 52100 bearing steel was conducted. The effects of process parameters (i.e., laser mean power, pulse frequency, pulse energy, cutting speed and feed rate) on state variables (i.e., material removal temperature, specific cutting energy, surface roughness, microstructure, tool wear and chip formation) were investigated. At laser mean power of 425 W with frequency of 120 Hz and cutting speed of 70 m/min, the benefit of LAM was shown by 25% decrease in specific cutting energy and 18% improvement in surface roughness, as compared to those of the conventional machining. It was shown that at constant laser power, the increase of laser pulse energy causes the rapid increase in tool wear rate. Pulsed laser allowed efficient control of surface temperature and heat penetration in material removal region. Examination of the machined subsurface microstructure and microhardness profiles showed no change under LAM and conventional machining. Continuous chips with more uniform plastic deformation were produced in LAM.

Panjehpour, Afshin; Soleymani Yazdi, Mohammad R.; Shoja-Razavi, Reza

2014-11-01

290

Prediction of Cutting Forces Using ANNs Approach in Hard Turning of AISI 52100 steel  

SciTech Connect

In this study, artificial neural networks (ANNs) was used to predict cutting forces in the case of machining the hard turning of AISI 52100 bearing steel using cBN cutting tool. Cutting forces evolution is considered as the key factors which affect machining. Predicting cutting forces evolution allows optimizing machining by an adaptation of cutting conditions. In this context, it seems interesting to study the contribution that could have artificial neural networks (ANNs) on the machining forces prediction in both numerical and experiment studies. Feed-forward multi-layer neural networks trained by the error back-propagation (BP) algorithm are used. Levenberg-Marquardt (LM) optimization algorithm was used for finding out weights. The training of the network is carried out with experimental machining data.The input dataset used are cutting speed, feed rate, cutting depth and hardness of the material. The output dataset used are cutting forces (Ft-cutting force, Fa- feed force and Fr- radial force).Results of the neural networks approach, in comparison with experimental data are discussed in last part of this paper.

Makhfi, Souad [Laboratoire des Technologies Industrielles. Universite Ibn Khaldoun de Tiaret, B.P. 78, Tiaret 14000 (Algeria); Laboratoire des Technologies Innovantes E.A. 3899. I.U.T. GMP-Universite de Picardie Jules Verne, avenue des Facultes, Le Bailly, 80025 Amiens Cedex1 (France); Habak, Malek; Velasco, Raphael [Laboratoire des Technologies Innovantes E.A. 3899. I.U.T. GMP-Universite de Picardie Jules Verne, avenue des Facultes, Le Bailly, 80025 Amiens Cedex1 (France); Haddouche, Kamel; Vantomme, Pascal [Laboratoire des Technologies Industrielles. Universite Ibn Khaldoun de Tiaret, B.P. 78, Tiaret 14000 (Algeria)

2011-05-04

291

Microstructural features of hot pressure bonding between stainless steel type AISI-304 L and Zircaloy-2  

NASA Astrophysics Data System (ADS)

The diffusion zone formed after reaching quasi-equilibrium in hot pressure bonding between stainless steel type AISI-304 L and Zircaloy-2 under particular thermal and compressive conditions (1000-1100°C and 2-3 atm) contains two distinct layers, each separately localized in the modified stainless steel and Zircaloy matrices. SEM, TEM, X-ray diffraction and microanalysis were used to identify the phase structure and composition of the two diffusion layers. The nature and distribution of phases found in the diffusion layers can be explained in connection with the diffusion mechanisms operating after the initial stages of bond formation and interface disappearance: (a) The strong zirconium diffusion promotes ferrite and ZrCr 2 formation in a narrow zone located near the stainless steel matrix, (b) Iron and nickel diffusion over large distances in the Zircaloy matrix leads to the occurrence of a larger zone having a two-phase structure. The light grey phase consists of untransformed ?-Zr and a small percentage of high-temperature ?-Zr phase. The darker grey phase contains essentially a very high amount of intermetallic bct compounds Zr-Fe-Ni, Zr 2Fe and Zr 2Ni dispersed in the small residue of Zircaloy matrix.

Lucuta, P. Gr.; P?tru, I.; Vasiliu, F.

1981-09-01

292

Effect of two synthetic lubricants on life of AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Spur-gear fatigue tests were conducted with two lubricants using a single lot of consumable-electrode vacuum-melted (CVM) AISI 9310 spur gears. The gears were case carburized and hardened to Rockwell C60. The gear pitch diameter was 8.89 cm. The lot of gears was divided into two groups, each of which was tested with a different lubricant. The test lubricants can be classified as synthetic polyol-ester-based lubricants. One lubricant was 30 percent more viscous that the other. Both lubricants have similar pressure viscosity coefficients. Test conditions included a bulk gear temperature of 350 K, a maximum Hertz stress of 1.71 GPa at the pitch line, and a speed of 10,000 rpm. The surface fatigue life of gears tested with one lubricant was approximately 2.4 times that for gears tested with the other lubricant. The lubricant with the 30 percent higher viscosity gave a calculated elastohydrodynamic (EHD) film thickness that was 20 percent higher than the other lubricant. This increased EHD film thickness is the most probable reason for the improvement in surface fatigue life of gears tested with this lubricant over gears tested with the less viscous lubricant.

Townsend, Dennis P.; Shimski, John

1991-01-01

293

Characterization of irradiated AISI 316L stainless steel disks removed from the Spallation Neutron Source  

SciTech Connect

Irradiated AISI 316L stainless steel disks were removed from the Spallation Neutron Source (SNS) for post-irradiation examination (PIE) to assess mechanical property changes due to radiation damage and erosion of the target vessel. Topics reviewed include high-resolution photography of the disk specimens, cleaning to remove mercury (Hg) residue and surface oxides, profile mapping of cavitation pits using high frequency ultrasonic testing (UT), high-resolution surface replication, and machining of test specimens using wire electrical discharge machining (EDM), tensile testing, Rockwell Superficial hardness testing, Vickers microhardness testing, scanning electron microscopy (SEM), and energy dispersive spectroscopy (EDS). The effectiveness of the cleaning procedure was evident in the pre- and post-cleaning photography and permitted accurate placement of the test specimens on the disks. Due to the limited amount of material available and the unique geometry of the disks, machine fixturing and test specimen design were critical aspects of this work. Multiple designs were considered and refined during mock-up test runs on unirradiated disks. The techniques used to successfully machine and test the various specimens will be presented along with a summary of important findings from the laboratory examinations.

Vevera, Bradley J [ORNL] [ORNL; Hyres, James W [ORNL] [ORNL; McClintock, David A [ORNL] [ORNL; Riemer, Bernie [ORNL] [ORNL

2014-01-01

294

Prediction of Cutting Forces Using ANNs Approach in Hard Turning of AISI 52100 steel  

NASA Astrophysics Data System (ADS)

In this study, artificial neural networks (ANNs) was used to predict cutting forces in the case of machining the hard turning of AISI 52100 bearing steel using cBN cutting tool. Cutting forces evolution is considered as the key factors which affect machining. Predicting cutting forces evolution allows optimizing machining by an adaptation of cutting conditions. In this context, it seems interesting to study the contribution that could have artificial neural networks (ANNs) on the machining forces prediction in both numerical and experiment studies. Feed-forward multi-layer neural networks trained by the error back-propagation (BP) algorithm are used. Levenberg-Marquardt (LM) optimization algorithm was used for finding out weights. The training of the network is carried out with experimental machining data. The input dataset used are cutting speed, feed rate, cutting depth and hardness of the material. The output dataset used are cutting forces (Ft-cutting force, Fa- feed force and Fr- radial force). Results of the neural networks approach, in comparison with experimental data are discussed in last part of this paper.

Makhfi, Souâd; Habak, Malek; Velasco, Raphael; Haddouche, Kamel; Vantomme, Pascal

2011-05-01

295

Influence of prior deformation on the sensitization of AISI Type 316LN stainless steel  

NASA Astrophysics Data System (ADS)

The sensitization behaviour of a nuclear grade AISI 316LN stainless steel (SS) was studied for various cold-work levels ranging from 0% (mill-annealed) to 25% reduction in thickness. ASTM standard A262 Practices A and E were adopted to detect the susceptibility to intergranular corrosion. The results obtained in these tests were used to construct time-temperature-sensitization (TTS) diagrams. Using these data, the critical linear cooling rate was calculated, above which there is no risk of sensitization. In order to predict the sensitization behaviour during practical cooling conditions, Continuous-cooling-sensitization (CCS) diagrams were established utilising the TTS diagrams by a mathematical method. The influences of prior deformation and nitrogen in the alloy on the sensitization kinetics are discussed. It was found that nitrogen addition retards the sensitization kinetics and that tmin (minimum time required for sensitization at nose temperature) increases by two orders of magnitude in Type 316LN SS compared to that of Type 316 SS at the different prior deformation levels. Cold-working up to 15% accelerates the onset of carbide precipitation and on further cold working there is not much difference in the kinetics. Desensitization is faster in highly cold-worked material, especially at high temperatures.

Parvathavarthini, N.; Dayal, R. K.; Gnanamoorthy, J. B.

1994-02-01

296

Low- Temperature improvement of mechanical properties of aisi 4340 steel through high-temperature thermomechanical treatment  

NASA Astrophysics Data System (ADS)

The low-temperature mechanical properties of AISI 4340 ultrahigh-strength steel can be dramatically improved by high-temperature thermomechanical treatment (HTMT). A comparison was made with the mechanical properties developed by the conventional heat-treatment (CHT). When the steel was hot forged by 50 pct reduction at 1177 K followed by direct oil quenching and subsequent tempering at 423 K, the slow-bending fracture energy of fatigue-precracked steels was significantly improved, with notably increased strength, owing to a moderate increase in ductility over the temperature range of 123 to 293 K, and the ductile-to-brittle transition temperature (DBTT) in the Charpy impact test was remarkably lowered. The marked development was achieved in the slow-bending fracture energy, with moderate improvement in strength, owing to significantly increased ductility over the temperature range of 123 to 293 K, when the steel was deformed by 50 pct reduction at 1473 K followed by direct oil quenching and subsequent tempering at 453 K. The treatment also improved the shelf energy and DBTT in the Charpy impact test. The improved mechanical properties are attributed to the subcell structure introduced in austenite by processing HTMT and inherited by martensite. The present work shows that an HTMT steel is attractive for low-temperature ultrahigh-strength applications when suitable combinations of deformation temperatures with tempering conditions are applied to the steels.

Tomita, Yoshiyuki

1991-05-01

297

Influence of post irradiation annealing on the mechanical properties and defect structure of AISI 304 steel  

NASA Astrophysics Data System (ADS)

The effect of post irradiation annealing on the mechanical properties and the radiation induced defect structure was investigated on stainless steel, of type AISI 304, that was irradiated up to 24 dpa in the decommissioned Chooz A reactor. The material was investigated both in the as-irradiated state as well as after post irradiation annealing. In the as-irradiated specimen the typical radiation induced defects were found as well as ?'-precipitates (Ni 3Si). Annealing at 400 °C had almost no effect on the radiation induced defects, but annealing at 500 °C resulted in the immediate unfaulting of the Frank loops. As to the mechanical properties, annealing at 400 °C did not strongly affect the yield strength and the ductility of the material, although the fraction of intergranular fracture during slow strain rate tensile tests under pressurised water reactor conditions, was significantly reduced. Annealing at 500 °C did reduce the yield strength and restored substantially the ductility and the strain hardening capability of the material. The microstructure investigated by transmission electron microscopy correlates to the mechanical test results. It was found that the observed defect changes after post irradiation annealing provide a reasonable explanation for the observed changes of the mechanical properties.

Van Renterghem, W.; Al Mazouzi, A.; Van Dyck, S.

2011-06-01

298

Effect of Hydrogen and Magnetic Field on the Mechanical Behavior of High Strength AISI 4340 Steel  

NASA Astrophysics Data System (ADS)

Presence of hydrogen in materials is known to affect their mechanical properties due to hydrogen embrittlement problem. Steels used in various applications are prone to be exposed to aqueous electrochemical environments, which may introduce hydrogen into the alloy. These alloys are also prone to be simultaneously exposed to magnetic field, which may affect the hydrogen embrittlement susceptibility of these alloys. Therefore, it is important to examine the effect of hydrogen and magnetic field on the mechanical behavior of iron-based alloys. In this work, the effect of hydrogen and magnetic field on the fracture behavior of high strength AISI 4340 steel was examined. Three-point bend test was used to study the fracture behavior. In all the cases, the samples tested with hydrogen charging show a drastic reduction in ductility and fracture stress values. The effect of magnetic field was seen to be negligible. The hydrogen embrittlement was characterized by a change in the fracture surface from a ductile-type fracture to a brittle cleavage-type fracture. Acoustic emission signals collected during the test corresponds to the fracture behavior.

Ramanathan, Meenakshisundaram; Saha, Biswadeep; Ren, Chai; Guruswamy, Sivaraman; McCarter, Michael

2013-04-01

299

Carburization behavior of AISI 316LN austenitic stainless steel - Experimental studies and modeling  

NASA Astrophysics Data System (ADS)

AISI type 316LN austenitic stainless steel was exposed to flowing sodium at 798 K for 16,000 h in the bi-metallic (BIM) sodium loop. A modified surface layer of 10 ?m width having a ferrite structure was detected from X-ray diffraction and electron micro probe based analysis. Beneath the modified surface layer a carburized zone of 60 ?m width was identified which was found to consist of M 23C 6 carbides. A mathematical model based on finite difference technique was developed to predict the carburization profiles in sodium exposed austenitic stainless steel. In the computation, effect of only chromium on carbon diffusion was considered. Amount of carbon remaining in solution was determined from the solubility parameter. The predicted profile showed a reasonably good match with the experimental profile. Calculations were extended to simulate the thickness of the carburized layer after exposure to sodium for a period of 40 years. Attempt was also made to predict the carburization profiles based on equilibrium calculations using Dictra and Thermocalc which contain both thermodynamic and kinetic databases for the system under consideration.

Sudha, C.; Sivai Bharasi, N.; Anand, R.; Shaikh, H.; Dayal, R. K.; Vijayalakshmi, M.

2010-07-01

300

The Meta-Lax method of stress reduction in welds. [ASTM A36; AISI 4140  

SciTech Connect

This study is the second phase of ongoing research into the mechanics and feasibility of using the Meta-Lax method of vibratory stress relief in place of thermal methods of stress relief. The first phase of this research revealed results that were similar to, and even superior to those achieved using thermal methods. The testing here was designed to eliminate the effects of interbead tempering by utilizing single pass bead-on-plate welds only. A metallurgical explanation for the success of the Meta-Lax method was not found. No significant structure or chemical changes were noted when used with ASTM A36 or AISI 4140 materials, and the phenomena noted in phase I was apparently due to interbead tempering. The theory of accelerated aging has been proposed and studies exist which observed dislocation motion as a result of vibratory treatment. It is evident that the vibratory stress relief system does not impart sufficient energy to bring about the magnitude of change seen with thermal methods. however the physical improvement is a reality, and vibratory methods should be evaluated further.

Smith, S.M.

1992-07-31

301

Spinodal decomposition in AISI 316L stainless steel via high-speed laser remelting  

NASA Astrophysics Data System (ADS)

A 1.5 kW CO2 pulsed laser was used to melt the surface of AISI 316L stainless steel with a view to enhancing the surface properties for engineering applications. A 90 ?m laser beam spot size focused onto the surface was used to provide high irradiances (up to 23.56 MW/cm2) with low residence times (as low as 50 ?s) in order to induce rapid surface melting and solidification. Variations in microstructure at different points within the laser treated region were investigated. From this processing refined lamellar and nodular microstructures were produced. These sets of unique microstructures were produced within the remelted region when the highest energy densities were selected in conjunction with the lowest residence times. The transformation from the typical austenitic structure to much finer unique lamellar and nodular structures was attributed to the high thermal gradients achieved using these selected laser processing parameters. These structures resulted in unique characteristics including elimination of cracks and a reduction of inclusions within the treated region. Grain structure reorientation between the bulk alloy and laser-treated region occurred due to the induced thermal gradients. This present article reports on microstructure forms resulting from the high-speed laser surface remelting and corresponding underlying kinetics.

Chikarakara, Evans; Naher, Sumsun; Brabazon, Dermot

2014-05-01

302

Thermodynamic modeling and kinetics simulation of precipitate phases in AISI 316 stainless steels  

NASA Astrophysics Data System (ADS)

This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 °C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.

Yang, Y.; Busby, J. T.

2014-05-01

303

Effect of welding parameters on the heat-affected zone of AISI409 ferritic stainless steel  

NASA Astrophysics Data System (ADS)

One of the main problems during the welding of ferritic stainless steels is severe grain growth within the heat-affected zone (HAZ). In the present study, the microstructural characteristics of tungsten inert gas (TIG) welded AISI409 ferritic stainless steel were investigated by electron backscattered diffraction (EBSD), and the effects of welding parameters on the grain size, local misorientation, and low-angle grain boundaries were studied. A 3-D finite element model (FEM) was developed to predict the effects of welding parameters on the holding time of the HAZ above the critical temperature of grain growth. It is found that the base metal is not fully recrystallized. During the welding, complete recrystallization is followed by severe grain growth. A decrease in the number of low-angle grain boundaries is observed within the HAZ. FEM results show that the final state of residual strains is caused by competition between welding plastic strains and their release by recrystallization. Still, the decisive factor for grain growth is heat input.

Ranjbarnodeh, Eslam; Hanke, Stefanie; Weiss, Sabine; Fischer, Alfons

2012-10-01

304

Investigation of Low-Cycle Bending Fatigue of AISI 9310 Steel Spur Gears  

NASA Technical Reports Server (NTRS)

An investigation of the low-cycle bending fatigue of spur gears made from AISI 9310 gear steel was completed. Tests were conducted using the single-tooth bending method to achieve crack initiation and propagation. Tests were conducted on spur gears in a fatigue test machine using a dedicated gear test fixture. Test loads were applied at the highest point of single tooth contact. Gear bending stresses for a given testing load were calculated using a linear-elastic finite element model. Test data were accumulated from 1/4 cycle to several thousand cycles depending on the test stress level. The relationship of stress and cycles for crack initiation was found to be semilogarithmic. The relationship of stress and cycles for crack propagation was found to be linear. For the range of loads investigated, the crack propagation phase is related to the level of load being applied. Very high loads have comparable crack initiation and propagation times whereas lower loads can have a much smaller number of cycles for crack propagation cycles as compared to crack initiation.

Handschuh, Robert F.; Krantz, Timothy L.; Lerch, Bradley A.; Burke, Christopher S.

2007-01-01

305

Effect of shot peening on surface fatigue life of carburized and hardened AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Surface fatigue tests were conducted on two groups of AISI 9310 spur gears. Both groups were manufactured with standard ground tooth surfaces, with the second group subjected to an additional shot peening process on the gear tooth flanks. The gear pitch diameter was 8.89 cm (3.5 in.). Test conditions were a gear temperature of 350 K (170 F), a maximum Hertz stress of 1.71 billion N/sq m (248,000 psi), and a speed of 10,000 rpm. The shot peened gears exhibited pitting fatigue lives 1.6 times the life of standard gears without shot peening. Residual stress measurements and analysis indicate that the longer fatigue life is the result of the higher compressive stress produced by the shot peening. The life for the shot peened gear was calculated to be 1.5 times that for the plain gear by using the measured residual stress difference for the standard and shot peened gears. The measured residual stress for the shot peened gears was much higher than that for the standard gears.

Townsend, D. P.; Zaretsky, E. V.

1982-01-01

306

Effect of lubricant extreme-pressure additives on surface fatigue life of AISI 9310 spur gears  

NASA Technical Reports Server (NTRS)

Surface fatigue tests were conducted with AISI 9310 spur gears using a formulated synthetic tetraester oil (conforming to MIL-L-23699 specifications) as the lubricant containing either sulfur or phosphorus as the EP additive. Four groups of gears were tested. One group of gears tested without an additive in the lubricant acted as the reference oil. In the other three groups either a 0.1 wt % sulfur or phosphorus additive was added to the tetraester oil to enhance gear surface fatigue life. Test conditions included a gear temperature of 334 K (160 F), a maximum Hertz stress of 1.71 GPa (248 000 psi), and a speed of 10,000 rpm. The gears tested with a 0.1 wt % phosphorus additive showed pitting fatigue life 2.6 times the life of gears tested with the reference tetraester based oil. Although fatigue lives of two groups of gears tested with the sulfur additive in the oil showed improvement over the control group gear life, the results, unlike those obtained with the phosphorus oil, were not considered to be statistically significant.

Scibbe, H. W.; Townsend, D. P.; Aron, P. R.

1984-01-01

307

ALS Association  

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308

Nondestructive measurement of the residual stress TiN thin film coated on AISI 304 substrate by x-ray stress analyzer  

NASA Astrophysics Data System (ADS)

Titanium nitride films are deposited on AISI 304 steel with a hollow-cathode-discharge (HCD) ion-plating technique. The status of residual stresses in TiN thin film coated on AISI304 substrate by HCD is studied by x-ray diffraction stress analyzer. By analyzing morphology of the residual stress of TiN thin film at interface between TiN film and AISI 304 substrate, the adhering mechanism of TiN thin film is understood as follows: the mechanical interlocking had important contribution to the adhesion strength, the thermal stress is the major factor which resulting TiN thin film peeling off spontaneously. The results show that the value of thin film is -210MPa~-650Mpa, and the thermal stress is compressive, the intrinsic stress is tensile, origins of the residual stress are primarily discussed.

Zhang, Y. K.; Feng, A. X.; Lu, J. Z.; Kong, D. J.; Tang, C. P.

2006-01-01

309

Effect of martensite to austenite reversion on the formation of nano/submicron grained AISI 301 stainless steel  

SciTech Connect

The martensite to austenite reversion behavior of 90% cold rolled AISI 301 stainless steel was investigated in order to refine the grain size. Cold rolled specimens were annealed at 600-900 deg. C, and subsequently characterized by scanning electron microscopy, X-ray diffraction, Feritscope, and hardness measurements. The effects of annealing parameters on the formation of fully-austenitic nano/submicron grained structure and the mechanisms involved were studied. It was found that annealing at 800 deg. C for 10 s exhibited the smallest average austenite grain size of 240 {+-} 60 nm with an almost fully-austenitic structure.

Karimi, M.; Najafizadeh, A. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Kermanpur, A., E-mail: ahmad_k@cc.iut.ac.ir [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of); Eskandari, M. [Department of Materials Engineering, Isfahan University of Technology, Isfahan 84156-83111 (Iran, Islamic Republic of)

2009-11-15

310

Rutherford backscattering spectrometry (RBS) characterization of oxide scale formed on (AISI-304) steel after surface deposition of lanthanum  

SciTech Connect

Oxidized AISI-304 steel samples coated with lanthanum have been investigated by Rutherford backscattering spectrometry (RBS) in order to determine the composition profile of the oxide scale. In this sense, RBS technique has been revealed as a very reliable and nondestructive method for depth profile analysis. Lanthanum deposition, specially over preoxidized specimens, has proven to improve their resistance to high temperature oxidation. The formation of a LaCrO{sub 3} perovskite-like phase uniformly distributed along the oxide scale is proposed as being responsible for this behavior.

Ager, F.J.; Respaldiza, M.A.; Benitez, J.J.; Odriozola, J.A. [Univ. de Sevilla (Spain)] [Univ. de Sevilla (Spain); Botella, J. [Acerinox S.A., Los Barrios, Cadiz (Spain)] [Acerinox S.A., Los Barrios, Cadiz (Spain); Soares, J.C. [Univ. de Lisboa (Portugal). Centro de Fisica Nuclear] [Univ. de Lisboa (Portugal). Centro de Fisica Nuclear; Silva, M.F. da [Inst. Nacional de Engenheria e Tecnologia Industrial, Sacavem (Portugal)] [Inst. Nacional de Engenheria e Tecnologia Industrial, Sacavem (Portugal)

1996-02-01

311

Multi-component boron coatings on low carbon steel AISI 1018  

NASA Astrophysics Data System (ADS)

Boronizing and metalizing are thermo-chemical surface hardening treatments in which boron and metal atoms diffuse into the metal substrate forming metallic boride layers, providing complex properties of B-Me-Fe system. To study multi-component boron coatings on low carbon steel AISI 1018, the simultaneous powder pack method of boronizing and metalizing was selected to perform the coatings. One B-Fe system and eight boron-metal (B-Me-Fe) systems from transition metals group IVB (Ti, Zr, HO, group VB (Nb, Ta), and group VIB (Cr, Mo, W) were studied. The system specimens were thereto-chemically treated at 950°C for 4 hours in a crucible containing powder mixture of boron source, transition metal powder, and activator. After the heat treatment process, the multi-component boron coatings were characterized by using optical microscope, microhardness tester, TGA, XRD, and Synchrotron microdiffraction. The coating morphology was observed and the coating thickness was measured as well as the microhardness across the depth of coating. The corrosion resistance of the coatings was evaluated by the continuous weighting method. The high temperature oxidation was also detected by isothermal method at a temperature range of 400-800°C for 24 hours. The Rietveld refinement method was used to examine the quantitative phase analysis, crystalline size, microstrain and lattice parameters of the multi-component boron coatings. The results have shown that adding transition metals into the B-Fe system caused the formation of solid solution of transition-metal borides. The distortion of crystal lattice parameters generated microstrain in the boride phase. The Synchrotron microdiffraction confirmed the presence of about 5-10 microns of transition-metal boride phase at the surface. Moreover, the additional transition metal can provide better corrosion and high temperature oxidation resistance to the B-Fe system, preventing the deboronizing and stabilizing the boride phases.

Suwattananont, Naruemon

312

Fracture toughness of aisi M2 high-speed steel and corresponding matrix tool steel  

NASA Astrophysics Data System (ADS)

The influence of microstructural variations on the fracture toughness of two tool steels with compositions 6 pct W-5 pct Mo-4 pct Cr-2 pct V-0.8 pct C (AISI M2 high-speed steel) and 2 pct W-2.75 pct Mo-4.5 pct Cr-1 pct V-0.5 pct C (VASCO-MA) was investigated. In the as-hardened condition, the M2 steel has a higher fracture toughness than the MA steel, although the latter steel is softer. In the tempered condition, MA is softer and has a higher fracture toughness than M2. When the hardening temperature is below 1095 °C (2000 °F), tempering of both steels causes embrittlement, i.e., a reduction of fracture toughness as well as hardness. The fracture toughness of both steels was enhanced by increasing the grain size. The steel samples with intercept grain size of 5 (average grain diameter of 30 microns) or coarser exhibit 2 to 3 MPa?m (2 to 3 ksi?in.) higher fracture toughness than samples with intercept grain size of 10 (average grain diameter of 15 microns) or finer. Tempering temperature has no effect on the fracture toughness of M2 and MA steels as long as the final tempered hardness of the steels is constant. Retained austenite has no influence on the fracture toughness of as-hardened MA steel, but a high content of retained austenite appears to raise the fracture toughness of as-hardened M2 steel. There is a temperature of austenitization for each tool steel at which the retained austenite content in the as-quenched samples is a maximum. The above described results were explained through changes in the microstructure and the fracture modes.

Kim, Chongmin; Johnson, A. Richard; Hosford, William F.

1982-09-01

313

High temperature oxidation behavior of austenitic stainless steel AISI 304 in steam of nanofluids contain nanoparticle ZrO2  

NASA Astrophysics Data System (ADS)

The objective of this study is to evaluate high temperature oxidation behavior of austenitic stainless steel SS 304 in steam of nanofluids contain nanoparticle ZrO2. The oxidation was performed at high temperatures ranging from 600 to 800°C. The oxidation time was 60 minutes. After oxidation the surface of the samples was analyzed by different methods including, optical microscope, scanning electron microscope (SEM) and X-ray diffraction (XRD). X-ray diffraction examination show that the oxide scale formed during oxidation of stainless steel AISI 304 alloys is dominated by iron oxide, Fe2O3. Minor element such as Cr2O3 is also appeared in the diffraction pattern. Characterization by optical microscope showed that cross section microstructure of stainless steel changed after oxidized with the oxide scale on the surface stainless steels. SEM and x-ray diffraction examination show that the oxide of ZrO2 appeared on the surface of stainless steel. Kinetic rate of oxidation of austenite stainless steel AISI 304 showed that increasing oxidation temperature and time will increase oxidation rate.

Prajitno, Djoko Hadi; Syarif, Dani Gustaman

2014-03-01

314

Influence of Surface Preparation on the Kinetics of Controlled Gas-Nitrided AISI H13 Steels Used in Extrusion Dies  

NASA Astrophysics Data System (ADS)

In the aluminum extrusion practice, gas nitriding represents an important factor in enhancing the service life of AISI H13 steel dies. It is observed that if the die-bearing surface is not adequately prepared before nitriding, a nonuniform and shallow nitrided layer develops with reduced hardening effect. The focus of this paper is to investigate the influence of different surface conditions in terms of roughness on the kinetics of nitrided layer developed during gas-nitriding process under controlled nitriding potential. Four samples made of AISI H13 steel properly heat treated (quenched and tempered) were considered: without surface preparation, ground, polished, and lapped. All the samples were gas nitrided under the same conditions and examined after being nitrided. The nitrided layers were characterized using different techniques including optical microscopy, scanning electron microscopy, x-ray diffraction analysis, energy dispersive spectrometry mapping, and microhardness analysis. It was found that the surface preparation prior to nitriding significantly enhanced the nitriding kinetics, which in turn resulted in even and deep nitrided case depth. This provided high load-bearing capacity due to increased and deep hardening effect as compared to unprepared sample. A thinner and uniform compound layer with well-resolved phases was achieved in comparison with unprepared sample.

Akhtar, S. S.; Arif, A. F. M.; Yilbas, B. S.; Sheikh, A. K.

2010-04-01

315

Effects of electroplated zinc-nickel alloy coatings on the fatigue strength of AISI 4340 high-strength steel  

NASA Astrophysics Data System (ADS)

Recovered substrates have been extensively used in the aerospace field. Cadmium electroplating has been widely applied to promote protective coatings in aeronautical components, resulting in excellent corrosion protection combined with a good performance in cyclic loading. Ecological considerations allied to the increasing demands for corrosion resistance have resulted in the search for possible alternatives. Zinc-nickel (Zn-Ni) alloys have received considerable interest recently, because these coatings show advantages such as a good resistance to white and red rust, high plating rates, and acceptance in the market. In this study, the effect of electroplated Zn-Ni coatings on AISI 4340 high-strength steel was analyzed for rotating bending fatigue strength, corrosion, and adhesion resistance. The compressive residual stress field was measured by x-ray diffraction prior to fatigue tests. Optical microscopy documented coating thickness, adhesion characteristics, and coverage extent for nearly all substrates. Fractured fatigue specimens were investigated using scanning electron microscopy (SEM). Three different Zn-Ni coating thicknesses were tested, and comparisons with the rotating bending fatigue data from electroplated Cd specimens were performed. Experimental results differentiated the effects of the various coatings on the AISI 4340 steel behavior when submitted to fatigue testing and the influence of coating thickness on the fatigue strength.

Voorwald, H. J. C.; Miguel, I. M.; Peres, M. P.; Cioffi, M. O. H.

2005-04-01

316

Predictive modeling and experimental results for residual stresses in laser hardening of AISI 4140 steel by a high power diode laser  

Microsoft Academic Search

A predictive model for residual stresses induced in a laser hardened workpiece of AISI 4140 steel with no melting has been developed and experimentally verified. A transient three-dimensional thermal and kinetic model is first solved to obtain the temperature and solid phase history of the workpiece, which is then sequentially coupled to a three-dimensional stress model to predict residual stresses.

Neil S. Bailey; Wenda Tan; Yung C. Shin

2009-01-01

317

Predictive modeling and experimental results for laser hardening of AISI 1536 steel with complex geometric features by a high power diode laser  

Microsoft Academic Search

This paper presents predictive modeling and experimental results on laser hardening of AISI 1536 steel shafts with a complex geometric feature. A three-dimensional thermal model is used to predict the workpiece temperature distribution, which is coupled to a two-dimensional kinetic model to predict the resultant hardness and phase distribution. Surface temperature measurements are performed to validate the thermal model, while

Stephen Skvarenina; Yung C. Shin

2006-01-01

318

Effect of the micro-plasma arc welding technique on the microstructure and pitting corrosion of AISI 316L stainless steels in heavy LiBr brines  

Microsoft Academic Search

The effects of the micro-plasma arc welding technique on the microstructure and pitting corrosion of different zones of an AISI 316L stainless steel were studied using different microscopy and electrochemical techniques. Galvanodynamic measurements and laser scanning confocal microscope were used to evaluate the corrosion evolution in situ. Results show, in general, the worst corrosion behaviour for the heat affected zone.

R. Sánchez-Tovar; M. T. Montañés; J. García-Antón

2011-01-01

319

The effect of chamfer angle of polycrystalline cubic boron nitride cutting tool on the cutting forces and the tool stresses in finishing hard turning of AISI 52100 steel  

Microsoft Academic Search

Cutting experiments and finite element analysis (FEA) using ANSYS software have been carried out in this paper in order to investigate the effects of chamfer angle on the cutting forces and the cutting tool stresses, principal and von Mises stress, of polycrystalline cubic boron nitride (PCBN) cutting tools in finishing hard turning of AISI 52100 bearing steel. The obtained cutting

Abdullah Kurt; Ulvi ?eker

2005-01-01

320

Effect of the lubrication-cooling technique, insert technology and machine bed material on the workpart surface finish and tool wear in finish turning of AISI 420B  

Microsoft Academic Search

The paper is focussed on the effects produced by cutting operations on workpiece surface finish and tool wear. To this end, finish turning of AISI 420B stainless-steel was carried out under wet, minimum quantity of lubricant and dry cutting conditions, using both conventional and wiper technology inserts, on turning centres equipped with beds made in polymer concrete and cast iron.

C. Bruni; A. Forcellese; F. Gabrielli; M. Simoncini

2006-01-01

321

Selection of Optimum Drilling Parameters on Burr Height Using Response Surface Methodology and Genetic Algorithm in Drilling of AISI 304 Stainless Steel  

Microsoft Academic Search

This article illustrates an application of response surface methodology (RSM) and genetic algorithm (GA) for selecting the optimum combination values of drilling parameters affecting the burr height in drilling of AISI 304 stainless steel. The purpose of this article is to investigate the influence of the cutting parameters, such as cutting speed and feed rate, and point angle on burr

Erol Kilickap; Mesut Huseyinoglu

2010-01-01

322

Study of surface roughness and hardness of low carbon nickel-chromium based alloy steels under high temperature (AISI sae8630, 3140 & 9310)  

Microsoft Academic Search

High temperature Tribology is an interesting and challenging area which deserves more attention on wear resistance. The present investigation relates to understanding the surface roughness and hardness by the effect of different operational conditions like wear pressure, sliding speed and ambient temperature on AISI SAE 8630, 3140, and 9310. Dry sliding wear tests have been carried out on the materials

S. M. Ganechari; V. R. Kabadi; S. A. Kori

2011-01-01

323

Results of Corrosion Testing of Electroslag-Remelted Cr Ni Stainless Steel AISI 304 L (Material No. 1.4306) in Nitric Acid.  

National Technical Information Service (NTIS)

Under the aspect of application in reprocessing plants for nuclear fuel the ELC-quality of the Cr Ni stainless steel AISI 304, additionally purified by the electroslag-remelting-process, was tested as forged and rolled (sheet) material in nitric acid of d...

R. Kraft S. Leistikow E. Pott

1985-01-01

324

Ion implantation boriding of iron and AISI M2 steel using a high-current density, low energy, broad-beam ion source  

Microsoft Academic Search

Ions derived from solid boron and extracted into a broad beam were implanted at low energies into ?-iron and AISI M2 tool steel surfaces to alter their tribological characteristics. The implantations were accomplished at elevated temperatures and this facilitated thermal diffusion yielding relatively thick treated layers. The effects of the surface temperature associated with the implantation process on sliding wear

J. A. Davis; P. J. Wilbur; D. L. Williamson; R. Wei; J. J. Vajo

1998-01-01

325

Al Composites  

NASA Astrophysics Data System (ADS)

In the present study, cold spraying technique was used to fabricate a metal matrix composite (MMC) that consists of Ni matrix and 20 vol.% Ni3Al particles at two different particle sizes as reinforcement. This study intends to investigate the effect of reinforcement particle size on microstructural and mechanical properties of cold sprayed MMCs. Two different Ni3Al powders with nominal particle size of -45 to +5 and +45 to 100 ?m were used as reinforcement in this study. Cold sprayed Ni-Ni3Al samples were subjected to the microstructural observation and characterization prior to any mechanical testing. Then, samples were tested using nano-indentation, Knoop hardness, Vickers hardness, and Resonance frequency to evaluate their mechanical properties. No significant changes were observed in microstructural characteristics due to different particle sizes. The results obtained from a variety of mechanical testings indicated that the increasing reinforcement particle size resulted in the slight reduction of mechanical properties such as elastic modulus and hardness in cold sprayed MMCs. The mechanical interlock between deposited particles defines the bonding strength in cold sprayed samples. Small size particles have a higher velocity and impact resulting in stronger interlock between deformed particles.

Chandanayaka, Tharaka; Azarmi, Fardad

2014-05-01

326

Effects of AISI 316L corrosion products in in vitro bone formation.  

PubMed

Rat bone marrow cells were cultured in experimental conditions that favour the proliferation and differentiation of osteoblastic cells (i.e., 2.52 x 10(-4) mol l(-1) ascorbic acid, 10(-2) mol l(-1) beta-glycerophosphate and 10(-8) mol l(-1) dexamethasone) in the absence and in the presence of stainless-steel corrosion products, for a period of 18 days. An AISI 316L stainless-steel slurry (SS) was obtained by electrochemical means and the concentrations of the major metal ions, determined by atomic absorption spectrometry, were 8.78 x 10(-3) mol l(-1) of Fe, 4.31 x 10(-3) mol l(-1) of Cr and 2.56 x 10(-3) mol l(-1) of Ni. Bone marrow cells were exposed to 0.01, 0.1 and 1% of the SS and at the end of the incubation period, control and treated cultures were evaluated by histochemical assays for the identification of the presence of alkaline phosphatase and also calcium and phosphate deposition. Cultures were further observed by scanning electron microscopy. Levels of total and ionised calcium and phosphorus in the culture media collected from control and metal exposed cell cultures were also quantified. Histochemical staining showed that control cultures presented a strong reaction for the presence of alkaline phosphatase and exhibited formation of calcium and phosphates deposits. The presence of 0.01% SS caused no detectable biological effects in these cultures, 0.1% SS impaired osteoblastic behaviour and, 1% SS resulted in cell death. In the absence of bone cells, levels of total and ionised calcium and phosphorus in the control and metal added culture medium were similar throughout the incubation period. A significant decrease in the levels of ionised calcium and phosphorus were observed in the culture medium of control cultures and also in cultures exposed to 0.01% SS after two weeks of incubation, an event related with the formation of mineral calcium phosphate deposits in these cultures. In cultures grown in the presence of 0.1 and 1% SS corrosion products, levels of calcium and phosphorus were similar to those observed in the absence of cells. Results showed that stainless-steel corrosion products above certain concentrations may disturb the normal behaviour of osteoblast-like rat bone marrow cell cultures. PMID:9692798

Morais, S; Sousa, J P; Fernandes, M H; Carvalho, G S; de Bruijn, J D; van Blitterswijk, C A

1998-06-01

327

AL Amyloidosis  

PubMed Central

Definition of the disease AL amyloidosis results from extra-cellular deposition of fibril-forming monoclonal immunoglobulin (Ig) light chains (LC) (most commonly of lambda isotype) usually secreted by a small plasma cell clone. Most patients have evidence of isolated monoclonal gammopathy or smoldering myeloma, and the occurrence of AL amyloidosis in patients with symptomatic multiple myeloma or other B-cell lymphoproliferative disorders is unusual. The key event in the development of AL amyloidosis is the change in the secondary or tertiary structure of an abnormal monoclonal LC, which results in instable conformation. This conformational change is responsible for abnormal folding of the LC, rich in ? leaves, which assemble into monomers that stack together to form amyloid fibrils. Epidemiology AL amyloidosis is the most common type of systemic amyloidois in developed countries with an estimated incidence of 9 cases/million inhabitant/year. The average age of diagnosed patients is 65 years and less than 10% of patients are under 50. Clinical description The clinical presentation is protean, because of the wide number of tissues or organs that may be affected. The most common presenting symptoms are asthenia and dyspnoea, which are poorly specific and may account for delayed diagnosis. Renal manifestations are the most frequent, affecting two thirds of patients at presentation. They are characterized by heavy proteinuria, with nephrotic syndrome and impaired renal function in half of the patients. Heart involvement, which is present at diagnosis in more than 50% of patients, leading to restrictive cardiopathy, is the most serious complication and engages prognosis. Diagnostic methods The diagnosis relies on pathological examination of an involved site showing Congo red-positive amyloid deposits, with typical apple-green birefringence under polarized light, that stain positive with an anti-LC antibody by immunohistochemistry and/or immunofluorescence. Due to the systemic nature of the disease, non-invasive biopsies such as abdominal fat aspiration should be considered before taking biopsies from involved organs, in order to reduce the risk of bleeding complications. Differential diagnosis Systemic AL amyloidosis should be distinguished from other diseases related to deposition of monoclonal LC, and from other forms of systemic amyloidosis. When pathological studies have failed to identify the nature of amyloid deposits, genetic studies should be performed to diagnose hereditary amyloidosis. Management Treatment of AL amyloidosis is based on chemotherapy, aimed at controlling the underlying plasma clone that produces amyloidogenic LC. The hematological response should be carefully checked by serial measurements of serum free LC. The association of an alkylating agent with high-dose dexamethasone has proven to be effective in two thirds of patients and is considered as the current reference treatment. New agents used in the treatment of multiple myeloma are under investigation and appear to increase hematological response rates. Symptomatic measures and supportive care is necessary in patients with organ failure. Noticeably, usual treatments for cardiac failure (i.e. calcium inhibitors, ?-blockers, angiotensin converting enzyme inhibitors) are inefficient or even dangerous in patients with amyloid heart disease, that should be managed using diuretics. Amiodarone and pace maker implantation should be considered in patients with rhythm or conduction abnormalities. In selected cases, heart and kidney transplantation may be associated with prolonged patient and graft survival. Prognosis Survival in AL amyloidosis depends on the spectrum of organ involvement (amyloid heart disease being the main prognosis factor), the severity of individual organs involved and haematological response to treatment.

2012-01-01

328

Surface fatigue life of carburized and hardened M50NiL and AISI 9310 spur gears and rolling-contact test bars  

NASA Technical Reports Server (NTRS)

Spur gear endurance tests and rolling-element surface tests were conducted to investigate vacuum-induction-melted, vacuum-arc-melted (VIM-VAR) M50NiL steel for use as a gear steel in advanced aircraft applications, to determine its endurance characteristics, and to compare the results with those for standard VAR and VIM-VAR AISI 9310 gear material. Tests were conducted with spur gears and rolling-contact bars manufactured from VIM-VAR M50NiL and VAR and VIM-VAR AISI 9310. The gear pitch diameter was 8.9 cm (3.5 in.). Gear test conditions were an inlet oil temperature of 320 K (116 F), and outlet oil temperature of 350 K (170 F), a maximum Hertz stress of 1.71 GPa (248 ksi), and a speed of 10,000 rpm. Bench rolling-element fatigue tests were conducted at ambient temperatures with a bar speed of 12,500 rpm and a maximum Hertz stress of 4.83 GPA (700 ksi). The VIM-VAR M50NiL gears had a surface fatigue life that was 4.5 and 11.5 times that for VIM-VAR and VAR AISI 9310 gears, respectively. The surface fatigue life of the VIM-VAR M50NiL rolling-contact bars was 13.2 and 21.6 times that for the VIM-VAR and VAR AISI 9310, respectively. The VIM-VAR M50NiL material was shown to have good resistance to fracture through a fatigue spall and to have fatigue life far superior to that of both VIM-VAR and VAR AISI 9310 gears and rolling-contact bars.

Townsend, Dennis P.; Bamberger, Eric N.

1989-01-01

329

Ensayo de Corrosion de Mallas en Laminados de Fibra de Carbono Probetas de Impacto al Rayo (Corrosion Tests of Meshes in Carbon Fiber Laminates: Impact Beam Tests).  

National Technical Information Service (NTIS)

Corrosion resistance test results of copper alloy metal meshes, used in beam impact tests, are summarized. The use of a painting system is advised to avoid corrosion appearance in the metal meshes during an aircraft's service lifetime.

1990-01-01

330

HVEM studies of the effects of hydrogen on the deformation and fracture of AISI type 316 austenitic stainless steel  

SciTech Connect

The mechanisms of hydrogen embrittlement in AISI type 316 austenitic stainless steel have been investigated by in situ straining in a high-voltage electron microscope (HVEM) equipped with an environmental cell. Hydrogen effects on strain-induced phase transformations, the generation rate and velocity of dislocations, and crack propagation rates were studied. The salient features of the fracture were similar for cracks propagating in vacuum and in hydrogen gas. In each case, [epsilon] and [alpha][prime] martensite formed at the crack; the [epsilon] phase extended ahead of the crack while the [alpha][prime] phase was restricted to high stress regions near the crack tip. The principal effect of hydrogen was to decrease the stress required for dislocation motion, for phase transformation of the austenite, and for crack propagation.

Rozenak, P.; Robertson, I.M.; Birnbaum, H.K. (Univ. of Illinois, Urbana (United States))

1990-01-01

331

Mechanical behavior of AISI 304SS determined by miniature test methods after neutron irradiation to 28 dpa  

NASA Astrophysics Data System (ADS)

The mechanical properties of AISI 304 stainless steel irradiated for over a decade in the Experimental Breeder Reactor (EBR-II) were measured using miniature mechanical testing methods. The shear punch method was used to evaluate the shear strengths of the neutron-irradiated steel and a correlation factor was empirically determined to predict its tensile strength. The strength of the stainless steel slightly decreased with increasing irradiation temperature, and significantly increased with increasing dose until it saturated above approximately 5 dpa. An effective tensile strain hardening exponent was also obtained from the data which shows a relative decrease in ductility of steel with increased irradiation damage. Ferromagnetic measurements were used to observe and deduce the effects of the stress-induced austenite to martensite transformation as a result of shear punch testing.

Rabenberg, Ellen M.; Jaques, Brian J.; Sencer, Bulent H.; Garner, Frank A.; Freyer, Paula D.; Okita, Taira; Butt, Darryl P.

2014-05-01

332

Methodology for optimizing the electropolishing of stainless steel AISI 316L combining criteria of surface finish and dimensional precision  

NASA Astrophysics Data System (ADS)

This work examines a methodology for optimizing electrochemical polishing conditions bearing in mind the criteria that enhance minimum surface roughness and dimensional precision (minimum loss of thickness). The study consisted in electrochemically polishing stainless steel AISI 316L (ISO 4954 X2CrNiMo17133E) under a combination of different temperatures (T) baths and current densities (J), and application times (t). The surface finish (?Ra) and dimensional variations (?h) of the electrochemically polished workpieces were assessed, and the experimental data of the variables was correlated as can be seen by the response surfaces. This methodology enables optimum working areas to be specified using the sole criteria of surface finish, or by using a combination of both criteria (minimum roughness and maximum precision). The methodology has proven to be an optimum method for selecting electrochemical polishing conditions using the combined criteria of surface finish and dimensional precision in accordance with design requirements.

Núñez, P. J.; García-Plaza, E.; Martín, A. R.; Trujillo, R.; de La Cruz, C.

2009-11-01

333

Quantifying Cutting and Wearing Behaviors of TiN- and CrN-Coated AISI 1070 Steel  

PubMed Central

Hard coatings such as titanium nitride (TiN) and chromium nitride (CrN) are widely used in cutting and forming tools against wear and corrosion. In the present study, hard coating films were deposited onto AISI 1070 steels by a cathodic arc evaporation plating (CAVP) technique. These samples were subjected to wear in a conventional lathe for investigating the tribological behaviour of coating structure, and prenitrided subsurface composition was characterized using scanning electron microscopy (SEM), line scan analyses and X-ray diffraction (XRD). The wear properties of TiN- and CrN-coated samples were determined using an on-line monitoring system. The results show that TiN-coated samples demonstrate higher wear resistance than CrN-coated samples.

Cakan, Ahmet; Ozkaner, Vedat; Yildirim, Mustafa M.

2008-01-01

334

Application of strainrange partitioning to the prediction of creep-fatigue lives of AISI types 304 and 316 stainless steel  

NASA Technical Reports Server (NTRS)

As a demonstration of the predictive capabilities of the method of Strainrange Partitioning, published high-temperature, low cycle, creep-fatigue test results on AISI Types 304 and 316 stainless steel were analyzed and calculated, cyclic lives compared with observed lives. Predicted lives agreed with observed lives within factors of two for 76 percent, factors of three for 93 percent, and factors of four for 98 percent of the laboratory tests analyzed. Agreement between observed and predicted lives is judged satisfactory considering that the data are associated with a number of variables (two alloys, several heats and heat treatments, a range of temperatures, different testing techniques, etc.) that are not directly accounted for in the calculations.

Saltsman, J. F.; Halford, G. R.

1976-01-01

335

Comparison of Austenite Decomposition Models During Finite Element Simulation of Water Quenching and Air Cooling of AISI 4140 Steel  

NASA Astrophysics Data System (ADS)

An indigenous, non-linear, and coupled finite element (FE) program has been developed to predict the temperature field and phase evolution during heat treatment of steels. The diffusional transformations during continuous cooling of steels were modeled using Johnson-Mehl-Avrami-Komogorov equation, and the non-diffusion transformation was modeled using Koistinen-Marburger equation. Cylindrical quench probes made of AISI 4140 steel of 20-mm diameter and 50-mm long were heated to 1123 K (850 °C), quenched in water, and cooled in air. The temperature history during continuous cooling was recorded at the selected interior locations of the quench probes. The probes were then sectioned at the mid plane and resultant microstructures were observed. The process of water quenching and air cooling of AISI 4140 steel probes was simulated with the heat flux boundary condition in the FE program. The heat flux for air cooling process was calculated through the inverse heat conduction method using the cooling curve measured during air cooling of a stainless steel 304L probe as an input. The heat flux for the water quenching process was calculated from a surface heat flux model proposed for quenching simulations. The isothermal transformation start and finish times of different phases were taken from the published TTT data and were also calculated using Kirkaldy model and Li model and used in the FE program. The simulated cooling curves and phases using the published TTT data had a good agreement with the experimentally measured values. The computation results revealed that the use of published TTT data was more reliable in predicting the phase transformation during heat treatment of low alloy steels than the use of the Kirkaldy or Li model.

Babu, K.; Prasanna Kumar, T. S.

2014-04-01

336

Hydrogen Uptake Enhancement and Accelerated Hydrogen Re-embrittlement of Cd-plated AISI 4340 Steel Bolts Coupled with IN718 Nuts  

NASA Astrophysics Data System (ADS)

Hydrogen re-embrittlement on anodically coated high strength steels could be of great concern because the uptake of hydrogen from the corrosion process can cause component failure. A scratched Cd-coated AISI 4340 steel membrane has been coupled with different materials reproducing crevice conditions, and the hydrogen uptake has been measured using a modified Devanathan-Stachurski permeation apparatus. Experimental tests proved that, in presence of a crevice, metals nobler than cadmium strongly enhance local hydrogen reduction on exposed steel areas, thus possibly favoring brittle failure of high strength steel components during service. Therefore, the coupling of uncoated nuts made of noble passive alloys (like Inconel) to Cd-plated AISI 4340 steel bolts should be avoided.

Lovicu, Gian Franco; Colombo, Costanza; de Sanctis, Massimo; Valentini, Renzo

2011-12-01

337

Performance of P10 TiN coated carbide tools when end milling AISI H13 tool steel at high cutting speed  

Microsoft Academic Search

A study was undertaken to investigate the performance of P10 TiN coated carbide inserts in semi-finishing and finishing end milling of hardened AISI H13 tool steel (50±3 HRC) at high cutting speed regime. The effects of cutting speed, feed rate, and depth of cut on the tool life were studied experimentally. For the tested range of milling conditions, the result

J. A. Ghani; I. A. Choudhury; H. H. Masjuki

2004-01-01

338

Mechanical properties of TiN x \\/Cr 1? x N thin films on plasma nitriding-assisted AISI H13 steel  

Microsoft Academic Search

In this paper, the effects of duplex treatment consisting of plasma nitriding and PVD hard coating on the surface properties of hot working tool steel were investigated. Three different coatings (TiN, CrN single layer coating and TiN\\/CrN multi-layer coating) were deposited on pre-plasma nitrided AISI H13 steel using unbalanced magnetron sputtering method and their oxidation and mechanical properties such as

SangYul Lee

2005-01-01

339

The initiation and propagation of stress corrosion cracking in AISI 4340 and 3.5 Ni?Cr?Mo?V rotor steel in constant load tests  

Microsoft Academic Search

Constant load tests with smooth tensile specimens of AISI 4340 and 3.5 Ni?Cr?Mo?V rotor steel were carried out to investigate the influence of prior creep on the initiation of stress corrosion cracking (SCC). SCC did initiate without any significant pitting corrosion or general corrosion. A period of prior creep in a non-SCC environment resulted in significantly reduced localised corrosion along

A. Oehlert; A. Atrens

1996-01-01

340

Evaluation of boron mobility on the phases FeB, Fe 2B and diffusion zone in AISI 1045 and M2 steels  

Microsoft Academic Search

The present study evaluates the growth kinetics of boride layers at the material surface on AISI 1045 and M2 steels during the paste boriding process. This surface hardening technique produces on the material two characteristic phases FeB, Fe2B and a transition zone, denominated diffusion zone, in the layer\\/substrate interface. The thermochemical treatment was done at three different temperatures: 1193, 1223

I. Campos; G. Ramírez; U. Figueroa; J. Martínez; O. Morales

2007-01-01

341

Formation and kinetics of FeB\\/Fe 2B layers and diffusion zone at the surface of AISI 316 borided steels  

Microsoft Academic Search

The kinetics of the FeB\\/Fe2B layers and diffusion zone at the surface of AISI 316 steels exposed to the powder-pack boriding process were studied in this work. FeB\\/Fe2B layers and diffusion zone measurements were taken at different temperatures and exposure times to validate diffusion-controlled growth during the boriding process. In order to obtain the boron diffusion coefficients at the FeB\\/Fe2B

I. Campos-Silva; M. Ortiz-Domínguez; O. Bravo-Bárcenas; M. A. Doñu-Ruiz; D. Bravo-Bárcenas; C. Tapia-Quintero; M. Y. Jiménez-Reyes

2010-01-01

342

CHARACTERIZATION OF FRICTION COEFFICIENT AND HEAT PARTITION COEFFICIENT BETWEEN AN AUSTENITIC STEEL AISI304L AND A TiN-COATED CARBIDE CUTTING TOOL  

Microsoft Academic Search

This work aims at characterizing the tribological behavior of an AISI304L austenitic steel and a TiN-coated carbide tool under extreme conditions corresponding to the one occurring at the cutting tool-work material in dry machining. A specially designed open tribometer has been used to characterize the friction coefficient, heat partition coefficient and adhesion in the contact versus sliding velocity and contact

J. Iraola; J. Rech; F. Valiorgue; P. J. Arrazola

2012-01-01

343

Influences of Cr\\/Ni equivalent ratios of filler wires on pitting corrosion and ductility-dip cracking of AISI 316L weld metals  

Microsoft Academic Search

To study the pitting corrosion of AISI 316L weld metals according to the chromium\\/nickel equivalent ratio (Creq\\/Nieq ratio), three filler wires were newly designed for the flux-cored arc welding process. The weld metal with delta-ferrite\\u000a at less than 3 vol.%, was observed for ductility-dip cracking (DDC) in the reheated region after multi-pass welding. The tensile\\u000a strength and yield strength increased

Y. H. Kim; D. G. Kim; J. H. Sung; I. S. Kim; D. E. Ko; N. H. Kang; H. U. Hong; J. H. Park; H. W. Lee

2011-01-01

344

Further considerations on the inconsistency in toughness evaluation of AISI 4340 steel austenitized at increasing temperatures. [Stainless steel 4340 and 300-M  

Microsoft Academic Search

A study was made of the influence of austenitizing temperature on the ambient temperature toughness of commercial AISI 4340 ultrahigh strength steel in the as-quenched (untempered) and quenched and tempered at 200°C conditions. A systematic trend of increasing plane strain fracture toughness (K\\/sub Ic\\/) and decreasing Charpy V-notch energy was observed as the austenitizing temperature was raised while the yield

R. O. Ritchie; R. M. Horn

1978-01-01

345

Stress corrosion cracking and anodic behavior of AISI 304 stainless steel, Inconel 600, and Incoloy 800 straining in boiling NaOH solutions  

Microsoft Academic Search

The straining electrode technique was used to evaluate the stress corrosion cracking (SCC) susceptibility of AISI 304 stainless steel in 20N NaOH solution, and of Inconel 600 Alloy and Incoloy 800 Alloy in boiling 17.5N NaOH solution. The crack propagation rate estimated from the straining experiments correlated well with failure time measurements from previous constant load experiments. It was found

Y. S. Park; J. R. Galvele; A. K. Agrawal; R. W. Staehle

1978-01-01

346

Microstructure and electrochemical properties of the bonding zone of AISI 316L steel joined with a Fe-based amorphous foil  

Microsoft Academic Search

The effect of temperature and holding time on the microstructure and corrosion resistance of the junction zone of AISI 316L stainless steel (SS) bonded to itself with Fe75Cr8P10B7 filler alloy was investigated. The brazing alloy was prepared in the laboratory in the form of amorphous ribbons and its melting temperature was determined by differential thermal analysis (DTA) to be 1571K.

J. A. Verduzco; J. González-Sánchez; V. H. Verduzco; J. Solís; J. Lemus-Ruiz

2010-01-01

347

3-Hydroxybenzoic acid as AISI 316L stainless steel corrosion inhibitorin a H 2 SO 4 –HF–H 2 O 2 pickling solution  

Microsoft Academic Search

3-Hydroxybenzoic acid (3-HBA) was studied for possible use as a AISI 316L stainless steel (SS) corrosion inhibitor in an environmental-friendly aqueous pickling solution of 75 g l-1 sulphuric acid (H2SO4), 25 g l-1 hydrofluoric acid (HF) and 30 g l-1 hydrogen peroxide (H2O2). 3-HBA was tested in concentrations from 5 × 10-5 to 5 × 10-1M at 298 and 313

L. Narváez; E. Cano; D. M. Bastidas

2005-01-01

348

Prediction of scuffing failure based on competitive kinetics of oxide formation and removal: Application to lubricated sliding of AISI 52100 steel on steel  

Microsoft Academic Search

A method for predicting scuffing failure based on the competitive kinetics of oxide formation and removal has been developed and applied to the sliding of AISI 52100 steel on steel with poly-alpha-olefin as the lubricant. Oxide formation rates were determining using static oxidation tests on coupons of 52100 steel covered with poly-alpha-olefin at temperatures of 140 C to 250 C.

Eric C. Cutiongco; Yip-Wah Chung

1994-01-01

349

Pitting of AISI 304L stainless steel coated with nano structured sol–gel alumina coatings in chloride containing acidic environments  

Microsoft Academic Search

Sol–gel coatings were applied on AISI 304L stainless steel and their pitting resistance was evaluated in different concentrations of chloride ions in 0.01M H2SO4 solution. AFM and XRD analyses of the coated surface confirmed the presence of nano structured ?-alumina phase in the coating. Anodic polarisation indicated a considerable shift of pitting potential of the substrate in the noble direction

G. Ruhi; O. P. Modi; I. B. Singh

2009-01-01

350

Identification by photoelectrochemistry of oxide phases grown during the initial stages of thermal oxidation of AISI 441 ferritic stainless steel in air or in water vapour  

Microsoft Academic Search

Room temperature photoelectrochemistry was used to characterise oxide phases grown during the initial stages of oxidation of the ferritic stainless steel AISI441 at 650°C and 850°C in synthetic air or in water vapour. Grazing incidence X-ray diffraction and Raman spectroscopy were additionally used to discuss PEC results. Haematite Fe2O3 (?2.0eV), chromia Cr2O3 (3.0 and 3.5eV) and their mutual solid solution

A. Srisrual; S. Coindeau; A. Galerie; J.-P. Petit; Y. Wouters

2009-01-01

351

Oxidation of nano-multilayered AlTiSiN thin films between 600 and 1000 degrees C in air.  

PubMed

Multilayered AlTiSiN films with a composition of 32.0Al-12.4Ti-4.9Si-50.7N (at.%) were deposited on a steel substrate in a nitrogen atmosphere by cathodic arc plasma deposition. The films consisted of crystalline approximately 8 nm-thick AISiN nanolayers that originated from the Al-Si target and approximately 3 nm-thick TiN nanolayers that originated from the Ti target. Their oxidation characteristics were studied between 600 and 1000 degrees C for up to 20 h in air. They displayed good oxidation resistance due to the formation of a thin, dense Al2O3 surface scale below which an (Al2O3, TiO2, SiO2)-intermixed inner scale existed. They oxidized slower than TiN films because protective Al2O3-rich scales formed on the surface. However, they oxidized faster than CrN films because impure Al2O3 scale formed on the AlTiSiN film. Their oxidation progressed primarily by the outward diffusion of nitrogen and substrate elements, combined with the inward transport of oxygen that gradually reacted with Al, Ti, and Si in the film. PMID:22121757

Lee, Jae Chun; Kim, Sun Kyu; Nguyen, Thuan Dinh; Lee, Dong Bok

2011-07-01

352

A novel determination of thermodynamic activities of metals in an AISI 316 stainless steel by a metastable emf method  

NASA Astrophysics Data System (ADS)

An emf technique was adopted for the first time for direct determination of thermodynamic activities of all major metallic components, namely, Fe, Cr, Ni and Mn in a commercial grade AISI 316 stainless steel in the temperature range of approximately 800 to 1200 K. The viability of this method was initially established in the case of chromium activity measurements which could be compared with literature values. For this purpose galvanic cells with M/MF 2 and [M] 316ss/MF 2 (M = Fe, Cr, Ni or Mn) were used, employing single crystal CaF 2 as the electrolyte. In addition, Mo activitiy in this alloy was measured using the emf of the galvanic cell, Pt, Mo, MoO 2/7 YDT/MoO 2, [Mo] 316ss, Pt The activities determined by these galvanic cells could be represented as follows: log a Cr(±0.02) = -0.577 + 69.1/T , log a Ni(±0.02) = 0.589 - 800.31/T , log a Fe(±0.01) = 0.179 - 248.54/T , log a Mn(±0.01) = 0.742 - 2581.40/T , log a Mo(±0.05) = -4.548 + 3148.48/T . These activities were used to compute the threshold oxygen levels in Na(l)/AISI 316 stainless steel system for the formation of the corrosion products, viz., NaCrO 2, Na 4FeO 3, MnO and NaMnO 2. These data in conjunction with the carbon activity in this alloy reported in the literature, and initial composition of the M 23C 6, phase, could lead to the estimation of the Gibbs energy change for a typical reaction, 2.571Cr + 0.732Fe + 0.303Mo + 0.226Ni + C M 23/6C , as follows: ?G of,T(M 23/6C, s) (kJ) = -29.16 - 0.0522T (K) .

Azad, A. M.; Sreedharan, O. M.; Gnanamoorthy, J. B.

1987-01-01

353

Corrosion-Erosion Effect on TiN/TiAlN Multilayers  

NASA Astrophysics Data System (ADS)

The goal of this work is to study electrochemical behavior under corrosion-erosion conditions for [TiN/TiAlN] n multilayer coatings with bilayer number ( n) of 2, 6, 12, and 24 and/or bilayer period (?) of 1500, 500, 250, 150, and 125 nm deposited by a magnetron sputtering technique on Si (100) and AISI 1045 steel substrates. The Ti-N and Ti-Al-N structures for multilayer coatings were evaluated via x-ray diffraction analysis. Silica particles were used as the abrasive material in corrosion-erosion tests within the 0.5 M H2SO4 solution at impact angles of 30° and 90° over the surface. The electrochemical characterization was carried out using the polarization resistance technique (Tafel) to observe changes in corrosion rates as a function of the bilayer number ( n) or bilayer period (?) and impact angle. Corrosion rate values of 359 mpy of uncoated steel substrate and 103 mpy for substrate coated with n = 24 (? = 125 nm) under an impact angle of 30° were found. On the other hand, with an impact angle of 90° the corrosion rate exhibited 646 mpy on uncoated steel substrate and 210 mpy for substrate coated with n = 24 (? = 125 nm). This behavior was related to the curves of mass loss for both coated samples and the surface damage was analyzed via SEM images for the two different impact angles. These results indicate that TiN/TiAlN multilayer coatings deposited on AISI 1045 steel are a practical solution for applications in erosive-corrosive environments.

Caicedo, J. C.; Cabrera, G.; Aperador, W.; Escobar, C.; Amaya, C.

2012-09-01

354

Who Gets ALS?  

MedlinePLUS

... help create a world without ALS Join this nationwide movement by walking for those affected by ALS Home > About ALS Share Print Who Gets ALS? En español ALS is a disorder that affects the function of nerves and muscles. Based on U.S. population studies, a little over 5,600 people in the ...

355

Effects of strain and strain-induced ?'-martensite on passive films in AISI 304 austenitic stainless steel.  

PubMed

In this paper, the effects of strain and heat treatment on strain-induced ?'-martensite of AISI 304 stainless steel tubes were measured by X-ray diffraction. Moreover, the effects of strain and content of ?'-martensite on passivated property on the surface of the material in borate buffer solution were evaluated by electrochemical technique. The results showed that the volume fraction of ?'-martensite increased gradually with the increase of tensile strain for as-received and solid solution samples. However, ?'-martensite in as-received sample was more than that in the solid solution sample. The electrochemical impedance spectroscopy results showed that the solid solution treatment improved corrosion resistance of the steel, especially for samples with small strain. Moreover, acceptor densities were always higher than donor densities for as-received and solid solution samples. With the increase of strain, the increase tendency of acceptor density was more significant than that of donor density. We also found that the total density of the acceptor and donor almost increased linearly with the increase of ?'-martensite. The present results indicated that the increased acceptor density might lead to the decreased corrosion resistance of the steel. PMID:24268285

Lv, Jinlong; Luo, Hongyun

2014-01-01

356

The effect of ultrasonic nanocrystalline surface modification on the high-frequency fretting wear behavior of AISI304 steel.  

PubMed

The fact that one of fundamental characteristics of fretting is the very small sliding amplitude dictates the unique feature of wear mechanism. Ultrasonic Nanocrystalline Surface Modification (UNSM) technology was applied in order to investigate its effect on the high-frequency fretting wear behavior of AISI304 steel. Its influence on the fretting wear is also reported in this paper with these treated and untreated samples. UNSM delivers force onto the workpiece surface 20,000 times per second with 1,000 to 4,000 contact counts per square millimeter. UNSM creates homogenous nanocrystalline structures as well on the surface. UNSM process is expected to eliminate or significantly retard the formation of fretting wear. Nanocrystalline structure generation after UNSM has been reported to produce its unique structure and to offer a variety of beneficial properties compared to conventionally treated materials. A deformed layer of 220 microm exhibits high dislocation density, where top layer transformed to a nanostructure of the grain size in 23 nm and mechanical twins were observed. Deformation-induced martensite was observed to form at the intersections of mechanical twins, whose volume fraction has increased up to 38.4% and wear loss rate at 800,000 cycles has decreased by 40%. In this paper, experimental results are discussed to elucidate potential mechanism of high-frequency fretting wear. PMID:21446536

Cho, In-Shik; Lee, Chang-Soon; Amanov, Auezhan; Pyoun, Young-Shik; Park, In-Gyu

2011-01-01

357

Effect of Ball Burnishing Process on the Surface Quality and Microstructure Properties of AISI 1010 Steel Plates  

NASA Astrophysics Data System (ADS)

A newly developed ball burnishing tool was designed and tested for surface finishing of large flat surfaces in a shortest possible time. Optimization and analysis of the burnishing process were carried on AISI 1010 steel hot-rolled plates using the Taguchi technique and response surface methodology (RSM) to identify the effect of burnishing parameters (i.e., burnishing speed, burnishing force, and feed rate) on surface roughness, surface hardness, and microstructure of burnished surfaces. The optimal burnishing parameters were found after conducting the Taguchi's L25 matrix experiments and obtaining the response models for the surface roughness and the hardness. It was found that the burnishing force has the most influential effect on the surface roughness and hardness, followed by the burnishing speed, and least influence by the feed rate. In addition, microstructural examinations of the burnished surface indicate that burnishing force more than 400 N causes flaking of the burnished surfaces. The optimal burnishing parameters for the steel plates were a combination of a burnishing speed of 235 rpm, a burnishing force of 400 N, and a feed rate of 0.18 mm/rev. Using these parameters, the mean surface roughness has been improved from Ra = 2.48 to 1.75 ?m, while the hardness increases from 59 to 65.5 HRB.

Gharbi, F.; Sghaier, S.; Al-Fadhalah, K. J.; Benameur, T.

2011-08-01

358

Effect of CO 2 laser cutting process parameters on edge quality and operating cost of AISI316L  

NASA Astrophysics Data System (ADS)

Laser cutting is a popular manufacturing process utilized to cut various types of materials economically. The width of laser cut or kerf, quality of the cut edges and the operating cost are affected by laser power, cutting speed, assist gas pressure, nozzle diameter and focus point position as well as the work-piece material. In this paper CO 2 laser cutting of stainless steel of medical grade AISI316L has been investigated. Design of experiment (DOE) was implemented by applying Box-Behnken design to develop the experiment lay-out. The aim of this work is to relate the cutting edge quality parameters namely: upper kerf, lower kerf, the ratio between them, cut section roughness and operating cost to the process parameters mentioned above. Then, an overall optimization routine was applied to find out the optimal cutting setting that would enhance the quality or minimize the operating cost. Mathematical models were developed to determine the relationship between the process parameters and the edge quality features. Also, process parameters effects on the quality features have been defined. Finally, the optimal laser cutting conditions have been found at which the highest quality or minimum cost can be achieved.

Eltawahni, H. A.; Hagino, M.; Benyounis, K. Y.; Inoue, T.; Olabi, A. G.

2012-06-01

359

The effect of prior cold-work on the deformation behaviour of neutron irradiated AISI 304 austenitic stainless steel  

NASA Astrophysics Data System (ADS)

Cold-work is intentionally employed to increase the yield strength of austenitic stainless steels and also occurs during fabrication processes, but it has also been associated with greater incidence of stress corrosion cracking. This study examined the effect of up to 3.85 dpa neutron irradiation on the deformation behaviour and microstructures of 30% cold-worked AISI 304 material tensile tested at 300 °C. While the deformation behaviour of 0.07 dpa material was similar to non-irradiated material tested at the same temperature, its stress-strain curve was shifted upwards by about 200 MPa. Materials irradiated to over 2 dpa hardened some 400-500 MPa, but showed limited strain hardening capacity, exhibiting precipitous softening with further straining beyond the yield point. The observed behaviour is most likely a consequence of planar deformation products serving as strengtheners to the unirradiated bulk on the one hand, while promoting strain localization on the other, behaviour exacerbated by the subsequent neutron irradiation.

Karlsen, Wade; Van Dyck, Steven

2010-11-01

360

Determination of neutron exposure of AISI 304 stainless steel from a BWR top guide using retrospective dosimetry  

NASA Astrophysics Data System (ADS)

Retrospective dosimetry was used to determine the accumulated neutron exposure of AISI 304 stainless steel removed from the top guide of a boiling water reactor located at the Oyster Creek nuclear power station. The material was removed from areas adjacent to cracks that were observed after ˜20 years of operation. Using the plant operational history and a variety of measurements of various radioisotopes or non-radioactive transmutation products produced by irradiation, it was possible to determine the integrated neutron fluence experienced by the cracked region and to specify the accumulated displacement dose. Dose estimates on two separate specimens adjacent to the cracks were found to average 1.5 ± 0.2 dpa, possibly reflecting some uncertainty in measurement but more likely suggesting a small gradient in neutron flux-spectra within the section from which the various analysis specimens were cut. This report demonstrates that it is possible to examine defective components lying outside of the core region and where neutron flux-spectra are not well known, and to use the induced transmutation products to determine the neutron exposure with some confidence by using the examined specimen as its own dosimeter.

Greenwood, L. R.; Garner, F. A.; Oliver, B. M.; Bruemmer, S. M.

2007-03-01

361

A Local Damage Approach to Predict Crack Initiation in Type AISI 316L(N) Stainless Steel  

NASA Astrophysics Data System (ADS)

A local damage approach based on plastic strain equivalent to uniform strain and grain diameter of the material is proposed for prediction of crack initiation. Plane strain, plane stress, and 3D FEM simulations are carried out for compact tension (CT) geometry with blunt notch of different a/ W ratios under mode-I loading. Elastic-plastic fracture parameters have been estimated based on certain assumptions on blunting at notch tip and micromechanisms of events leading to onset of crack. The various crack initiation parameters evaluated based on proposed local damage approach and initial assumptions have been verified by conducting experiments on CT specimens and subsequent scanning electron microscopy study on fracture surface. The laboratory scale experimental results of AISI 316L(N) stainless steel material are in good agreement with FEM-predicted fracture parameters for notch type of stress raisers. The local damage approach and FEM procedure established in the present study would be easily extendable to the analysis of stress raisers in components for the prediction of crack initiation under elastic-plastic condition.

Krishnan, S. A.; Sasikala, G.; Moitra, A.; Albert, S. K.; Bhaduri, A. K.

2014-05-01

362

Nano-Borides and Silicide Dispersed Composite Coating on AISI 304 Stainless Steel by Laser-Assisted HVOF Spray Deposition  

NASA Astrophysics Data System (ADS)

The study concerned a detailed microstructural investigation of nano-borides (Cr2B and Ni3B) and nano-silicide (Ni2Si) dispersed ?-nickel composite coating on AISI 304 stainless steel by HVOF spray deposition of the NiCrBSi precursor powder and subsequent laser surface melting. A continuous wave diode laser with an applied power of 3 kW and scan speed of 20 mm/s in argon shroud was employed. The characterization of the surface in terms of microstructure, microtexture, phases, and composition were carried out and compared with the as-coated (high-velocity oxy-fuel sprayed) surface. Laser surface melting led to homogenization and refinement of microstructures with the formation of few nano-silicides of nickel along with nano-borides of nickel and chromium (Ni3B, Cr2B, and Cr2B3). A detailed microtexture analysis showed the presence of no specific texture in the as-sprayed and laser-melted surface of Cr2B and Ni3B phases. The average microhardness was improved to 750-900 VHN as compared to 250 VHN of the as-received substrate. Laser surface melting improved the microhardness further to as high as 1400 VHN due to refinement of microstructure and the presence of silicides.

Sharma, Prashant; Majumdar, Jyotsna Dutta

2014-03-01

363

Biocompatibility studies of low temperature nitrided and collagen-I coated AISI 316L austenitic stainless steel.  

PubMed

The biocompatibility of austenitic stainless steels can be improved by means of surface engineering techniques. In the present research it was investigated if low temperature nitrided AISI 316L austenitic stainless steel may be a suitable substrate for bioactive protein coating consisting of collagen-I. The biocompatibility of surface modified alloy was studied using as experimental model endothelial cells (human umbilical vein endothelial cells) in culture. Low temperature nitriding produces modified surface layers consisting mainly of S phase, the supersaturated interstitial solid solution of nitrogen in the austenite lattice, which allows to enhance surface microhardness and corrosion resistance in PBS solution. The nitriding treatment seems to promote the coating with collagen-I, without chemical coupling agents, in respect of the untreated alloy. For biocompatibility studies, proliferation, lactate dehydrogenase levels and secretion of two metalloproteinases (MMP-2 and MMP-9) were determined. Experimental results suggest that the collagen protection may be favourable for endothelial cell proliferation and for the control of MMP-2 release. PMID:23471501

Martinesi, M; Stio, M; Treves, C; Borgioli, F

2013-06-01

364

Surface oxidation phenomenon and mechanism of AISI 304 stainless steel induced by Nd:YAG pulsed laser  

NASA Astrophysics Data System (ADS)

Surface oxidation phenomenon of AISI 304 stainless steel induced by Nd:YAG pulsed laser in air was investigated using scanning electron spectroscopy (SEM), high resolution transmission electron microscope (HRTEM), X-ray diffraction (XRD) and X-ray photoelectron spectroscopy (XPS). The results showed that there were different morphologies and phase compositions in one laser spot from the center to the edge on stainless steel surface after pulsed laser oxidation. The morphologies were mainly nano-spheres and hexagons. It was proved using XRD that they were basically ?-Fe, Cr2O3, Fe2O3 and a small amount of MnO2. The elemental compositions in the edge region were rich in Cr and deficient in Fe, while it had an opposite distribution trend in the center of the laser spot. XPS measurement confirmed the formed oxides on the stainless steel surface, indicating that most of the elements were in oxidation states. Moreover, the oxidation behavior of the stainless steel in one laser spot was assessed using thermodynamics and kinetics of laser oxidation process. And the oxidation mechanism was also clearly revealed.

Cui, C. Y.; Cui, X. G.; Ren, X. D.; Qi, M. J.; Hu, J. D.; Wang, Y. M.

2014-06-01

365

Influence of low energy-high flux nitrogen implantation on the oxidation behavior of AISI 304L austenitic stainless steel  

NASA Astrophysics Data System (ADS)

Low energy-high flux (1.2 keV, 1 mA/cm2) nitriding of an austenitic AISI 304L stainless steel has been carried out by implanting a dose of 3.5×1019 ions cm-2 at 400 °C for 1 h. An important increase in surface hardness has been found to occur as a result of the formation of the so-called expanded austenite ?N phase. Transmission electron microscopy studies have also shown the existence of hexagonal Cr2N precipitates at the nitrided layer/matrix interfacial region. The oxidation behavior has been then studied in the temperature range between 400 and 550 °C for 24 h under synthetic air. It is shown that nitridation slightly modifies the oxidation kinetics as a result of the progressive transformation of the ?N phase towards CrN precipitation and ?-FeNi matrix formation. More chromium enriched scales are, anyhow, developed on the nitrided steel than in the untreated one. These results are discussed on the basis of the chromium diffusion in the nitrided layer and its preferential chemical bonding with nitrogen atoms.

Pedraza, F.; Grosseau-Poussard, J. L.; Abrasonis, G.; Rivière, J. P.; Dinhut, J. F.

2003-12-01

366

The corrosion protection of AISI(TM) 1010 steel by organic and inorganic zinc-rich primers  

NASA Technical Reports Server (NTRS)

The behavior of zinc-rich primer-coated AISI 1010 steel in 3.5-percent Na-Cl was investigated using electrochemical techniques. The alternating current (ac) method of electrochemical impedance spectroscopy (EIS), in the frequency range of 0.001 to 40,000 Hz, and the direct current (dc) method of polarization resistance (PR), were used to evaluate the characteristics of an organic, epoxy zinc-rich primer and an inorganic, ethyl silicate zinc-rich primer. A dc electromechanical galvanic corrosion test was also used to determine the corrosion current of each zinc-rich primer anode coupled to a 1010 steel cathode. Duration of the EIS/PR and galvanic testing was 21 days and 24 h, respectively. The galvanic test results demonstrated a very high current between the steel cathode and both zinc-rich primer anodes (38.8 and 135.2 microns A/sq cm for the organic and inorganic primers, respectively). The results of corrosion rate determinations demonstrated a much higher corrosion rate of the zinc in the inorganic primer than in the organic primer, due primarily to the higher porosity in the former. EIS equivalent circuit parameters confirmed this conclusion. Based on this investigation, the inorganic zinc-rich primer appears to provide superior galvanic protection and is recommended for additional study for application on solid rocket booster steel hardware.

Danford, M. D.; Mendrek, M. J.

1995-01-01

367

An electrochemical noise study of tribocorrosion processes of AISI 304 L in Cl- and SO_{4}^{2-} media  

NASA Astrophysics Data System (ADS)

Electrochemical noise measurements were performed to investigate the intrinsically stochastic character of the tribocorrosion process. Unidirectional sliding tests (pin-on-disc) were performed using AISI 304L stainless steel sliding against corundum. Experiments were carried out in Cl- and SO_{4}^{2-} containing media under open-circuit and potentiostatic polarization conditions. The power spectral density (PSD) of the current and potential signals showed a strong dependence on the sliding frequency but did not depend significantly on the normal load between 5 and 20 N. The fluctuations of the tangential and normal loads were also recorded, and a critical comparison between the PSD of the electrochemical response and the PSD of the mechanical solicitation (load) is proposed. At high frequencies (f > 0.1 Hz), the PSD of current or potential fluctuations have significantly different shapes than the PSD of load signals: the electrochemical signal PSD is governed by the dynamic balance between local depassivation and repassivation which only depends on the kinetics of the electrochemical phenomena. For lower frequencies, a plateau is observed for both the electrochemical PSD and the load PSD. The electrochemical signal is then governed by the continuous depassivation induced by sliding which appears as a low frequency component. These results suggest that the electrochemical noise technique investigated in the frequency domain might be a promising electrochemical tool for successfully unfolding tribocorrosion signatures for material parings in sliding-corrosion tests.

Berradja, A.; Déforge, D.; Nogueira, R. P.; Ponthiaux, P.; Wenger, F.; Celis, J.-P.

2006-08-01

368

Fracture prediction in hydraulic bulging of AISI 304 austenitic steel sheets based on a modified ductile fracture criterion  

NASA Astrophysics Data System (ADS)

The demand for weight reduction in modern vehicle construction has resulted in an increase in the application of hydroforming processes for the manufacture of automotive lightweight components. This trend led to the research of evaluation on formability of the sheet or tube hydroforming to be noted, particularly the prediction of fracture. In this study, a new proposed approach based on damage theory for fracture prediction considering the deformation history was introduced. And the modified ductile fracture criterion was applied to predict the failure for hydraulic bulging of AISI 304 austenitic steel sheets. The material parameters in terms of the function of strain rate in the failure criterion were determined from the equivalent fracture strains corresponding tensile tests under different stress conditions. Then, in the finite element simulation the effect of strain rates and their distribution as well during practical sheet metal forming process was considered. The hydraulic bulging tests were carried out to identify the fracture behavior predicted from FE analysis. A comparison between the prediction and experimental results showed that the proposed approach with a modified ductile fracture criteria can give better fracture predictions than traditional ways.

Xu, Y.; Song, H. W.; Zhang, S. H.; Cheng, M.

2011-08-01

369

High temperature oxidation of HFPD thermal-sprayed MCrAlY coatings in simulated gas turbine environments  

NASA Astrophysics Data System (ADS)

NiCrAlY and CoNiCrAlY powders were thermal-sprayed using the high frequency pulse detonation method (HFPD) onto AISI 310 austenitic stainless steel samples to obtain dense, adherent, high temperature oxidation resistant coatings. The oxidation behavior of both types of coatings in a 1000°C simulated gas turbine environment was experimentally determined. The porosity, hardness, coating thickness, and microstructure were not significantly modified by the high temperature oxidation cycles, but the internal oxidation increases significantly after a very low oxidation time. Surface phase composition was evaluated using x-ray diffraction (XRD) and scanning electron microscope (SEM) techniques, revealing the formation of a continuous and highly protective alumina layer. The oxidation kinetics of both coatings can be characterized by parabolic rate constants, which are very close to those for the formation of aluminum oxide on nickel or cobalt based alloys at similar conditions.

Belzunce, F. J.; Higuera, V.; Poveda, S.; Carriles, A.

2002-12-01

370

Thermal conductivity of PVD TiAlN films using pulsed photothermal reflectance technique  

NASA Astrophysics Data System (ADS)

In the present work, we have measured thermal-conductivity of industrial thin film TiAlN with a thickness of around 3 ?m. These films are used in machining industry for cutting tools in order to increase their service life. A series of TiAlN coating with a different Al/Ti atomic ratio were deposited on Fe-304 stainless steel (AISI304) substrate by a lateral rotating cathode arc process. The samples were then coated with a 0.8 ?m gold layer on top by magnetron sputtering. We present the thermal-conductivity measurement of these samples using pulsed photothermal reflectance (PPR) technique at room temperature. The thermal conductivity of the pure TiN coating is about 11.9 W/mK. A significant decrease in thermal conductivity was found with increasing Al/Ti atomic ratio. A minimum thermal conductivity of about 4.63 W/mK was obtained at the Al/Ti atomic ratio of around 0.72.

Ding, Xing-Zhao; Samani, M. K.; Chen, George

2010-11-01

371

AISI 303 OSTEN?T?K PASLANMAZ ÇEL?KLER?N ??LENMES?NDE KESME HIZI VE ?LERLEMEN?N KESME KUVVETLER? VE YÜZEY PÜRÜZLÜLÜ?Ü ÜZER?NDEK? ETK?LER? THE EFFECTS OF CUTTING SPEED AND FEED RATE ON CUTTING FORCES AND SURFACE ROUGHNESS IN MACHINING OF AISI 303 AUSTENITIC STAINLESS STEEL  

Microsoft Academic Search

c,* ?brahim Ç?FTÇ? d Abstract In this study, the effects of cutting speed and feed rate on cutting forces and surface roughness by AISI 303 austenitic stainless steel machining have been investigated. The tests were carried out at four different cutting speeds (120, 150, 180 and 210 m\\/min) and three different feed rates (0.20, 0.24 and 0.30 mm\\/rev) at a

Hasan Emrah YEYEN; Yakup TURGUT

372

Continuous cooling and low temperature sensitization of AISI Types 316 SS and 304 SS With different degrees of cold work  

NASA Astrophysics Data System (ADS)

This paper presents the results of investigations carried out to study the sensitization behaviour of AISI Types 316 SS and 304 SS with various degrees of cold work ranging from 0 to 25%. Initially Time-Temperature-Sensitization (TTS) diagrams were established using ASTM standard A262 Practice A and E tests. From these diagrams it was found that the rate of sensitization and overall susceptibility to intergranular corrosion increases up to 15% cold work and above that starts decreasing. Desensitization was observed to be faster for higher levels of cold work, especially in the higher sensitization temperature range. From the TTS diagrams, the critical linear cooling rate below which sensitization occurs was calculated. From these data, Continuous Cooling Sensitization (CCS) diagrams were established. The results show that as the degree of cold work increases up to 15%, time needed for sensitization decreases and hence faster cooling rates must be used in order to avoid sensitization. At temperatures sufficiently below the nose temperature of the TTS diagram, logt versus 1/ T plots follow a linear relationship where t is the time needed for the onset of sensitization at temperature T. From the slope, the apparent activation energy for sensitization was estimated. The validity of extrapolating these linear plots to lower temperatures (725 to 775 K) (which lie in the operating temperature regime of fast reactors) has been verified by experiment. The effect of heat treatment and microstructure on the Low Temperature Sensitization (LTS) behaviour was investigated. The results indicate that carbides of optimum size and distribution are the essential pre-requisites for LTS and cold work enhances susceptibility of stainless steels to LTS.

Parvathavarthini, N.; Dayal, R. K.; Seshadri, S. K.; Gnanamoorthy, J. B.

1989-11-01

373

Microstructural Characterization and Properties Evaluation of Ni-Based Hardfaced Coating on AISI 304 Stainless Steel by High Velocity Oxyfuel Coating Technique  

NASA Astrophysics Data System (ADS)

The present study concerns a detailed investigation of microstructural evolution of nickel based hardfaced coating on AISI 304 stainless steel by high velocity oxy-fuel (HVOF) deposition technique. The work has also been extended to study the effect of coating on microhardness, wear resistance and corrosion resistance of the surface. Deposition has been conducted on sand blasted AISI 304 stainless steel by HVOF spraying technique using nickel (Ni)-based alloy [Ni: 68.4 wt pct, chromium (Cr): 17 wt pct, boron (B): 3.9 wt pct, silicon (Si): 4.9 wt pct and iron (Fe): 5.8 wt pct] of particle size 45 to 60 ?m as precursor powder. Under the optimum process parameters, deposition leads to development of nano-borides (of chromium, Cr2B and nickel, Ni3B) dispersion in metastable and partly amorphous gamma nickel (?-Ni) matrix. The microhardness of the coating was significantly enhanced to 935 VHN as compared to 215 VHN of as-received substrate due to dispersion of nano-borides in grain refined and partly amorphous nickel matrix. Wear resistance property under fretting wear condition against WC indenter was improved in as-deposited layer (wear rate of 4.65 × 10-7 mm3/mm) as compared to as-received substrate (wear rate of 20.81 × 10-7 mm3/mm). The corrosion resistance property in a 3.56 wt pct NaCl solution was also improved.

Sharma, Prashant; Majumdar, Jyotsna Dutta

2013-01-01

374

Ion Beam Analysis, structure and corrosion studies of nc-TiN/a-Si3N4 nanocomposite coatings deposited by sputtering on AISI 316L  

NASA Astrophysics Data System (ADS)

In this work, nanocomposite coatings of nc-TiN/a-Si3N4, were deposited on AISI 316L stainless steel substrate by a DC and RF reactive magnetron co-sputtering technique using an A-N2 plasma. The structure of the coatings was characterized by means of XRD (X-ray Diffraction). The substrate and coating corrosion resistance were evaluated by potentiodynamic polarization using a Ringer solution as electrolyte. Corrosion tests were conducted with the purpose to evaluate the potential of this coating to be used on biomedical alloys. IBA (Ion Beam Analysis) techniques were applied to measure the elemental composition profiles of the films and, XPS (X-ray Photoelectron Spectroscopy) were used as a complementary technique to obtain information about the compounds present in the films. The nanocomposite coatings of nc-TiN/a-Si3N4 show crystalline (TiN) and amorphous (Si3N4) phases which confer a better protection against the corrosion effects compared with that of the AISI 316L.

García, J.; Canto, C. E.; Flores, M.; Andrade, E.; Rodríguez, E.; Jiménez, O.; Solis, C.; de Lucio, O. G.; Rocha, M. F.

2014-07-01

375

/Cu-Al System  

NASA Astrophysics Data System (ADS)

Wettability and interfacial interaction of the Ta2O5/Cu-Al system were studied. Pure Cu does not wet the Ta2O5 substrate, and improved spreading is achieved when relatively a high fraction of the active element (~40 at.% Al) was added. The Al2O3 and AlTaO4 phases were observed at the Ta2O5/Cu-Al interface. A thermodynamic evaluation allowed us to suggest that the lack of wetting bellow 40 at.% Al is due to the presence of a native oxide, which covers the drop. The conditions of the native oxide decomposition and the formation of the volatile Al2O suboxide strongly depend on the vacuum level during sessile drop experiments and the composition of the Cu-Al alloy. In our case, Al contents greater than 40% provides thermodynamic conditions for the formation of Al2O (as a result of Al reaction with Al2O3) and the drop spreading. It was suggested that the final contact angle in the Ta2O5/Cu-Al system (50°) is determined by Ta adsorption on the newly formed alumina interlayer.

Kish, Orel; Froumin, Natalya; Aizenshtein, Michael; Frage, Nachum

2014-05-01

376

Amyotrophic Lateral Sclerosis (ALS)  

Microsoft Academic Search

ALS, commonly called Lou Gehrig's disease, is a devastating neurological dis- order characterized by selective upper and lower somatic, but not autonomic, motor neurone degeneration leading to paralysis and eventually death. The diagnosis of ALS requires the presence of both upper and lower motor neu- rone degeneration and progressive motor dysfunction. ALS occurs in 1 to 2.5 cases per 100,000

Chris G. Parsons; Wojciech Danysz

377

Al-Anon/Alateen  

MedlinePLUS

... Alcoholism is a complex problem. More... How does Al-Anon Work? In Al-Anon, members do not give direction or advice to ... meeting? If someone else’s drinking troubles you, attending Al-Anon and Alateen Family Group meetings can help. More... ...

378

Materialforschung Buckypapers als Dehnungssensoren  

NASA Astrophysics Data System (ADS)

Kohlenstoff-Nanoröhrchen leiten elektrischen Strom wesentlich besser als Kupfer, sind zwanzigmal so zugfest wie Stahl und dabei äußerst elastisch und flexibel. Aufgrund dieser Eigenschaften gelten die nur wenige Nanometer dicken Röhrchen als aussichtsreicher Rohstoff für vielfältige technische Anwendungen - beispielsweise auch als elektromechanische Sensoren.

Leute, Angelika

2004-07-01

379

Microstructure and corrosion resistance of nanocrystalline TiZrN films on AISI 304 stainless steel substrate  

SciTech Connect

This study investigated the microstructure and properties of nanocrystalline TiZrN films on AISI 304 stainless steel substrate. TiZrN films were prepared by reactive magnetron sputtering based on the previous optimum coating conditions (substrate temperature, system pressure, nitrogen flow, etc.) for TiN and ZrN thin films. The composition ratio of TiZrN coatings were adjusted by changing the Zr target power, while keeping the Ti target power constant. Experiments were conduced to find the optimum composition with desired properties. The ratio of TiZrN composition was analyzed by x-ray photoelectron spectroscopy and Rutherford backscattering spectrometer. In terms of phase formation, there were two types of coatings that were considered: single-phase solid solutions of TiZrN and interlacing nuclei of TiZr in the matrix of TiZrN. The thickness of all TiZrN films as measured by the secondary ion mass spectroscopy was about 500 nm, and the composition depth profiles indicated that the compositions in the TiZrN films were uniform from the film surface to the 304 stainless steel substrate. The crystal structure of the TiZrN films was determined by x-ray diffraction using a M18XHF-SRA diffractometer with Cu K{sub {alpha}} radiation. A diffraction peak of TiZrN (002) was observed between that of TiN (002) and ZrN (002); similarly, a diffraction peak of TiZrN (111) was observed between that of TiN(111) and ZrN(111), respectively. The corrosion resistance of the TiZrN film deposited on the 304 stainless steel has been investigated by electrochemical measurement. The electrolyte, 0.5M H{sub 2}SO{sub 4} containing 0.05M KSCN, was used for the potentiodynamic polarization. The potentiodynamic scan was conducted from -800 to 800 mV standard calomel electrode (SCE).

Lin, Yu-Wei; Huang, Jia-Hong; Yu, Ge-Ping [Instrument Technology Research Center, 20 R and D Road VI, Hsinchu Science-Based Industrial Park, Hsinchu 300, Taiwan, Republic of China and Department of Engineering and System Science, National Tsing Hua University, 101 Kuang Fu Rd., Sec. 2, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Kuang Fu Rd., Sec. 2, Hsinchu 300, Taiwan (China); Department of Engineering and System Science, National Tsing Hua University, 101 Kuang Fu Rd., Sec. 2, Hsinchu 300, Taiwan, Republic of China and Institute of Nuclear Engineering and Science, National Tsing Hua University, 101 Kuang Fu Rd., Sec. 2, Hsinchu 300, Taiwan (China)

2010-07-15

380

TiAlN coatings deposited by triode magnetron sputtering varying the bias voltage  

NASA Astrophysics Data System (ADS)

TiAlN films were deposited on AISI O1 tool steel using a triode magnetron sputtering system. The bias voltage effect on the composition, thickness, crystallography, microstructure, hardness and adhesion strength was investigated. The coatings thickness and elemental composition analyses were carried out using scanning electron microscopy (SEM) together with energy dispersive X-ray (EDS). The re-sputtering effect due to the high-energy ions bombardment on the film surface influenced the coatings thickness. The films crystallography was investigated using X-ray diffraction characterization. The X-ray diffraction (XRD) data show that TiAlN coatings were crystallized in the cubic NaCl B1 structure, with orientations in the {1 1 1}, {2 0 0} {2 2 0} and {3 1 1} crystallographic planes. The surface morphology (roughness and grain size) of TiAlN coatings was investigated by atomic force microscopy (AFM). By increasing the substrate bias voltage from -40 to -150 V, hardness decreased from 32 GPa to 19 GPa. Scratch tester was used for measuring the critical loads and for measuring the adhesion.

Devia, D. M.; Restrepo-Parra, E.; Arango, P. J.; Tschiptschin, A. P.; Velez, J. M.

2011-05-01

381

Influence of nickel ion implantation on the inactive braze joining abilities of Al 2O 3 ceramics  

NASA Astrophysics Data System (ADS)

Multi-crystalline Al 2O 3 ceramics were implanted with 130 keV Ni + ion beams at 225 °C in a vacuum of 1.33 × 10 -3 Pa. The inactive braze joining abilities of the implanted ceramic to 1Cr18Ni9Ti (AISI 321) stainless steel with Ag 34Cu 16Zn 50 (wt%) brazing material were investigated. The relationships between the joining abilities and the surface compressive stresses produced by the ion implantation were studied for the first time. The results showed that when the fluence was less than 5 × 10 16 ions/cm 2, the surface properties including wetting ability, braze joining ability and produced surface compressive stresses, increased with ion implantation fluence, and reached the maximum value at a point of 5 × 10 16 ions/cm 2. After this point, the properties decreased upon further increasing the ion implantation fluence.

Zhao, B. R.; Li, G. B.; Gao, P.; Lei, T. Q.; Song, S. C.; Cao, X. J.

2005-09-01

382

ALS longitudinal kickers  

SciTech Connect

This paper discusses the coupled-bunch instability and how it applies to the ALS accelerator. The longitudinal ALS kicker is part of the bunch-to-bunch feedback system planned to control coupled-bunch instabilities in the ALS. The mechanical features of the kicker are described, and the analytic tools developed to aid in the design are discussed. A method to predict the performance of the kicker in the accelerator from measurements on a prototype are described.

Voelker, F.

1992-10-01

383

ALS - The cost cutter  

NASA Astrophysics Data System (ADS)

The Advanced Launch System (ALS) development program will avail itself of existing technologies in the short term in order to produce an interim 'core' vehicle that may be operational by 1993; the full, booster-incorporating system objective will then be achieved in 1998. This programmatic 'decoupling' of booster and core vehicle development efforts will separate their funding peaks. The ALS program will cut costs by colocating manufacturing and launch facilities, using Al-Li alloys in booster primary structures, and aggressively applying 'paperless' CIM. The ALS launch vehicle configuration will be primarily determined by both payload requirements and flight frequency.

Colucci, Frank

1987-10-01

384

Friction and wear of selected metals and alloys in sliding contact with AISI 440 C stainless steel in liquid methane and in liquid natural gas  

NASA Technical Reports Server (NTRS)

Aluminum, titanium, beryllium, nickel, iron, copper, and several copper alloys were run in sliding contact with AISI 440C in liquid methane and natural gas. All of the metals run except copper and the copper alloys of tin and tin-lead showed severely galled wear scars. Friction coefficients varied from 0.2 to 1.0, the lowest being for copper, copper-17 wt. % tin, and copper-8 wt. % tin-22 wt. % lead. The wear rate for copper was two orders of magnitude lower than that of the other metals run. An additional order of magnitude of wear reduction was achieved by the addition of tin and/or lead to copper.

Wisander, D. W.

1978-01-01

385

Microstructure and property modifications of an AISI H13 (4Cr5MoSiV) steel induced by pulsed electron beam treatment  

SciTech Connect

In the present work, surface modifications generated by the low energy high current pulsed electron beam (LEHCPEB) treatments have been investigated on an AISI H13 (4Cr5MoSiV) steel. From the observations of scanning electron microscopy, x-ray diffraction, and electron back scattering diffraction determinations, it could be established that the final structure in the melted layer is a mixture of ultrafine {delta} phase, martensite, and residual austenite. The formation of the heterogeneous microstructures on the surface layer is related to the very rapid heating, melting, solidification, and cooling induced by the LEHCPEB irradiation. After the LEHCPEB treatment, the wear resistance of the steel effectively improved. This can be mainly attributed to the higher hardness of the ultrafine structures formed on the top surface and the hardened subsurface layers after the treatment.

Zhang Kemin; Zou Jianxin; Grosdidier, Thierry; Dong Chuang [School of Materials Engineering, Shanghai University of Engineering Science, Shanghai 201620 (China); Shanghai Engineering Research Center of Mg Materials and Applications and School of Materials Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240 (China) and Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France); Laboratoire d'Etude des Textures et Applications aux Materiaux (LETAM, CNRS 3143), Universite Paul Verlaine Metz, Ile du Saulcy, 57045 Metz (France) and Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China); Laboratory of Materials Modification by Laser, Electron and Ion Beams, Dalian University of Technology, Dalian 116024 (China)

2010-11-15

386

Evaluation of boron mobility on the phases FeB, Fe 2B and diffusion zone in AISI 1045 and M2 steels  

NASA Astrophysics Data System (ADS)

The present study evaluates the growth kinetics of boride layers at the material surface on AISI 1045 and M2 steels during the paste boriding process. This surface hardening technique produces on the material two characteristic phases FeB, Fe 2B and a transition zone, denominated diffusion zone, in the layer/substrate interface. The thermochemical treatment was done at three different temperatures: 1193, 1223 and 1273 K with two treatment times: 2 and 6 h for the 1045 steel, and 1223, 1253 and 1273 K with the same treatment times for M2 steel, modifying the boron potentials in equilibrium at the substrates surfaces. Using the mass balance equation, and assuming a linear concentration profile at the interfaces, the mobility of boron was determined on both types of steels. The influence of boron potential, treatment time and temperatures is clearly observed on the growth kinetics of boride layers.

Campos, I.; Ramírez, G.; Figueroa, U.; Martínez, J.; Morales, O.

2007-01-01

387

Impact of localized surface preheating on the microstructure and crack formation in laser direct deposition of Stellite 1 on AISI 4340 steel  

NASA Astrophysics Data System (ADS)

Crack formation in laser cladding of the hardfacing alloy Stellite 1 on AISI-SAE 4340 steel was prevented through locally preheating the substrate prior to the deposition process. Numerical analysis showed that the preheating process helps developing a relatively steadier melt temperature as well as decreasing the cooling rates and consequently the thermal stresses during the subsequent deposition process. Microstructural analysis revealed a thicker cross-section with smoother surface profile, more uniform surface hardness and even distribution of a dendritic morphology in the preheated sample. This confirmed the presence of a well-developed melt pool with a homogeneous composition at solidification. The microstructure of non-preheated sample was, however, considerably non-uniform consisting of macro-scale colonies of dendritic and lamellar (eutectic) structures. The experimental observations, as implied through the numerical results, showed that the preheated sample, in general, reveals more uniform structure and properties making it less prone to cracking during the deposition process.

Fallah, Vahid; Alimardani, Masoud; Corbin, Stephen F.; Khajepour, Amir

2010-12-01

388

Determination of the AISI 1045 steel ablation threshold dependence on the pulse superposition using the Diagonal Scan (D-Scan) technique  

NASA Astrophysics Data System (ADS)

We report the use of the Diagonal Scan (D-Scan) technique to determine the ablation threshold of the AISI 1045 steel, a common engineering material that can be used as a probe for thermal effects, for superpositions ranging from single shot up to more than 10,000 pulses, for three pulses durations (25, 87 and 124 fs). It only took two hours of laboratory time to determine more than 20 ablation thresholds per pulse duration spanning 4 orders of magnitude of superpositions. The large amount of data generated shows a small deviation of the ablation threshold from the expected behavior, which can lead to the use of a model that better describes the dynamics of the ultrashort pulses ablation mechanism in metals.

Samad, Ricardo E.; Mirim, Denílson C.; de Rossi, Wagner; Vieira, Nilson D.

2014-03-01

389

Combined bending-torsion fatigue reliability of AISI 4340 steel shafting with K sub t = 2.34. [stress concentration factor  

NASA Technical Reports Server (NTRS)

Results generated by three, unique fatigue reliability research machines which can apply reversed bending loads combined with steady torque are presented. Six-inch long, AISI 4340 steel, grooved specimens with a stress concentration factor of 2.34 and R sub C 35/40 hardness were subjected to various combinations of these loads and cycled to failure. The generated cycles-to-failure and stress-to-failure data are statistically analyzed to develop distributional S-N and Goodman diagrams. Various failure theories are investigated to determine which one represents the data best. The effect of the groove and of the various combined bending-torsion loads on the S-N and Goodman diagrams are determined. Three design applications are presented. The third one illustrates the weight savings that may be achieved by designing for reliability.

Kececioglu, D.; Chester, L. B.; Dodge, T. M.

1974-01-01

390

Effect of cathodic hydrogenation on the mechanical properties of AISI 304 stainless steel nitrided by ion implantation, glow discharge and plasma immersion ion implantation  

NASA Astrophysics Data System (ADS)

Hydrogen embrittlement in austenitic stainless steels is restricted to the surface due to the low hydrogen diffusion in austenitic structures. The effect of three different nitriding processes: ion implantation (II), plasma immersion ion implantation (PI3) and glow discharge (GD), on the mechanical and structural properties of cathodically hydrogenated AISI 304 stainless steel were studied in the present work. Cathodic hydrogenation was made on untreated and nitrided samples. Surface microstructure after nitriding and hydrogenation was investigated by X-ray diffraction. Mechanical properties were measured by instrumented indentation. Surface crack formation and hardness decrease was observed in non-nitrided samples after cathodic hydrogenation. Hardness of nitrided samples decreases after hydrogen degassing but still has values higher than untreated samples. Comparative analysis of nitriding processes and working conditions indicated that glow discharge plasma nitriding process at 400 °C or 450 °C is the most adequate to avoid crack formation in steel surface after cathodic hydrogenation.

Foerster, C. E.; Souza, J. F. P.; Silva, C. A.; Ueda, M.; Kuromoto, N. K.; Serbena, F. C.; Silva, S. L. R.; Lepienski, C. M.

2007-04-01

391

AISI Direct Steelmaking Program  

SciTech Connect

Pilot plant trials with the horizontal vessel were completed. Design of a third pressurized vessel and an offgas cleaning and tempering system was completed. Installation is now underway. A basic study and a pre-engineering design of a 350,000-metric ton/y demonstration plant were completed, and efforts are underway to develop such a demonstration plant at a host steel company. Foreign filings have been prepared for the two-zone countercurrent smelter (patent applied for). Work with a water model of two-zone smelter was completed. The horizontal smelter program was completed. Trials were conducted to determine how sulfur is partitioned among the hot metal, slag, and offgas. Design of offgas cleaning and tempering loop was completed.

Aukrust, E.

1993-01-01

392

ALS: AN ETHICAL PERSPECTIVE  

Microsoft Academic Search

Amyotrophic lateral sclerosis (ALS), or Lou Gehrig's disease, is a relentlessly progressive, fatal and presently incurable motor neuron disorder caused by degeneration of both upper and lower neurons that control voluntary skeletal muscle. ALS variants include a progressive lower motor neuron disorder, Progressive Muscular Atrophy (PMA); a progressive upper motor neuron disorder, Primary Lateral Sclerosis (PLS); and a progressive disorder

Leo McCluskey

393

About ALS: FAQ  

MedlinePLUS

... on this web site. "Recent studies in the transgenic animal models of ALS (model of familial ALS) provide evidence that creatine is effective in protecting degenerating motor neurons and delaying disease deterioration in these mice. Clinical trials are of the utmost importance to ...

394

[Phenotypic variation in ALS].  

PubMed

Making a diagnosis of typical amyotrophic lateral sclerosis (ALS) is not a tough job, but when it comes to atypical forms of motor neuron disease (MND) which are not uncommon in clinical setting, we may have some difficulty to diagnose ALS/MND. There is striking phenotypic variation in sporadic ALS/MND, such as frail arm syndrome (brachial amyotrophic diplegia), pseudopolyneuritic form, hemiplegic type, ALS/MND with markedly extended involvement beyond the motor system, and MND with basophilic inclusion bodies. These variations must be recognized if physicians are to tailor advice on disease progression, prognosis, drug therapy, and care to the needs of the individual. Clinical trials of new therapeutic agents have been performed, on the assumption that patients with ALS/MND have the same underlying etiology, addressing the heterogeneous population of the patients under a single diagnostic category. This can be detrimental to the well-being of the individual, because clinical heterogeneity may mask drug effects in clinical trials. The attempt to categorize subgroups based on the clinical and pathological backgrounds within the spectrum of ALS/MND may be a critical step in facilitating clinical research in ALS/MND. Definition of clinicopathologic syndromes in patients with ALS/MND is an important challenging task that cannot be ignored. PMID:17432191

Sasaki, Shoichi

2006-11-01

395

[Environmental factors in ALS].  

PubMed

ALS is likely to be a disorder of multifactorial origin. Among all the factors that may increase the risk of ALS, environmental ones are being studied for many years, but in the recent years, several advances have pointed to a new interest in their potential involvement in the disease process, especially for the cyanotoxin BMAA. Food containing BMAA has been found on Guam, a well-known focus of ALS/parkinsonism/dementia and high levels of BMAA have been identified into the brain of these patients. The BMAA cyanotoxin is potentially ubiquitous and have also been found into the food of patients who died from ALS both in Europe and USA. BMAA can be wrongly integrated into the protein structure during mRNA traduction, competing with serine. This may induce abnormal protein folding and a subsequent cell death. Heavy metals, such as lead or mercury may be directly toxic for neuronal cells. Several works have suggested an increased risk of ALS in individuals chronically exposed to these metals. Exposure to pesticides has been suggested to be linked to an increased risk of developing ALS. The mechanism of their toxicity is likely to be mediated by paraoxonases. These proteins are in charge of detoxifying the organism from toxins, and particularly organophosphates. To date, there are insufficient scientific data to suggest that exposure to electromagnetic fields may increase the risk of having ALS. We are particularly missing longitudinal cohorts to demonstrate that risk. PMID:24703731

Juntas-Morales, Raul; Pageot, Nicolas; Corcia, Philippe; Camu, William

2014-05-01

396

Effect of different micro-plasma arc welding (MPAW) processes on the corrosion of AISI 316L SS tubes in LiBr and H 3PO 4 solutions under flowing conditions  

Microsoft Academic Search

This work studies the corrosion under flowing conditions of four kinds of AISI 316L materials welded by the micro-plasma arc welding technique in different media: a basic (LiBr) and an acidic (H3PO4) solution by means of polarization measurements. Sensitization tests, galvanic corrosion evaluation, microstructural analyses and microhardness tests have been also carried out. Corrosion parameters revealed that, among the materials

R. Sánchez-Tovar; M. T. Montañés; J. García-Antón

2010-01-01

397

Study on the effects of pulsed TIG welding parameters on delta-ferrite content, shape factor and bead quality in orbital welding of AISI 316L stainless steel plate  

Microsoft Academic Search

The TIG pulse welding parameters of AISI 316L stainless steel plate of 3mm thickness at the welding positions of 6–12h were investigated. The weld bead profiles corresponded to DIN 8563 class BS. The studied parameters were welding speed, pulse\\/base currents, pulse frequency, and % on time. Pure argon and argon with nitrogen contents of 1–4vol.% were used as shielding gas

G Lothongkum; E Viyanit; P Bhandhubanyong

2001-01-01

398

Initial Symptoms of ALS  

MedlinePLUS

... Symptoms can begin in the muscles of speech, swallowing or in the hands, arms, legs or feet. Not all people with ALS experience the same symptoms or the same sequences or patterns of progression. But, progressive muscle weakness and paralysis ...

399

Primary AL Amyloidosis  

MedlinePLUS

... AL amyloidosis is a hematological disorder, associated with plasma cell dyscrasia that means an abnormal condition of ... fibrils, formed by an errant (monoclonal) group of plasma cells in the bone marrow, consist of abnormal ...

400

Isokinetic assessment in ALS.  

PubMed

Three measures of lower extremity function were compared in a homogenous population of ALS patients. Isokinetic dynamometry was shown to be a sensitive tool for change in strength over time. It demonstrated positive correlations with gait velocity as well as other behavioral measures. Manual muscle tests were relatively insensitive and no more reliable than isokinetics. Isokinetics are a useful adjunct in the assessment of ALS. PMID:11681399

Sufit, R; Clough, J A; Schram, M; Conrad, J; Erickson, L; Brooks, B R

1987-05-01

401

MoB/CoCr Cermet Coatings by HVOF Spraying against Erosion by Molten Al-Zn Alloy  

NASA Astrophysics Data System (ADS)

MoB/CoCr, a novel cermet material for thermal spraying, with high durability in molten alloys has been developed to utilize for aluminum die-casting parts, and for hot continuous dipping rolls in Zn and Al-Zn plating lines. The durability of the MoB/CoCr coatings prepared by high velocity oxy-fuel (HVOF) spraying has been investigated using a molten-metal immersion tester. The tests revealed that the MoB/CoCr coating has much higher durability without dissolution in the molten Al-45wt.%Zn alloy. Little change of crystal structure, mainly composed of double borides of CoMoB and CoMo2B2, is observed after the immersion test, suggesting that the double borides have much higher durability. Using undercoat is effective to reduce the influence of large difference in thermal expansion between the MoB/CoCr topcoat and substrate of stainless steel of AISI 316L, widely used for the hot continuous dipping rolls. Optimized thickness combinations of topcoat and undercoat are necessary to obtain intrinsic performance of low reactive MoB/CoCr against the molten Al-45wt.%Zn alloy.

Mizuno, Hiroaki; Kitamura, Junya

2007-09-01

402

Al Qaeda Training Manual  

NSDL National Science Digital Library

The first resource is a US Department of Justice release of portions of an English translation of the Al Qaeda training manual located by police in Manchester, England during a search of an Al Qaeda member's home. The manual was found in a computer file described as "the military series" related to the "Declaration of Jihad." The cover and excerpts from the 12 chapters can be viewed as a .pdf file. Content of the text includes religious commentary, organizational tactics, guidelines for member selection, techniques for spying, and security measures. The DOJ does not provide the entire document because it does not want to encourage terrorism.

2001-01-01

403

The effect of substrate bias voltages on impact resistance of CrAlN coatings deposited by modified ion beam enhanced magnetron sputtering  

NASA Astrophysics Data System (ADS)

CrAlN coatings were deposited on silicon and AISI H13 steel substrates using a modified ion beam enhanced magnetron sputtering system. The effect of substrate negative bias voltages on the impact property of the CrAlN coatings was studied. The X-ray diffraction (XRD) data show that all CrAlN coatings were crystallized in the cubic NaCl B1 structure, with the (1 1 1), (2 0 0) (2 2 0) and (2 2 2) diffraction peaks observed. Two-dimensional surface morphologies of CrAlN coatings were investigated by atomic force microscope (AFM). The results show that with increasing substrate bias voltage the coatings became more compact and denser, and the microhardness and fracture toughness of the coatings increased correspondingly. In the dynamic impact resistance tests, the CrAlN coatings displayed better impact resistance with the increase of bias voltage, due to the reduced emergence and propagation of the cracks in coatings with a very dense structure and the increase of hardness and fracture toughness in coatings.

Chunyan, Yu; Linhai, Tian; Yinghui, Wei; Shebin, Wang; Tianbao, Li; Bingshe, Xu

2009-01-01

404

ALS renewal moves forward  

NASA Astrophysics Data System (ADS)

As the result of an extensive long-term planning process involving all its stakeholders—management, staff, and users—the ALS has seen its future and is aggressively moving ahead to implement its vision for keeping the facility at the cutting edge for the next 2-3 decades. The evolving strategic plan now in place aims to renew the ALS so it can address a new generation of fundamental questions about size dependent and dimensional-confinement phenomena at the nanoscale; correlation and complexity in physical, biological, and environmental systems; and temporal evolution, assembly, dynamics and ultrafast phenomena. The renewal spans three areas: (1) increased staffing at beamlines to support the growing user community and safety professionals to keep an increasingly complex facility hazard free; (2) implementing advances in accelerator, insertion device, beamline, and detector technology that will make it possible for ALS users to address emerging grand scientific and technological challenges with incisive world-class tools; and (3) construction of a user support building and guest housing that will increase the safety and user friendliness of the ALS by providing users office, meeting, experiment staging, and laboratory space for their work and on-site accommodations at reasonable rates.

Falcone, R. W.; Feinberg, B.; Hussain, Z.; Kirz, J.; Krebs, G. F.; Padmore, H. A.; Robin, D. S.; Robinson, A. L.

2007-11-01

405

Al Shanker Remembers.  

ERIC Educational Resources Information Center

In a 1996 interview shortly before his death, Al Shanker, longtime president of the American Federation of Teachers, discussed such topics as: his own educational experiences; how he learned about political fighting in the Boy Scouts; the appeal of socialism; multinational corporations and the nation state; teaching tough students; and John Dewey…

American Educator, 2000

2000-01-01

406

Determinacion de Cr, Mn, Si y Ni en aceros al carbono por analisis espectral de emision con fuente de chispa. (Determination of Cr, Mn, Si, and Ni in carbon steels by optical emission spectrometry with spark source).  

National Technical Information Service (NTIS)

Elemental composition of steels determines some important of his characteristic moreover it is necessary to obtain their quality certification. Analytical procedure has performed for determination of Cr, Mn, Si and Ni in carbon steels by optical emission ...

M. A. Garcia Gonzalez M. Pomares Alfonso L. Mora Lopez

1995-01-01

407

In-situ measurements of the oxidation of AISI 316L(NG) and its constituents (Fe,Cr, Ni) in ultra-supercritical water  

SciTech Connect

Several new nuclear reactor designs utilizing supercritical water as coolant are currently being developed. In the European concept the design pressure is 25 MPa and reactor inlet/outlet temperatures 290 deg C/520 deg C. While benefits include better coolant thermal conductivity, increase in efficiency and simpler overall design, many material related questions need to be solved such as oxidation and radiation resistance with simultaneous need to maintain creep strength. This calls for the development of in-situ monitoring methods for the material/environment combination in question. In the present paper, in-situ electrical and electrochemical measurements during oxidation of AISI 316L(NG) and its pure metal constituents (Fe,Cr and Ni) in ultra-supercritical water (500-700 deg C, 30 MPa) have been reproducibly obtained. The oxidation kinetics was followed using the contact electric resistance (CER) and contact electric impedance (CEI) techniques. First attempts have been made to correlate properties of the resulting oxides with the corresponding weight gain data. In addition, impedance spectra of the Ni-Ni contact during oxidation have been reproducibly measured at 500 and 600 deg C. They could be quantitatively interpreted using general considerations of the corrosion process and the Mixed-Conduction Model for oxide films. Preliminary estimates of the diffusion coefficients of principal ionic and electronic current carriers have been obtained and their relevance with respect to available data on Ni oxidation is discussed. (authors)

Betova, Iva [Institute of Electrochemistry and Energy Systems, Bulgarian Academy of Science, 1113 Sofia (Bulgaria); Bojinov, Martin [Department of Physical Chemistry, University of Chemical Technology and Metallurgy, 1756 Sofia (Bulgaria); Kinnunen, Petri; Lehtovuori, Viivi; Peltonen, Seppo; Penttila, Sami; Saario, Timo [VTT Materials and Building, Technical Research Centre of Finland, P.O.Box 1000, FIN-02044 VTT, Espoo (Finland)

2006-07-01

408

Influence of Surface Position along the Working Range of Conoscopic Holography Sensors on Dimensional Verification of AISI 316 Wire EDM Machined Surfaces  

PubMed Central

Conoscopic holography (CH) is a non-contact interferometric technique used for surface digitization which presents several advantages over other optical techniques such as laser triangulation. Among others, the ability for the reconstruction of high-sloped surfaces stands out, and so does its lower dependence on surface optical properties. Nevertheless, similarly to other optical systems, adjustment of CH sensors requires an adequate selection of configuration parameters for ensuring a high quality surface digitizing. This should be done on a surface located as close as possible to the stand-off distance by tuning frequency (F) and power (P) until the quality indicators Signal-to-Noise Ratio (SNR) and signal envelope (Total) meet proper values. However, not all the points of an actual surface are located at the stand-off distance, but they could be located throughout the whole working range (WR). Thus, the quality of a digitized surface may not be uniform. The present work analyses how the quality of a reconstructed surface is affected by its relative position within the WR under different combinations of the parameters F and P. Experiments have been conducted on AISI 316 wire EDM machined flat surfaces. The number of high-quality points digitized as well as distance measurements between different surfaces throughout the WR allowed for comparing the metrological behaviour of the CH sensor with respect to a touch probe (TP) on a CMM.

Fernandez, Pedro; Blanco, David; Rico, Carlos; Valino, Gonzalo; Mateos, Sabino

2014-01-01

409

In vitro corrosion study by EIS of an equiatomic NiTi alloy and an implant quality AISI 316 stainless steel.  

PubMed

The electrochemical impedance spectroscopy (EIS) technique was used for the study of the electrochemical behavior of an equiatomic NiTi alloy and an implant quality AISI 316 stainless steel type ASTM F138. Experiments were carried out using four different different test solutions: phosphate buffered saline (PBS), Dulbecco minimum essential medium (MEM), MEM + fetal calf serum (FCS), and MEM + fetal calf serum + fibroblast cell (CELL). Specimens were finished to 600-grit SiC paper and were tested in conditions that did not provoke abrupt mechanical damage of the passive film. Bode-phase spectra showed the presence of two maxima and were fitted with an equivalent circuit characterized by two parallel combinations (R, resistance; CPE, constant phase element). The R(1) and CPE(1) branch was assigned to the inner compact passive film and the R(2) and CPE(2) branch to the external porous film. The resistance of the inner film R(1), roughly corresponding to the polarization resistance (R(p)), which is inversely proportional to the material's corrosion rate, increased with the immersion time and was generally greater in PBS than in other media. With the exception of FCS solution, R(1) for NiTi alloy is better or similar to that of ASTM F138. PMID:16850480

Rondelli, G; Torricelli, P; Fini, M; Rimondini, L; Giardino, R

2006-11-01

410

Prediction of scuffing failure based on competitive kinetics of oxide formation and removal: Application to lubricated sliding of AISI 52100 steel on steel  

NASA Astrophysics Data System (ADS)

A method for predicting scuffing failure based on the competitive kinetics of oxide formation and removal has been developed and applied to the sliding of AISI 52100 steel on steel with poly-alpha-olefin as the lubricant. Oxide formation rates were determining using static oxidation tests on coupons of 52100 steel covered with poly-alpha-olefin at temperatures of 140 C to 250 C. Oxide removal rates were determined at different combinations of initial average nominal contact pressures (950 MPa to 1578 MPa) and sliding velocities (0.4 m/s to 1.8 m/s) using a ball-on-disk vacuum tribotester. The nominal asperity flash temperatures generated during the wear tests were calculated and the temperatures corresponding to the intersection of the the Arrhenius plots of oxide formation and removal rates were determined and taken as the critical failure temperatures. The pressure-velocity failure transition diagram was constructed by plotting the critical failure temperatures along isotherms of average nominal asperity flash temperatures calculated at different combinations of contact stress and sliding speed. The predicted failure transition curve agreed well with experimental scuffing data.

Cutiongco, Eric C.; Chung, Yip-Wah

1994-07-01

411

Surface properties of nitrided layer on AISI 316L austenitic stainless steel produced by high temperature plasma nitriding in short time  

NASA Astrophysics Data System (ADS)

It has generally been believed that the formation of the S phase or expanded austenite ?N with enough thickness depends on the temperature (lower than 480 °C) and duration of the process. In this work, we attempt to produce nitrogen expanded austenite layer at high temperature in short time. Nitriding of AISI 316L austenitic stainless steel was carried out at high temperatures (>520 °C) for times ranging from 5 to 120 min. The microstructures, chemical composition, the thickness and the morphology of the nitrided layer, as well as its surface hardness, were investigated using X-ray diffraction, X-ray photoelectron spectroscopy, optical microscopy, scanning electron microscopy, and microhardness tester. The corrosion properties of the untreated and nitrided samples were evaluated using anodic polarization tests in 3.5% NaCl solution. The results confirmed that nitrided layer was shown to consist of ?N and a small amount of free-CrN and iron nitrides. High temperature plasma nitriding not only increased the surface hardness but also improved the corrosion resistance of the austenitic stainless steel, and it can critically reduce processing time compared with low temperature nitriding.

Li, Yang; Wang, Zhuo; Wang, Liang

2014-04-01

412

The effect of gas mixture of post-oxidation on structure and corrosion behavior of plasma nitrided AISI 316 stainless steel  

NASA Astrophysics Data System (ADS)

In this research, microstructure and corrosion properties of plasma nitriding and post-oxidation treated AISI 316 austenitic stainless steel have been studied. The plasma nitriding treatment was carried out at 450 °C for 5 h in a D.C. plasma setup with a gas mixture of 25% N2-75% H2 followed by post-oxidation in gas mixtures of O2/H2: 1/3, 1/5, 1/9 and 1/12 for 30 min. The treated samples were characterized by SEM, XRD and roughness testing. Potentiodynamic and cyclic polarization tests were also employed to evaluate the corrosion resistance of the samples. The results showed that plasma nitriding treatment decreases corrosion resistance of the steel substrate. However, post-oxidizing treatment improves both uniform and pitting corrosion resistances of the nitrided specimens. This effect was most pronounced by post-oxidizing at lower O2/H2 ratios due to the development of magnetite as a more dense oxide phase over the modified layer.

Karimzadeh, N.; Moghaddam, E. G.; Mirjani, M.; Raeissi, K.

2013-10-01

413

The Effect of Surface Roughness on the Corrosion Properties of Type AISI 304 Stainless Steel in Diluted NaCl and Urban Rain Solution  

NASA Astrophysics Data System (ADS)

Due to their good corrosion resistance, favorable mechanical properties, and reasonable price regarding their excellent properties, austenitic stainless steels have, over recent decades, become one of the alloys that are increasingly used in civil engineering and building, as well as for specific architectural purposes. Architects often design stainless steel exterior elements with higher surface roughnesses, which are not resistant to corrosion processes. The aim of this work was to investigate the influence of different types of surface finishes to stainless steel of quality AISI 304 on the corrosion properties of this steel. In order to achieve this goal, electrochemical tests were performed on different surface finishes in two different environments: in an NaCl aqueous solution, and in simulated urban rain which contained no chlorides. In addition to the electrochemical methods used, surface roughness was also measured, and XPS surface analyses were performed. The results of the investigation showed that surface roughness affects the growth of the passive layer in urban rain significantly; however, the growth of such a film is retarded in the case of the NaCl aqueous solution. Based on the results of the performed analyses, it was found that, in the NaCl solution, the pitting potential depended strongly upon the surface roughness and the surface finish, but this was not true for the samples tested in urban rain.

Leban, Mirjam Bajt; Mikyška, ?rt; Kosec, Tadeja; Markoli, Boštjan; Kova?, Janez

2014-05-01

414

Corrosion of nickel—chromium deposit on AISI 316L stainless steel in radioactive water with and without fluoride at pH 4  

NASA Astrophysics Data System (ADS)

The electrochemical behavior of samples was studied using potentiodynamic techniques at low scan rates, cyclic voltammetry at high scan rates and electrochemical impedance spectroscopy. The surfaces were examined and analyzed by scanning electron microscopy and X-ray microanalysis, respectively. The results from these different methods are discussed. They show that the deposit is more easily corroded than the AISI 316L stainless steel in presence or absence of fluoride. With fluoride and at the prepassive potentials, the Warburg straight line indicates that there is ionic diffusion in the nickel—chromium deposit oxide. The equivalent circuits for the nickel-chromium are proposed and indicate that the deposit can take part in localized corrosion. The use of high scan rates shows the transient kinetics of the oxide formation in presence of fluoride. With fluoride, the pitting currents are higher for nickel-chromium deposits. The SEM photographs and polarization curves show that the Ni?Cr deposit is locally corroded by fluoride, leading to the possibility of crevice formation under this and in 316L stainless steel.

Bellanger, G.; Rameau, J. J.

1995-10-01

415

ALS insertion devices  

SciTech Connect

The Advanced Light Source (ALS), the first US third generation synchrotron radiation source, is currently under construction at the Lawrence Berkeley Laboratory. The low-emittance, 1.5 GeV electron storage ring and the insertion devices are specifically designed to produce high brightness beams in the UV to soft X-Ray range. The planned initial complement of insertion devices includes four 4.6 m long undulators, with period lengths of 3.9 cm, 5.0 cm (2) and 8.0 cm, and a 2.9 m long wiggler of 16 cm period length. Undulator design is well advanced and fabrication has begun on the 5.0 cm and 8.0 cm period length undulators. This paper discusses ALS insertion device requirements; general design philosophy; and design of the magnetic structure, support structure/drive systems, control system and vacuum system. 18 refs., 9 figs., 5 tabs.

Hoyer, E.; Chin, J.; Halbach, K.; Hassenzahl, W.V.; Humphries, D.; Kincaid, B.; Lancaster, H.; Plate, D.

1990-11-01

416

Al Parker: American Illustrator  

NSDL National Science Digital Library

This tribute to Al Parker, the noted magazine illustrator and artist, was fashioned from extensive holdings at the Washington University Library in St. Louis. Known as "The Dean of Illustrators," Al Parker attended school at the St. Louis School of Fine Arts at Washington University and went on to become of the most prolific and important American illustrators of the twentieth century. Parker was best-known for his modernist deployment of line, patterning, and bold, flat colors, which helped shape the general "look" of the period from the 1930s to the 1960s. Using short clips of Parker's original illustrations and drawings, this exhibit offers a glimpse into his work and contributions to the medium. Of particular interest is the section devoted to Parker's famous "Mother-Daughter" covers for the Ladies Home Journal, which began in 1939 and ran for 17 years.

2001-01-01

417

Jasechko et al. reply.  

PubMed

replying to A. M. J. Coenders-Gerrits et al. 506, http://dx.doi.org/10.1038/nature12925 (2014)In their Comment, Coenders-Gerrits et al. suggest that our conclusion that transpiration dominates the terrestrial water cycle is biased by unrepresentative input data and optimistic uncertainty ranges related to runoff, interception and the isotopic compositions of transpired and evaporated moisture. We clearly presented the uncertainties applied in our Monte-Carlo sensitivity analysis, we reported percentile ranges of results rather than standard deviations to best communicate the nonlinear nature of the isotopic evaporation model, and we highlighted that the uncertainty in our calculation remains large, particularly in humid catchments (for example, figure 2 in our paper). PMID:24522604

Jasechko, Scott; Sharp, Zachary D; Gibson, John J; Birks, S Jean; Yi, Yi; Fawcett, Peter J

2014-02-13

418

ALS Project Management Manual  

SciTech Connect

This manual has been prepared to help establish a consistent baseline of management practices across all ALS projects. It describes the initial process of planning a project, with a specific focus on the production of a formal project plan. We feel that the primary weakness in ALS project management efforts to date stems from a failure to appreciate the importance of ''up-front'' project planning. In this document, we present a guide (with examples) to preparing the documents necessary to properly plan, monitor, and control a project's activities. While following the manual will certainly not guarantee good project management, failure to address the issues we raise will dramatically reduce the chance of success. Here we define success as meeting the technical goals on schedule and within the prescribed budget.

Krupnick, Jim; Harkins, Joe

2000-05-01

419

Characterization and optimization of pulse electrodeposition of Ni/nano-Al2O3 composite coatings  

NASA Astrophysics Data System (ADS)

Nickel/nano-Al2O3 composite coatings produced by the pulse electrodeposition method and the influence of pulse parameters, i.e., pulse frequency, duty cycle, and current density on the microstructure, hardness, and corrosion resistance, were critically investigated on an AISI 1018 mild steel specimen electroplated in a Watt's type bath. The experiments were carried out with different combinations of pulse parameters using Taguchi's L27 orthogonal array, and 27 trials were conducted to study the effect of pulse parameters in view to maximize the hardness of the specimen. The assessment results clearly reveal that the specimen exhibits the maximum hardness at the pulse frequency of 20 Hz, duty cycle of 30%, and peak current density of 0.4 A/cm2, which are designated as the optimal parameters herein. Furthermore, the influences of those optimized pulse parameters over the microstructure and corrosion resistance were investigated, and some conclusions were drawn. Also, from the ANOVA examination, it is clear that duty cycle is predominant in affecting the hardness, while current density has relatively low impact.

Jegan, A.; Venkatesan, R.

2013-05-01

420

Mechanical, tribological, and electrochemical behavior of Cr 1- xAl xN coatings deposited by r.f. reactive magnetron co-sputtering method  

NASA Astrophysics Data System (ADS)

Chromium aluminum nitride (Cr 1- xAl xN) coatings were deposited onto AISI H13 steel and silicon substrates by r.f. reactive magnetron co-sputtering in (Ar/N 2) gas mixture from chromium and aluminum targets. Properties of deposited Cr 1- xAl xN coatings such as compositional, structural, morphological, electrochemical, mechanical and tribological, were investigated as functions of aluminum content. X-ray diffraction patterns of Cr 1- xAl xN coatings with different atomic concentrations of aluminum (0.51 < x < 0.69) showed the presence and evolution of (1 1 1), (2 0 0), and (1 0 2) crystallographic orientations associated to the Cr 1- xAl xN cubic and w-AlN phases, respectively. The rate of corrosion of the steel coated with Cr 1- xAl xN varied with the applied power; however, always being clearly lower when compared to the uncoated substrate. The behavior of the protective effect of the Cr 1- xAl xN coatings is based on the substitution of Cr for Al, when the power applied to the aluminum target increases. The mechanical properties were also sensitive to the power applied, leading to a maximum in hardness and a reduced elastic modulus of 30 and 303 GPa at 350 W and a monotonic decrease to 11 and 212 GPa at 450 W, respectively. Finally, the friction coefficient measured by pin-on disk revealed values between 0.45 and 0.70 in humid atmosphere.

Sanchéz, J. E.; Sanchéz, O. M.; Ipaz, L.; Aperador, W.; Caicedo, J. C.; Amaya, C.; Landaverde, M. A. Hernández; Beltran, F. Espinoza; Muñoz-Saldaña, J.; Zambrano, G.

2010-02-01

421

AL Users' Manual. Third Edition.  

National Technical Information Service (NTIS)

AL is a high-level programming language for manipulator control useful in industrial assembly research. The document describes the current state of the AL system now in operation at the Stanford Artificial Intelligence Laboratory, and teaches the reader h...

S. Mujtaba R. Goldman

1981-01-01

422

Laser welding of NiTi shape memory alloy: Comparison of the similar and dissimilar joints to AISI 304 stainless steel  

NASA Astrophysics Data System (ADS)

The unique properties of NiTi alloy, such as its shape memory effect, super-elasticity and biocompatibility, make it ideal material for various applications such as aerospace, micro-electronics and medical device. In order to meet the requirement of increasing applications, great attention has been given to joining of this material to itself and to other materials during past few years. Laser welding has been known as a suitable joining technique for NiTi shape memory alloy. Hence, in this work, a comparative study on laser welding of NiTi wire to itself and to AISI 304 austenitic stainless steel wire has been made. Microstructures, mechanical properties and fracture morphologies of the laser joints were investigated using optical microscopy, scanning electron microscopy (SEM), energy dispersive spectroscopy (EDS), X-ray diffraction analysis (XRD), Vickers microhardness (HV0.2) and tensile testing techniques. The results showed that the NiTi–NiTi laser joint reached about 63% of the ultimate tensile strength of the as-received NiTi wire (i.e. 835 MPa) with rupture strain of about 16%. This joint also enabled the possibility to benefit from the pseudo-elastic properties of the NiTi component. However, tensile strength and ductility decreased significantly after dissimilar laser welding of NiTi to stainless steel due to the formation of brittle intermetallic compounds in the weld zone during laser welding. Therefore, a suitable modification process is required for improvement of the joint properties of the dissimilar welded wires.

Mirshekari, G. R.; Saatchi, A.; Kermanpur, A.; Sadrnezhaad, S. K.

2013-12-01

423

Al Jazirah, Sudan  

NASA Technical Reports Server (NTRS)

Al Jazirah (also Gezira) is one of the 26 states of Sudan. The state lies between the Blue Nile and the White Nile in the east-central region of the country. It is a well populated area suitable for agriculture. The area was at the southern end of Nubia and little is known about its ancient history and only limited archaeological work has been conducted in this area. The region has benefited from the Gezira Scheme, a program to foster cotton farming begun in 1925. At that time the Sennar Dam and numerous irrigation canals were built. Al Jazirah became the Sudan's major agricultural region with more than 2.5 million acres (10,000 km) under cultivation. The initial development project was semi-private, but the government nationalized it in 1950. Cotton production increased in the 1970s but by the 1990s increased wheat production has supplanted a third of the land formerly seeded with cotton.

The image was acquired December 25, 2006, covers an area of 56 x 36.4 km, and is located near 14.5 degrees north latitude, 33.1 degrees east longitude.

The U.S. science team is located at NASA's Jet Propulsion Laboratory, Pasadena, Calif. The Terra mission is part of NASA's Science Mission Directorate.

2008-01-01

424

Al Mashriq: Lebanon  

NSDL National Science Digital Library

Part of the Al-Mashriq online Web resource for countries located in the Levant, this site is devoted to providing a host of materials, thematically organized, about the country of Lebanon. Persons seeking to read a bit about Lebanon's early history will want to read the first chapter of Kamal Salibi's "A House of Many Mansions-The History of Lebanon," which is provided here. For those looking for a geographic orientation to the landscape of Lebanon, an interactive map provides a number of photographs and brief remarks on various important cities and cultural sites, such as Beirut and the Roman temples at Baalbak. Along with these sections, the site also offers thematic sections devoted to education, food, maps, money, politics, and religion that will be useful to those students looking for background information on Lebanon.

425

Doppelthydrophile Blockcopolymere als Mineralisationstemplate  

NASA Astrophysics Data System (ADS)

Die vorliegende Arbeit beschäftigt sich mit der Synthese und den Eigenschaften von doppelthydrophilen Blockcopolymeren und ihrer Anwendung in einem biomimetischen Mineralisationsprozeß von Calciumcarbonat und Bariumsulfat. Doppelthydrophile Blockcopolymere bestehen aus einem hydrophilen Block, der nicht mit Mineralien wechselwirkt und einem zweiten Polyelektrolyt-Block, der stark mit Mineraloberflächen wechselwirkt. Diese Blockcopolymere wurden durch ringöffnende Polymerisation von N-carboxyanhydriden (NCA's) und a-methoxy-?-amino[poly(ethylene glycol)] PEG-NH2 als Initiator hergestellt. Die hergestellten Blockcopolymere wurden als effektive Wachstumsmodifikatoren für die Kristallisation von Calciumcarbonat und Bariumsulfat Mineralien eingesetzt. Die so erhaltenen Mineralpartikel (Kugeln, Hantel, eiförmige Partikel) wurden durch Lichtmikroskopie in Lösung, SEM und TEM charakterisiert. Röntgenweitwinkelstreuung (WAXS) wurde verwendet, um die Modifikation von Calciumcarbonat zu ermitteln und die Größe der Calciumcarbonat- und Bariumsulfat-Nanopartikel zu ermitteln. This work describes the synthesis and characterization of double hydrophilic block copolymers and their use in a biomimetic mineralization process of Calcium Carbonate and Barium Sulfate. Double hydrophilic block copolymers consist of a hydrophilic block that does not interact with minerals and another hydrophilic polyelectrolyte block that strongly interacts with mineral surfaces. These polymers were synthesised via ring opening polymerisation of N-carboxyanhydride (NCA), and the first hydrophilic block a-methoxy-?-amino[poly(ethylene glycol)] PEG-NH2 was used as an initiator. The prepared block copolymers were used as effective crystal growth modifiers to control the crystallization of Calcium Carbonate and Barium Sulfate minerals. The resulting mineral particles (spheres, dumbbells, egg-like particles) were characterised by light microscopy in solution, by SEM, and by TEM. X-Ray scattering measurements (WAXS) were used to prove the modification of Calcium Carbonate particles and to calculate the size of Calcium Carbonate and Barium Sulfate nanoparticles.

Kasparova, Pavla

2002-07-01

426

Electromigration Testing of Al-Alloy Films.  

National Technical Information Service (NTIS)

A search for reliability improvement of Al film interconnections has led to the introduction of Al-Alloy films such as Al+Cu, Al+Cu+Si and so on. This report describes the results of an in-depth study of Al, Al+Cu (2 wt % Cu) and Al+Cu+Si (2 wt % Cu + 1% ...

P. B. Ghate

1980-01-01

427

Determination of damage functions for the pitting of AISI type 403 blade alloy and ASTM A470/471 disk alloy  

NASA Astrophysics Data System (ADS)

The prediction of pitting accumulation on turbine blades and disks is of particular importance to predict localized corrosion damages in low pressure (LP) steam turbines. Damage Function Analysis (DFA) and Deterministic Extreme Value Statistics (DEVS) have been employed to predict the pitting damage on AISI Type 403 stainless steel (SS) blade alloy and ASTM A470/471 disk steel in simulated LP steam turbine environments within the phase transition zone. The passivity properties of Type 403 SS and A470/471 steel in the passive regions, including defect type, defect concentration in the barrier film, barrier film thickness, and the steady-state current density, agree with the predictions of the Point Defect Model (PDM) for an n-type semiconductor. Optimization of the PDM based impedance model on the experimental electrochemical impedance data has yielded a set of parameter values that can be used to predict the barrier film growth on Type 403 SS in deaerated borate buffer solution ( pH = 8.2) at ambient temperature. Experimental relationships between the breakdown potential and chloride activity, pH, temperature, and potential scan rate have demonstrated the applicability of the PDM for describing passivity breakdown on Type 403 SS and A470/471 steel. The obtained parameter values were used to calculate the breakdown potential, induction time, and their distributions, via the PDM, which represents the first quantitative characterization of the passivity breakdown behavior on Type 403 SS. Pitting damage functions for Type 403 SS have been experimentally determined for the first time. However, low pit density on A470/471 steel led to insufficient pit numbers on the 1.27 cm2 surface for the effective determination of damage functions. DEVS has been demonstrated by predicting the average maximum pit depth for 750 hours from short-term (24 hours and 240 hours) maximum pit depth data on Type 403 SS in deaerated buffer solution with 0.10 M NaCl at an applied potential of 0.090 VSCE and on A470/471 steel in the solution with 0.028 M NaCl at 0.058 VSCE. To the author's knowledge, the work reported in this dissertation represents the first instance in which DEVS has been used to predict the accumulation of pitting damage on LP steam turbine alloys, thereby heralding a new era in the prediction of corrosion damage in these systems.

Zhang, Yancheng

428

Correlation between Al 2O 3 particles and interface of Al–Al 2O 3 coatings by cold spray  

Microsoft Academic Search

Al–Al2O3 composite coatings with different Al2O3 particle shapes were prepared on Si and Al substrate by cold spray. The powder compositions of metal (Al) and ceramic (Al2O3) having different sizes and agglomerations were varied into ratios of 10:1wt% and 1:1wt%. Al2O3 particles were successfully incorporated into the soft metal matrix of Al. It was found that crater formation between the

Ha Yong Lee; Se Hun Jung; Soo Yong Lee; Young Ho You; Kyung Hyun Ko

2005-01-01

429

Al, Al/C and Al/Si implantations in 6H-SiC  

NASA Astrophysics Data System (ADS)

Multiple-energy Al implantations were performed with and without C or Si coimplantations into 6H-SiC epitaxial layers and bulk substrates at 850°C. The C and Si co-implantations were used as an attempt to improve Al acceptor activation in SiC. The implanted material was annealed at 1500, 1600, and 1650°C for 45 min. The Al implants are thermally stable at all annealing temperatures and Rutherford backscattering via channeling spectra indicated good lattice quality in the annealed Al-implanted material. A net hole concentration of 8 × 1018 cm-3 was measured at room temperature in the layers implanted with Al and annealed at 1600°C. The C or Si co-implantations did not yield improvement in Al acceptor activation. The co-implants resulted in a relatively poor crystal quality due to more lattice damage compared to Al implantation alone. The out-diffusion of Al at the surface is more for 5Si co-implantation compared to Al implant alone, where 5Si means a Si/Al dose ratio of 5.

Rao, Mulpuri V.; Griffiths, Peter; Gardner, Jason; Holland, O. W.; Ghezzo, M.; Kretchmer, J.; Kelner, G.; Freitas, J. A.

1996-01-01

430

Frequently Asked Questions about ALS and the ALS Registry  

MedlinePLUS

... cancer. However, there are no registries or ongoing tracking efforts for ALS in the United States. The ... primary lateral sclerosis will develop problems with nerve cells for both upper and ... part, locations, and phone numbers for more details. Use the “ALS Clinical ...

431

75 FR 62858 - United States, et al.  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF JUSTICE Antitrust Division United States, et al. v. American Express Company, et al.; Proposed Final Judgment and Competitive Impact...District of New York in United States of America, et al. v. American Express Company, et al.,...

2010-10-13

432

76 FR 38700 - United States, et al.  

Federal Register 2010, 2011, 2012, 2013

...DEPARTMENT OF JUSTICE Antitrust Division United States, et al. v. American Express Company, et al.; Public Comments and Response on Proposed...on the proposed Final Judgment in United States, et al. v. American Express Company, et al.,...

2011-07-01

433

Microstructure Evolution and Mechanical Properties of Al\\/Al-Mg\\/Al composite sheet metals  

Microsoft Academic Search

Two different types of aluminum alloys of AA1050 and AA5182 were used to manufacture Al\\/Al-Mg\\/Al composite sheet metals by roll bonding technology at room temperature. The composite sheet metals were annealed at 400 °C and carried out uniaxial tension tests to investigate mechanical properties. Macroscopic mechanical properties are strongly dependent on the volume (or thickness) fraction of two component layers.

Jaehyung Cho; Su-Hyeon Kim; Hyoung-Wook Kim; Cha-Yong Lim; Eun-Young Kim; Shi-Hoon Choi

2011-01-01

434

Analysis of Wear Mechanisms in Low Friction, Nanocomposite AlMgB14-TiB2 Coatings  

SciTech Connect

Recent developments in coating science and technology offer new opportunities to enhance the energy-efficiency and performance of industrial machinery such as hydraulic fluid pumps and motors. The lubricated friction and wear characteristics of two wear-resistant coatings, diamond-like carbon and a nanocomposite material based on AlMgB{sub 14}-50 vol.% TiB{sub 2}, were compared in pin-on-disk tribotests using Mobil DTE-24{trademark} oil as the lubricant. In each case, the pins were fixed 9.53 mm diameter spheres of AISI 52100 steel, the load was 10 N, and the speed 0.5 m/s in all tests. Average steady-state friction coefficient values of 0.10 and 0.08 were measured for the DLC and nanocomposite, respectively. The coatings and their 52100 steel counterfaces were analyzed after the tests by X-ray photoelectron and Auger spectroscopy for evidence of material transfer or tribo-chemical reactions. The low-friction behavior of the boride nanocomposite coating is due to the formation of lubricative boric acid, B(OH){sub 3}. In contrast, the low-friction behavior of the DLC coating is related to the relatively low dielectric constant of the oil-based lubricant, leading to desorption of surface hydrogen from the coating.

Cook, Bruce A [Ames Laboratory; Harringa, J [Ames Laboratory; Anderegg, A [Ames Laboratory; Russell, A M [Iowa State University; Qu, Jun [ORNL; Blau, Peter Julian [ORNL; Higdon, Clifton [Eaton Corporation; Elmoursi, Alaa A [Eaton Corporation

2010-01-01

435

Reliable Au Wire Bonding to Al/Ti/Al Pad  

NASA Astrophysics Data System (ADS)

In this paper, we describe bond degradation and the bondability of an Au wire to a thin-Al/Ti/Al pad. It is found that the pad structure of Al(300 nm)/Ti(300 nm)/Al(1000 nm) is useful for the prevention of bond degradation upon heat treatment at 473 K for 3.6 Ms. Use of the pad necessitated an annealing temperature of at least 723 K, because of its lower initial bond resistance. With heat treatment after thermosonic ball bonding, the bond resistance is almost invariable and the bond shear strength does not decrease. The life of the bond between the Au wire and the pad is extended with thickening of the Ti layer.

Ueno, Hiroshi

1993-05-01

436

AlN/Fe/AlN nanostructures for magnetooptic magnetometry  

NASA Astrophysics Data System (ADS)

AlN/Fe/AlN/Cu nanostructures with ultrathin Fe grown by sputtering on Si substrates are evaluated as probes for magnetooptical (MO) mapping of weak currents. They are considered for a laser wavelength of ? = 410 nm (3.02 eV) and operate at oblique light incidence angles, ?(0), to enable detection of both in-plane and out-of-plane magnetization. Their performance is evaluated in terms of MO reflected wave electric field amplitudes. The maximal MO amplitudes in AlN/Fe/AlN/Cu are achieved by a proper choice of layer thicknesses. The nanostructures were characterized by MO polar Kerr effect at ?(0) ? 5° and longitudinal Kerr effect spectra (?(0) = 45°) at photon energies between 1 and 5 eV. The nominal profiles were refined using a model-based analysis of the spectra. Closed form analytical expressions are provided, which are useful in the search for maximal MO amplitudes.

Lišková-Jakubisová, E.; VišÅovský, Š.; Široký, P.; Hrabovský, D.; Pištora, J.; Harward, I.; Celinski, Z.

2014-05-01

437

Characterization of machining of AISI 1045 steel over a wide range of cutting speeds. Part 2: evaluation of flow stress models and interface friction distribution schemes  

Microsoft Academic Search

To ensure that the simulation of the orthogonal metal-cutting process yields accurate results, the material and frictional behaviours during simulation have to be defined accurately. Flow stress models are used extensively in the simulations of deformation processes occurring at high strains, strain rates, and temperatures. In this work, the Johnson-Cook, Maekawa et al., Oxley, El-Magd et al., and Zerilli-Armstrong flow

S A Iqbal; P T Mativenga; M A Sheikh

2007-01-01

438

Dry Sliding Wear Behavior of Ti-6.5Al-3.5Mo-1.5Zr-0.3Si Alloy  

NASA Astrophysics Data System (ADS)

Dry sliding wear tests were performed for Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy against AISI 52100 steel under the loads of 50 to 250 N at 298 K to 873 K (25 °C to 600 °C). The wear behavior of the alloy varied with the change of test conditions. More or less tribo-oxides TiO2 and Fe2O3 formed on worn surfaces under various conditions. At lower temperature [298 K to 473 K (25 °C to 200 °C)], less and scattered tribo-oxide layers did not show wear-reduced effect. As more number of and continuous tribo-oxide layers appeared at higher temperatures [773 K to 873 K (500 °C to 600 °C)], the wear rate would be substantially reduced. It can be suggested that Ti-6.5Al-3.5Mo-1.5Zr-0.3Si alloy possessed excellent wear resistance at 773 K to 873 K (500 °C to 600 °C). The wear-reduced effect of tribo-oxides seemed to depend on the appearance of Fe2O3 and the amount of tribo-oxides.

Wang, L.; Zhang, Q. Y.; Li, X. X.; Cui, X. H.; Wang, S. Q.

2014-04-01

439

Reply to Gopalswamy et al.  

NASA Technical Reports Server (NTRS)

The comment of Gopalswamy et al. (thereafter GMY) relates to a letter discussing coronal mass ejections (CMEs), interplanetary ejecta and geomagnetic storms. GMY contend that Cane et al. incorrectly identified ejecta (interplanetary CMEs) and hypothesize that this is because Cane et al. fail to understand how to separate ejecta from "shock sheaths" when interpreting solar wind and energetic particle data sets. They (GMY) are wrong be cause the relevant section of the paper was concerned with the propagation time to 1 AU of any potentially geoeffective structures caused by CMEs, i.e. upstream compression regions with or without shocks, or ejecta. In other words, the travel times used by Cane et al. were purposefully and deliberately distinct from ejecta travel times (except for those slow ejecta, approx. 30% of their events, which generated no upstream features), and no error in identification was involved. The confusion of GMY stems from the description did not characterize the observations sufficiently clearly.

Cane, H. V.; Richardson, I. G.

2003-01-01

440

Comparison of one and two-neutron transfer near the coulomb barrier for the 27 Al( 18 O, 16 O) 29 Al, 27 Al( 18 0, 17 O) 28 Al and 27 Al( 13 C, 12 C) 28 Al reactions  

Microsoft Academic Search

Total reaction cross sections for the transfer reactions27Al(18O,16O)29Al,27Al(18O,17O)28Al and27Al(13C,12C)28Al are reported for center-of-mass energies between 13 and 20 MeV for18O projectiles and between 11 and 17.5 MeV for13C projectiles. The reaction products,29Al and28Al, beta decay to29Si and28Si, respectively, and the subsequent? decays of29Si and28Si were measured. Due to the relatively long beta decay half lives, data were taken in a

S. A. Schiller; J. S. Eck

1975-01-01

441

Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s)  

NASA Technical Reports Server (NTRS)

In an effort to better determine the thermodynamic properties of Al(g) and Al2O(g). the vapor in equilibrium with Al(l)+ZrO2(s) was compared to the vapor in equilibrium with Al(l)+Al2O3(s) over temperature range 1197-to-1509K. The comparison was made directly by Knudsen effusion-cell mass spectrometry with an instrument configured for a multiple effusion-cell vapor source (multi-cell KEMS). Second law enthalpies of vaporization of Al(g) and Al2O(g) together with activity measurements show that Al(l)+ZrO2(s) is thermodynamically equivalent to Al(l)+Al2O3(s), indicating Al(l) remained pure and Al2O3(s) was present in the ZrO2-cell. Subsequent observation of the Al(l)/ZrO2 and vapor/ZrO2 interfaces revealed a thin Al2O3-layer had formed, separating the ZrO2-cell from Al(l) and Al(g)+Al2O(g), effectively transforming it into an Al2O3 effusion-cell. This behavior agrees with recent observations made for Beta-NiAl(Pt) alloys measured in ZrO2 effusion-cell.

Copland, Evan

2004-01-01

442

High Density Sliding at Ta/Al and Al/Al Interfaces  

SciTech Connect

We present 3D-nonequilibrium molecular dynamics results for the velocity dependence of the frictional force at smooth sliding interfaces for Ta and Al single crystals. For Ta/Al we consider Al(100)/Ta(100) and Al(111)/Ta(110) interfaces sliding along [001] and [11(bar sign)0]fcc /[001]bcc respectively. These are compared with Al(111)/Al(100) interfaces at the same loads, corresponding to a pressure of 15 GPa. Both interfacial pairs show similar behavior in the velocity dependence of the frictional force: a low velocity regime with an increasing frictional force followed by a strain induced transformation regime at velocities above approximately 1/10 the transverse sound speed, followed by a fluidized interface at high velocities. For both interfacial pairs, the high velocity dependence of the frictional force exhibits power law behavior, Ft {proportional_to} v-{beta} with {beta}=3/4. We discuss the structural changes that influence dissipation in each of these regimes.

Hammerberg, J. E.; Germann, T. C. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Ravelo, R. [Los Alamos National Laboratory, Los Alamos, NM 87545 (United States); Physics Dept., University of Texas -- El Paso, El Paso, TX 79968-0515 (United States); Materials Research Institute, University of Texas - El Paso, El Paso, TX 79968-0515 (United States)

2006-07-28

443

Neuroproteomics: an insight into ALS.  

PubMed

Amyotrophic lateral sclerosis (ALS) is a fatal neurodegenerative disease of unknown aetiology. Diagnosis is made through physical examination, electrophysiological findings, and by excluding other conditions. There is not a single biomarker that concludes the diagnosis. The aim of this study was to investigate differentially expressed proteins in cerebrospinal fluid (CSF) of ALS patients compared to control subjects, with the purpose to identify a panel of possible biomarkers for the disease. The differentially expressed spots/proteins were submitted to two-dimensional (2D) electrophoresis and recognized with matrix-assisted laser desorption/ionization-time of flight (MALDI-TOF) mass spectrometry. Parkin-like and many iron and zinc binding were some of the proteins found in ALS CSF. Parkin is a ligase involved in ubiquitin-proteasome pathway and mutations in the parkin gene are the most common cause of recessive familial Parkinson's disease. Iron and zinc are involved with many important metabolic processes and are related to neurodegenerative disease. Common features of ALS comprise failure of the ubiquitin-proteasome system and increased levels of metal ions in the brain. Therefore, the identification of these proteins can be a significant step in ALS research. These and other identified proteins are discussed in this study. PMID:23146297

Mendonça, D M F; Pizzati, L; Mostacada, K; de S Martins, S C; Higashi, R; Ayres Sá, L; Moura Neto, V; Chimelli, L; Martinez, A M B

2012-12-01

444

Interaction of Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC\\/Al discontinuously reinforced metal matrix composites  

Microsoft Academic Search

Interactions between Al-Si, Al-Ge, and Zn-Al eutectic alloys with SiC whisker-reinforced aluminium metal matrix composites were studied as a function of temperature above the eutectic melting temperature. Penetration extended several millimetres into the composite for the Al-Si and Al-Ge alloys but was restricted to a thin surface layer (50 µm) for the Zn-Al alloy. The extent of the penetration zone

W. C. Moshier; J. S. Ahearn; D. C. Cooke

1987-01-01

445

ALS - A unique design approach  

NASA Astrophysics Data System (ADS)

An advanced launch system (ALS), which is intended to be flexible and to deliver a wide range of payloads at a reduced cost, is discussed. The ALS concept also features total quality management, modular subsystems, standardized interfaces, standardized missions, and off-line payload encapsulation. The technological improvements include manufacturing of dry structures, use of composite materials, adaptive guidance and control systems, and laser-initiated radar systems. The operational improvements range from paperless management, to rocket engine leak detection devices and automated ground operations.

Chamberlain, Roger A.

1990-09-01

446

Al-Biruni's mechanical calendar.  

NASA Astrophysics Data System (ADS)

This paper is concerned with a mechanical calendar described by the great scientist al-Biruni, who died in 440/1048. The description occurs in a book devoted to the construction of various types of astrolabe and related instruments. The Arabic text presented in this paper was prepared from three manuscripts. This is preceded by a brief introduction which gives a sketch of the life and works of al-Biruni together with information about the provenance and contents of the three manuscripts. The text is followed by an English translation and the paper concludes with a technical commentary.

Hill, D. R.

447

Proteccion de aceros al carbono en plantas G.S. (Girldler sulphide): Pte. 7. Efectos de la exposicion al medio ambiente de las capas protectoras de sulfuros y posterior tratamiento en condiciones de planta. (Carbon steel protection in G.S. (Girldler sulphide) plants: Pt. 7. Environment exposure effects on iron sulphide scales and subsequent treatment in plant conditions).  

National Technical Information Service (NTIS)

In order to protect carbon steel towers and piping of a GS experimental heavy water plant against corrosion produced by the action of aqueous solutions of hydrogen sulphide, a method, elsewhere published, was developed. Carbon steel exposed to saturated a...

O. Lires C. Delfino E. Rojo

1989-01-01

448

Andalusian astronomy: al-Zij al-Muqtabis of Ibn al-Kammâd.  

NASA Astrophysics Data System (ADS)

In the twelfth century the Arabic astronomer Ibn al-Kammâd, living in Islamic Spain, composed three sets of astronomical tables, called "zijes". The zijes were largely based on the work of predecessors, going back to Ptolemy on the one hand, and Hindu astronomers on the other. None of his zijes survived in the original Arabic, but a Latin manuscript contains a translation of an apparently complete zij, the "al-Zij al-Muqtabis". This paper examines the body of astronomical knowledge contained in this zij. Specifically, it is shown that one can gain valuable information on the solar theory of the Islamic astronomers from this translation. Furthermore, the theory of lunar and solar eclipses in the work is analyzed, and tables of mean planetary and solar motions are discussed. In addition, tables for the motion of the vernal equinox, star tables, and several topics of Islamic spherical astronomy are examined.

Chabás, J.; Goldstein, B. R.

1994-12-01

449

Glutamate Receptor Aptamers and ALS.  

National Technical Information Service (NTIS)

Excitotoxicity is one of the leading causes for amyotrophic lateral sclerosis (ALS). Our goal was to develop a novel class of powerful aptamer- based, anti-excitotoxic inhibitors against GluR2Qflip, a key AMPA receptor subunit that controls the calcium pe...

L. Niu

2009-01-01

450

AL Amyloidosis and Agent Orange  

MedlinePLUS

... with Agent Orange » AL Amyloidosis and Agent Orange Public Health Public Health Public Health Home Military Exposures Military Exposures Home 4 Ways ... Publications & Reports About Us About the Office of Public Health Post-Deployment Health Clinical Public Health About Clinical ...

451

Dynamic Modeling of ALS Systems  

NASA Technical Reports Server (NTRS)

The purpose of dynamic modeling and simulation of Advanced Life Support (ALS) systems is to help design them. Static steady state systems analysis provides basic information and is necessary to guide dynamic modeling, but static analysis is not sufficient to design and compare systems. ALS systems must respond to external input variations and internal off-nominal behavior. Buffer sizing, resupply scheduling, failure response, and control system design are aspects of dynamic system design. We develop two dynamic mass flow models and use them in simulations to evaluate systems issues, optimize designs, and make system design trades. One model is of nitrogen leakage in the space station, the other is of a waste processor failure in a regenerative life support system. Most systems analyses are concerned with optimizing the cost/benefit of a system at its nominal steady-state operating point. ALS analysis must go beyond the static steady state to include dynamic system design. All life support systems exhibit behavior that varies over time. ALS systems must respond to equipment operating cycles, repair schedules, and occasional off-nominal behavior or malfunctions. Biological components, such as bioreactors, composters, and food plant growth chambers, usually have operating cycles or other complex time behavior. Buffer sizes, material stocks, and resupply rates determine dynamic system behavior and directly affect system mass and cost. Dynamic simulation is needed to avoid the extremes of costly over-design of buffers and material reserves or system failure due to insufficient buffers and lack of stored material.

Jones, Harry

2002-01-01

452

Sobrevivir al cáncer: comer bien  

Cancer.gov

Sobrevivir al cáncer: comer bien Por el Instituto Nacional del Cáncer Bethesda, MD. - Más de 13 millones de personas que viven en Estados Unidos han recibido un diagnóstico de cáncer. Muchas de las personas que han tenido cáncer quieren seguir una

453

The structure and mechanical properties of Fe 3Al–30 vol.% Al 2O 3 nanocomposite  

Microsoft Academic Search

Fe3Al–30vol.% Al2O3 nanocomposite powder was fabricated via two routes. The first route involved the ball milling of Fe2O3–Al–Fe powder mixtures to produce in situ Al2O3 nanoparticles in Fe3Al matrix via mechanochemical reaction of Fe2O3 and Al. In the second route, Fe3Al–Al2O3 nanocomposite was prepared by ex situ addition of Al2O3 nanopowder to Fe–Al powder mixture followed by ball milling. The

M. Khodaei; M. H. Enayati; F. Karimzadeh

2009-01-01

454

Wear testing under high load conditionsThe effect of ``anti-scuff'' additions to AISI 3135, 52100 and 9310 steels introduced by ion implantation and ion beam mixing  

NASA Astrophysics Data System (ADS)

There is a need to eliminate the sudden onset of severe adhesive wear ("scuffing") in high performance hardened steels (e.g. AISI 9310) under arduous load conditions. We have investigated the friction and wear behavior of three ion implanted and ion beam mixed steels under simulated scuffing conditions using a Falex friction and wear tester. This machine enabled tests to be carried out at a load of 700 lb (318 kg), corresponding to a mean contact pressure of approximately 20 000 psi (i.e., 1×10 8 N/m 2) which was sufficient to induce scuffing. A series of lower load tests at 200 lb (91 kg) load (5.2 × 10 7 N/m 2) enabled the longer term wear performance of various ion/substrate combinations to be measured. The frictional force experienced during wear testing was used to assess the degree of scuffing, and the amount of material worn away was measured on the Falex tester or by subsequent weight loss determinations, depending on the type of test. The following ions were implanted: C +, N +, P +, Ti +, Cr +, Mo +, and Ta +, chosen in order to evaluate the effects of intermetallic additions (C, N, P), alloys elements (Ti, Cr), and anti-scuff elements (Mo, Ta). In addition some thin ( ˜1000 Å) vacuum evaporated layers of Si, V, Ni, Nb, Sn, Mo, Ta and W were prepared, and in some cases intermixed with N + ions at a fluence of typically 2×10 17/cm 2, to compare with the effects of ion implantation. Under the low load conditions the wear rate of AISI 3135 steel (1.5% Ni, 0.65% Cr alloy tool steel) was found to be reduced by a factor 3 as a result of N + implantation under low load, in agreement with previous work reported elsewhere, whereas other ions gave inconclusive results. The 52100 steel (a through-hardened martensitic bearing steel) showed marked improvements after Ti + implantation, revealing a sensitivity to fluence which correlated with known dry sliding behaviour of this steel modified by titanium implantations. Ta + and Mo + implantations into 9310 steel (a case-hardened gear steel with 3.0% Ni, 1.4% Cr and 0.55% Mn) reduced the wear rate (in ?g per second) under the low load parameters from 4.2 to 0.15 and 0.26 respectively. Under simulated scuffing, Ta + was effective whereas Mo + was not. SEM examination of the implanted AISI-9310 steel wear pins tested to 200 lb (91 kg) showed extensive smoothing in the implanted worn zones, implying a different wear process. On all the steels, mixed overlayers showed improved friction and wear behavior compared to unmixed layers. The results are discussed in terms of the probable influence of the various added elements on the metallurgical wear mechanisms of the respective steels.

Hartley, N. E. W.; Hirvonen, J. K.

1983-05-01

455

Identification of Candida albicans ALS2 and ALS4 and Localization of Als Proteins to the Fungal Cell Surface  

PubMed Central

Additional genes in the growing ALS family of Candida albicans were isolated by PCR screening of a genomic fosmid library with primers designed from the consensus tandem-repeat sequence of ALS1. This procedure yielded fosmids encoding ALS2 and ALS4. ALS2 and ALS4 conformed to the three-domain structure of ALS genes, which consists of a central domain of tandemly repeated copies of a 108-bp motif, an upstream domain of highly conserved sequences, and a domain of divergent sequences 3? of the tandem repeats. Alignment of five predicted Als protein sequences indicated conservation of N- and C-terminal hydrophobic regions which have the hallmarks of secretory signal sequences and glycosylphosphatidylinositol addition sites, respectively. Heterologous expression of an N-terminal fragment of Als1p in Saccharomyces cerevisiae demonstrated function of the putative signal sequence with cleavage following Ala17. This signal sequence cleavage site was conserved in the four other Als proteins analyzed, suggesting identical processing of each protein. Primary-structure features of the five Als proteins suggested a cell-surface localization, which was confirmed by indirect immunofluorescence with an anti-Als antiserum. Staining was observed on mother yeasts and germ tubes, although the intensity of staining on the mother yeast decreased with elongation of the germ tube. Similar to other ALS genes, ALS2 and ALS4 were differentially regulated. ALS4 expression was correlated with the growth phase of the culture; ALS2 expression was not observed under many different in vitro growth conditions. The data presented here demonstrate that ALS genes encode cell-surface proteins and support the conclusion that the size and number of Als proteins on the C. albicans cell surface vary with strain and growth conditions.

Hoyer, L. L.; Payne, T. L.; Hecht, J. E.

1998-01-01

456

AlSb/InAs/AlSb quantum wells  

NASA Astrophysics Data System (ADS)

Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

Kroemer, Herbert

1990-07-01

457

AlSb/InAs/AlSb quantum wells  

NASA Technical Reports Server (NTRS)

Researchers studied the InAs/AlSb system recently, obtaining 12nm wide quantum wells with room temperature mobilities up to 28,000 cm(exp 2)/V center dot S and low-temperature mobilities up to 325,000 cm(exp 2)/V center dot S, both at high electron sheet concentrations in the 10(exp 12)/cm(exp 2) range (corresponding to volume concentrations in the 10(exp 18)/cm(exp 2) range). These wells were not intentionally doped; the combination of high carrier concentrations and high mobilities suggest that the electrons are due to not-intentional modulation doping by an unknown donor in the AlSb barriers, presumably a stoichiometric defect, like an antisite donor. Inasmuch as not intentionally doped bulk AlSb is semi-insulating, the donor must be a deep one, being ionized only by draining into the even deeper InAs quantum well. The excellent transport properties are confirmed by other observations, like excellent quantum Hall effect data, and the successful use of the quantum wells as superconductive weak links between Nb electrodes, with unprecendentedly high critical current densities. The system is promising for future field effect transistors (FETs), but many processing problems must first be solved. Although the researchers have achieved FETs, the results so far have not been competitive with GaAs FETs.

Kroemer, Herbert

1990-01-01

458

Al-Anon and recovery.  

PubMed

The history of Al-Anon and its current demographics are reviewed. In order to understand 12-step recovery and psychotherapy for family members of alcoholics, the concept of codependence is defined with a set of diagnostic criteria consistent with the DSM-III-R definition of personality traits and disorders. At the core of codependence are denial and an unrealistic relationship to willpower. The therapeutic implications of considering codependence as a personality disorder are explored, as are the characteristics that make codependence unique among personality disorders: the central role of denial and the existence of a self-help organization to facilitate recovery. The dynamics of working the 12 steps on codependent characteristics are outlined. A synergistic relationship between psychotherapy and the 12 steps is described. Special attention is given the emergence of Al-Anon adult children of alcoholic meetings, and the future of codependence is discussed. PMID:2648500

Cermak, T L

1989-01-01

459

First-principles calculations on Al/AlB 2 interfaces  

NASA Astrophysics Data System (ADS)

The AlB 2 (1 1 1) surfaces and Al (1 1 1)/AlB 2 (0 0 0 1) interface were studied by first-principles calculations to clarify the heterogeneous nucleation potential of ?-Al grains on AlB 2 particles in purity aluminium and hypoeutectic Al-Si alloys. It is demonstrated that the AlB 2 (0 0 0 1) surface models with more than nine atomic layers exhibit bulk-like interior, wherein the interlayer relaxations localized within the top three layers are well converged. The outmost layer of AlB 2 free surface having a preference of metal atom termination is evidenced by surface energy calculations. With Al atoms continuing the natural stacking sequence of bulk AlB 2, Al-Al metallic bonds are formed across interface during the combination of Al atoms with Al-terminated AlB 2 surface. The calculated interfacial energy of the Al/AlB 2 interface is much larger than that between the ?-Al and aluminium melts, elucidating the poor nucleation potency of ?-Al grains on AlB 2 particles from thermodynamic considerations.

Han, Y. F.; Dai, Y. B.; Wang, J.; Shu, D.; Sun, B. D.

2011-06-01

460

TiN/Al2O3/TiAlON Composite.  

National Technical Information Service (NTIS)

The present invention pertains to novel improved density ceramic composites of TiN/Al2O3/TiAlON in which there is no spinel and no AlN, but alpha-alumina, titanium nitride, and titanium aluminum oxynitride. In general, the improved density TiN/Al2O3/TiAlO...

K. Han

1990-01-01

461

[Coagulation behavior of Al13 species].  

PubMed

Coagulation behavior of Al13 species was examined in synthetic water with high alkalinity and high humic acid concentration from viewpoint of the transformation of Al hydrolysis products during the coagulation process. The results indicated that coagulation efficiency of Al coagulants positively correlated with the content of Al13 in the coagulation process. Aluminum chloride (AlCl3) was more effective than polyaluminum chloride (PACI) in removing turbidity and dissolved organic matter in the synthetic water because AlCl3 could not only generate Al13 species but also function as pH control agent in the coagulation process. During coagulation process pH control can improve coagulation process through regulating Al speciation, and AlCl3 benefited most from pH control. PMID:17304842

Hu, Cheng-zhi; Liu, Hui-juan; Qu, Jiu-hui

2006-12-01

462

Tensile Behavior of Al2O3/FeAl + B and Al2O3/FeCrAlY Composites  

NASA Technical Reports Server (NTRS)

The feasibility of Al2O3/FeAl + B and Al2O3/FeCrAlY composites for high-temperature applications was assessed. The major emphasis was on tensile behavior of both the monolithics and composites from 298 to 1100 K. However, the study also included determining the chemical compatibility of the composites, measuring the interfacial shear strengths, and investigating the effect of processing on the strength of the single-crystal Al2O3 fibers. The interfacial shear strengths were low for Al203/FeAl + B and moderate to high for Al203/FeCrAlY. The difference in interfacial bond strengths between the two systems affected the tensile behavior of the composites. The strength of the Al203 fiber was significantly degraded after composite processing for both composite systems and resulted in poor composite tensile properties. The ultimate tensile strength (UTS) values of the composites could generally be predicted with either rule of mixtures (ROM) calculations or existing models when using the strength of the etched-out fiber. The Al2O3/FeAl + B composite system was determined to be unfeasible due to poor interfacial shear strengths and a large mismatch in coefficient of thermal expansion (CTE). Development of the Al2O3/FeCrAlY system would require an effective diffusion barrier to minimize the fiber strength degradation during processing and elevated temperature service.

Draper, S. L.; Eldridge, J. I.; Aiken, B. J. M.

1995-01-01

463

Mg isotopic heterogeneity, Al-Mg isochrons, and canonical 26Al/27Al in the early solar system  

NASA Astrophysics Data System (ADS)

Abstract-There is variability in the Mg isotopic composition that is a reflection of the widespread heterogeneity in the isotopic composition of the elements in the solar system at approximately 100 ppm. Measurements on a single calcium-aluminum-rich inclusion (CAI) gave a good correlation of 26Mg/24Mg with 27<span class="hlt">Al</span>/24Mg, yielding an isochron corresponding to an initial (26<span class="hlt">Al</span>/27<span class="hlt">Al</span>)o = (5.27 ± 0.18) × 10-5 and an initial (26Mg/24Mg)o = -0.127 ± 0.032‰ relative to the standard. This isochron is parallel to that obtained by <link href="#b41 #b42">Jacobsen et <span class="hlt">al</span>. (2008), but is distinctively offset. This demonstrates that there are different initial Mg isotopic compositions in different samples with the same 26<span class="hlt">Al</span>/27<span class="hlt">Al</span>. No inference about uniformity/heterogeneity of 26<span class="hlt">Al</span>/27<span class="hlt">Al</span> on a macro scale can be based on the initial (26Mg/24Mg)o values. Different values of 26<span class="hlt">Al</span>/27<span class="hlt">Al</span> for samples representing the same point in time would prove heterogeneity of 26<span class="hlt">Al</span>/27<span class="hlt">Al</span>. The important issue is whether the bulk solar inventory of 26<span class="hlt">Al</span>/27<span class="hlt">Al</span> was approximately 5 × 10-5 at some point in the early solar system. We discuss ultra refractory phases of solar type oxygen isotope composition with 26<span class="hlt">Al</span>/27<span class="hlt">Al</span> from approximately 5 × 10-5 to below 0.2 × 10-5. We argue that the real issues are: intrinsic heterogeneity in the parent cloud; mechanism and timing for the later production of 16O-poor material; and the relationship to earlier formed 16O-rich material in the disk. 26<span class="hlt">Al</span>-free refractories can be produced at a later time by late infall, if there is an adequate heat source, or from original heterogeneities in the placental molecular cloud from which the solar system formed.</p> <div class="credits"> <p class="dwt_author">Wasserburg, G. J.; Wimpenny, Josh; Yin, Qing-Zhu</p> <p class="dwt_publisher"></p> <p class="publishDate">2012-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">464</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2014ApPhA.tmp..246S"> <span id="translatedtitle">Plasmonics properties of trimetallic <span class="hlt">Al@Al</span>2O3@Ag@Au and <span class="hlt">Al@Al</span>2O3@AuAg nanostructures</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Bimetallic and trimetallic nanoparticles have attracted significant attention in recent times due to their enhanced electrochemical and catalytic properties compared to monometallic nanoparticles. The numerical calculations using Mie theory has been carried out for three-layered metal nanoshell dielectric-metal-metal (DMM) system consisting of a particle with a dielectric core (<span class="hlt">Al@Al</span>2O3), a middle metal Ag (Au) layer and an outer metal Au (Ag) shell. The results have been interpreted using plasmon hybridization theory. We have also prepared <span class="hlt">Al@Al</span>2O3@Ag@Au and <span class="hlt">Al@Al</span>2O3@AgAu triple-layered core-shell or alloy nanostructure by two-step laser ablation method and compared with calculated results. The synthesis involves temporal separations of <span class="hlt">Al</span>, Ag, and Au deposition for step-by-step formation of triple-layered core-shell structure. To form <span class="hlt">Al</span>@Ag nanoparticles, we ablated silver for 40 min in aluminium nanoparticle colloidal solution. As aluminium oxidizes easily in water to form alumina, the resulting structure is core-shell <span class="hlt">Al@Al</span>2O3. The <span class="hlt">Al@Al</span>2O3 particle acts as a seed for the incoming energetic silver particles for multilayered <span class="hlt">Al@Al</span>2O3@Ag nanoparticles is formed. The silver target was then replaced by gold target and ablation was carried out for different ablation time using different laser energy for generation of <span class="hlt">Al@Al</span>2O3@Ag@Au core-shell or <span class="hlt">Al@Al</span>2O3@AgAu alloy. The formation of core-shell and alloy nanostructure was confirmed by UV-visible spectroscopy. The absorption spectra show shift in plasmon resonance peak of silver to gold in the range 400-520 nm with increasing ablation time suggesting formation of Ag-Au alloy in the presence of alumina particles in the solution.</p> <div class="credits"> <p class="dwt_author">Singh, Rina; Soni, R. K.</p> <p class="dwt_publisher"></p> <p class="publishDate">2014-05-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">465</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ncbi.nlm.nih.gov/pubmed/14645389"> <span id="translatedtitle">Form of <span class="hlt">Al</span> changes with <span class="hlt">Al</span> concentration in leaves of buckwheat.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?DB=pubmed">PubMed</a></p> <p class="result-summary">Buckwheat (Fagopyrum esculentum Moench. cv. Jianxi) is known as an <span class="hlt">Al</span>-accumulating plant. The process leading to the accumulation of <span class="hlt">Al</span> in the leaves was investigated, focusing on the chemical form of <span class="hlt">Al</span> using 27<span class="hlt">Al</span>-nuclear magnetic resonance. Leaves with different <span class="hlt">Al</span> concentrations were prepared by growing buckwheat on a very acidic soil (Andosol) amended with or without CaCO3 (1 or 3 g x kg-1 soil). When the <span class="hlt">Al</span> concentration of the leaves was lower, only one major signal was observed at a chemical shift of 16.1 ppm, which was assigned to an <span class="hlt">Al</span>-oxalate complex at a 1:3 ratio. However, when the <span class="hlt">Al</span> concentration of the leaves increased to a high level (e.g. 12 g <span class="hlt">Al</span> kg-1), an additional signal at a chemical shift of 11.2 ppm was observed. This signal was assigned to an <span class="hlt">Al</span>-citrate complex at a 1:1 ratio. In the leaf with a high <span class="hlt">Al</span> concentration, both <span class="hlt">Al</span>-oxalate (1:3) and <span class="hlt">Al</span>-citrate (1:1) were detected in marginal and middle parts, while only <span class="hlt">Al</span>-oxalate was detected in the basal part. The oxalate concentration did not differ very much between leaves with low and high <span class="hlt">Al</span> concentrations at the same position, while citrate concentration significantly increased with increasing <span class="hlt">Al</span> concentration when the oxalate/<span class="hlt">Al</span> ratio became lower than 3.0. As the <span class="hlt">Al</span>-citrate complex has been demonstrated to be the form of transport in the xylem, the results suggest that when internal oxalate is enough to form a complex with <span class="hlt">Al</span> at a 3:1 ratio in the leaves with a low <span class="hlt">Al</span> concentration, <span class="hlt">Al</span>-citrate converts to <span class="hlt">Al</span>-oxalate. However, this conversion does not occur in the leaves with a very high <span class="hlt">Al</span> concentration, resulting in the coexistence of both <span class="hlt">Al</span>-oxalate and <span class="hlt">Al</span>-citrate complexes. PMID:14645389</p> <div class="credits"> <p class="dwt_author">Shen, Renfang; Iwashita, Takashi; Ma, Jian Feng</p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">466</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/21608136"> <span id="translatedtitle">Synthesis of <span class="hlt">AlN/Al</span> Polycrystals along with <span class="hlt">Al</span> Nanoparticles Using Thermal Plasma Route</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">This paper for the first time reports the (200) oriented growth of hexagonal Aluminum nitride crystals during synthesis of aluminum nanoparticles in dc transferred arc thermal plasma reactor by gas phase condensation in nitrogen plasma. The structural and morphological study of as synthesized <span class="hlt">Al</span>N crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.</p> <div class="credits"> <p class="dwt_author">Kanhe, Nilesh S.; Nawale, A. B.; Kulkarni, N. V.; Bhoraskar, S. V.; Mathe, V. L. [Department of Physics, University of Pune, Pune 411007 (India); Das, A. K. [Laser and Plasma Technology Division, Bhabha Atomic Research Centre, Trombay, Mumbai, 400085 (India)</p> <p class="dwt_publisher"></p> <p class="publishDate">2011-07-15</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">467</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=19940032245&hterms=powder+metallography&qs=Ntx%3Dmode%2Bmatchall%26Ntk%3DAll%26N%3D0%26No%3D50%26Ntt%3Dpowder%2Bmetallography"> <span id="translatedtitle">Ni<span class="hlt">Al</span>-base composite containing high volume fraction of <span class="hlt">Al</span>N for advanced engines</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary">A particulate reinforced Ni<span class="hlt">Al-Al</span>N composite alloy has a Ni<span class="hlt">Al</span> matrix and greater than about 13 volume percent fine particles of <span class="hlt">Al</span>N within the matrix. The particles preferably have a diameter from about 15 nanometers to about 50 nanometers. The particulate reinforced Ni<span class="hlt">Al-Al</span>N composite alloy may be prepared by cryomilling prealloyed Ni<span class="hlt">Al</span> in liquid nitrogen using grinding media having a diameter of from about 2 to 6 mm at an impeller speed of from about 450 RPM to about 800 RPM. The cryomilling may be done for a duration of from about 4 hours to about 20 hours to obtain a cryomilled powder. The cryomilled powder may be consolidated to form the particulate reinforced Ni<span class="hlt">Al-Al</span>N composite alloy. The particulate reinforced alloy can further include a toughening alloy. The toughening alloy may include NiCr<span class="hlt">Al</span>Y, FeCr<span class="hlt">Al</span>Y, and Fe<span class="hlt">Al</span>.</p> <div class="credits"> <p class="dwt_author">Hebsur, Mohan (inventor); Whittenbeger, John D. (inventor); Lowell, Carl F. (inventor)</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">468</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49428031"> <span id="translatedtitle">Evolution of deformation texture in <span class="hlt">Al\\/Al–Mg\\/Al</span> composite sheets during cold-roll cladding</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary"><span class="hlt">Al\\/Al–Mg\\/Al</span> composite sheets were fabricated by roll cladding to investigate the evolution of deformation texture through the thickness direction. Electron backscatter diffraction (EBSD) was used to analyze the heterogeneity of deformation texture in each component layer of the composite sheets. Finite element analysis (FEA) was conducted to simulate the deformation history in each component layer during roll cladding. The deformation</p> <div class="credits"> <p class="dwt_author">Eun-Young Kim; JaeHyung Cho; Hyoung-Wook Kim; Shi-Hoon Choi</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">469</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40368817"> <span id="translatedtitle">Electrochemical behaviour and corrosion performance of Mg–Li–<span class="hlt">Al</span>–Zn anodes with high <span class="hlt">Al</span> composition</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This study investigated the electrochemical and corrosion performance of Mg–Li–<span class="hlt">Al</span>–Zn anodes with <span class="hlt">Al</span> compositions of ?3 wt.% and ?9 wt.%. Mg–Li–<span class="hlt">Al</span>–Zn alloy with ?9 wt.% <span class="hlt">Al</span> had a relatively negative open-circuit potential and a high discharge voltage in MgCl2 electrolyte, owing to the distribution of numerous <span class="hlt">Al</span>Li particles in the matrix of the alloy. <span class="hlt">Al</span>Li particles were believed to transform</p> <div class="credits"> <p class="dwt_author">M. C. Lin; C. Y. Tsai; J. Y. Uan</p> <p class="dwt_publisher"></p> <p class="publishDate">2009-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">470</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40940053"> <span id="translatedtitle">Microstructures and mechanical properties of Fe 3<span class="hlt">Al</span>-based Fe–<span class="hlt">Al</span>–C alloys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In this paper results on the microstructures and mechanical properties of Fe3<span class="hlt">Al</span>-based Fe–<span class="hlt">Al</span>–C alloys with strengthening precipitates of the perovskite-type ?-phase Fe3<span class="hlt">Al</span>Cx are presented. The alloys are prepared by vacuum induction melting and cast into Cu-moulds. The composition of the Fe3<span class="hlt">Al</span> matrix of the investigated Fe–<span class="hlt">Al</span>–C alloys varies between 23 and 29at.% <span class="hlt">Al</span>. The ternary C-additions range from 1 to</p> <div class="credits"> <p class="dwt_author">A. Schneider; L. Falat; G. Sauthoff; G. Frommeyer</p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">471</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/48342061"> <span id="translatedtitle">Werbung <span class="hlt">als</span> Verhaltensvorbild für Mitarbeiter</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">\\u000a Seit der Kampagne „FedEx. Whatever it takes.“ gilt das Logistikunternehmen FedEx <span class="hlt">als</span> Trendsetter in Sachen Werbung. Mit der\\u000a Kampagne ist es FedEx gelungen, seine tendenziell „farblose“ Dienstleistung emotional aufzuladen und für den Kunden greifbar\\u000a zu machen. Zudem konnte die Bekanntheit der Marke gesteigert werden. FedEx schaffte noch im Erscheinungsjahr der Kampagne\\u000a erstmals den Sprung in das Interbrand-Ranking der einhundert wertvollsten</p> <div class="credits"> <p class="dwt_author">Sven Henkel; Torsten Tomczak; Wolfgang Jenewein</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">472</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/49256081"> <span id="translatedtitle">The coarsening behavior of duplex <span class="hlt">Al</span> 2O 3\\/Ni<span class="hlt">Al</span> 2O 4 composites</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">In The Present Study, The Grain Growth Behavior Of <span class="hlt">Al</span>2O3\\/Nial2O4 Composite Is Compared With That Of <span class="hlt">Al</span>2O3 And Of Ni<span class="hlt">Al</span>2O4. Duplex <span class="hlt">Al</span>2O3\\/Ni<span class="hlt">Al</span>2O4 composite shows strong resistance to coarsening. The activation energy for the grain growth of monolithic <span class="hlt">Al</span>2O 3 is the same as that of <span class="hlt">Al</span>2O3 in composite. However, the activation energy for the grain growth of Ni<span class="hlt">Al</span>2O4 is changed</p> <div class="credits"> <p class="dwt_author">W. H. Tuan; M. C. Lin; W. H. Tzing</p> <p class="dwt_publisher"></p> <p class="publishDate">1997-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">473</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40987596"> <span id="translatedtitle">Growth stage kinetics in the synthesis of <span class="hlt">Al</span> 2O 3\\/<span class="hlt">Al</span> composites by directed oxidation of <span class="hlt">Al</span>-Mg and <span class="hlt">Al</span>-Mg-Si alloys</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">Although synthesis of ceramic matrix composites by the directed oxidation process offers significant advantages over traditional composite processing routes, the scientific basis for the process is not fully understood. This paper is addressed to understanding the mechanism of composite growth from <span class="hlt">Al</span>-Mg and <span class="hlt">Al</span>-Mg-Si alloys theoretically and experimentally. Analysis of the oxidation kinetics of <span class="hlt">Al</span>-Mg and <span class="hlt">Al</span>-Mg-Si alloys for various</p> <div class="credits"> <p class="dwt_author">H. Venugopalan; T. DebRoy</p> <p class="dwt_publisher"></p> <p class="publishDate">1996-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">474</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE94016877"> <span id="translatedtitle">Nonstoichiometry of <span class="hlt">Al</span>-Zr intermetallic phases.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">Nonstoichiometry of metastable cubic (beta)(prime) and equilibrium tetragonal (beta) <span class="hlt">Al</span>-Zr intermetallic phases of the nominal composition <span class="hlt">Al</span>(sub 3)Zr in <span class="hlt">Al</span>-rich alloys has been extensively studied. It is proposed that the ''dark contrast'' of (beta)(prim...</p> <div class="credits"> <p class="dwt_author">V. Radmilovic G. Thomas</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">475</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/servlets/purl/10174408"> <span id="translatedtitle">Nonstoichiometry of <span class="hlt">Al</span>-Zr intermetallic phases</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">Nonstoichiometry of metastable cubic {beta}{prime} and equilibrium tetragonal {beta} <span class="hlt">Al</span>-Zr intermetallic phases of the nominal composition <span class="hlt">Al</span>{sub 3}Zr in <span class="hlt">Al</span>-rich alloys has been extensively studied. It is proposed that the ``dark contrast`` of {beta}{prime} core in {beta}{prime}/{sigma}{prime} complex precipitates, in <span class="hlt">Al</span>-Li-Zr based alloys, is caused by incorporation of <span class="hlt">Al</span> and Li atoms into the {beta}{prime} phase on Zr sublattice sites, forming nonstoichiometric <span class="hlt">Al</span>-Zr intermetallic phases, rather than by Li partitioning only. {beta}{prime} particles contain very small amounts of Zr, approximately 5 at.%, much less than the stoichiometric 25 at.% in the <span class="hlt">Al</span>{sub 3}Zr metastable phase. These particles are, according to simulation of high resolution images, of the <span class="hlt">Al</span>{sub 3}(<span class="hlt">Al</span>{sub 0.4}Li{sub 0.4}Zr{sub 0.2}) type. Nonstoichiometric particles of average composition <span class="hlt">Al</span>{sub 4}Zr and <span class="hlt">Al</span>{sub 6}Zr are observed also in the binary <span class="hlt">Al</span>-Zr alloy, even after annealing for several hours at 600{degree}C.</p> <div class="credits"> <p class="dwt_author">Radmilovic, V.; Thomas, G.</p> <p class="dwt_publisher"></p> <p class="publishDate">1994-06-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">476</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.ntis.gov/search/product.aspx?ABBR=DE99002885"> <span id="translatedtitle">U-<span class="hlt">Al</span> alloy charge makeup equation.</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.ntis.gov/search/index.aspx">National Technical Information Service (NTIS)</a></p> <p class="result-summary">The (sup 235)U content in fuel tubes (g(sup 235)U/ft) is directly proportional to the (sup 235)U concentration (g(sup 235)U/cc) in the U-<span class="hlt">Al</span> core alloy. In order to prepare enriched uranium metal, aluminum, and U-<span class="hlt">Al</span> scrap for U-<span class="hlt">Al</span> production melts, the ove...</p> <div class="credits"> <p class="dwt_author">F. C. Rhode</p> <p class="dwt_publisher"></p> <p class="publishDate">1988-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">477</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/53919357"> <span id="translatedtitle"><span class="hlt">Al</span>-Cr-Nb (Aluminium - Chromium - Niobium)</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">This document is part of Subvolume A1 'Light Metal Systems. Part 1: Selected Systems from Ag-<span class="hlt">Al</span>-Cu to <span class="hlt">Al</span>-Cu-Er' of Volume 11 'Ternary Alloy Systems - Phase Diagrams, Crystallographic and Thermodynamic Data critically evaluated by MSIT®' of Landolt-Börnstein - Group IV Physical Chemistry. It provides the data for the ternary system <span class="hlt">Al</span>-Cr-Nb (Aluminium - Chromium - Niobium).</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2004-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">478</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2010JCrGr.312.2569K"> <span id="translatedtitle">Possibility of <span class="hlt">Al</span>N growth using Li-<span class="hlt">Al</span>-N solvent</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">The possibility of <span class="hlt">Al</span>N growth using Li-<span class="hlt">Al</span>-N solvent was investigated. Based on theoretical prediction, we selected Li 3N as a suitable nitrogen source for <span class="hlt">Al</span>N growth. First, vapor phase epitaxy using Li 3N and <span class="hlt">Al</span> as source materials was performed to confirm the following reaction on the growth surface: Li 3N+<span class="hlt">Al=Al</span>N+3Li. The results suggest that the reaction proceeds to form <span class="hlt">Al</span>N on the substrate under appropriate conditions. Next, <span class="hlt">Al</span>N growth using Li-<span class="hlt">Al</span>-N solvent was carried out. The Li-<span class="hlt">Al</span>-N solvent was prepared by annealing of mixtures composed of Li 3N and <span class="hlt">Al</span>. The results imply that <span class="hlt">Al</span>N was formed under an <span class="hlt">Al</span>-rich condition. Moreover, it was found that Li was swept out from <span class="hlt">Al</span>N grains during growth. The results suggest that <span class="hlt">Al</span>N growth using Li-<span class="hlt">Al</span>-N solvent might be a key technology to obtain an <span class="hlt">Al</span>N crystal boule.</p> <div class="credits"> <p class="dwt_author">Kangawa, Yoshihiro; Kakimoto, Koichi</p> <p class="dwt_publisher"></p> <p class="publishDate">2010-09-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">479</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/20005991"> <span id="translatedtitle">Wear behavior of <span class="hlt">Al-Al</span>{sub 3}Ti composite manufactured by a centrifugal method</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary">The purpose of the present study was to develop a wear-resistant, light <span class="hlt">Al-Al</span>{sub 3}Ti composite material. An <span class="hlt">Al-Al</span>{sub 3}Ti composite specimen was machined from a thick-walled tube of <span class="hlt">Al-Al</span>{sub 3}Ti functionally graded material (FGM) manufactured by the centrifugal method from a commercial ingot of <span class="hlt">Al</span>-5 mass% Ti master alloy. The alloy was heated to a temperature where solid <span class="hlt">Al</span>{sub 3}Ti particles resided in a liquid <span class="hlt">Al</span> matrix, and then the centrifugal method was carried out. <span class="hlt">Al</span>{sub 3}Ti particles in a commercial alloy ingot exist as platelets, and this shape was maintained through the casting. Three kinds of wear specimens were prepared, taking into account the morphology of the <span class="hlt">Al</span>{sub 3}Ti particles in the thick-walled FGM tube; the <span class="hlt">Al</span>{sub 3}Ti particles were arranged with their platelet planes nearly normal to the radial direction as a result of the applied centrifugal force. The wear resistance of the <span class="hlt">Al-Al</span>{sub 3}Ti composite was significantly higher than that of pure <span class="hlt">Al</span>. Wear-resistance anisotropy and dissolution of the <span class="hlt">Al</span>{sub 3}Ti into the <span class="hlt">Al</span> matrix at the near-surface region, around 100 {micro}m in depth, were also observed. The mechanism of the supersaturated-layer formation and the origin of the anisotropic wear resistance are discussed.</p> <div class="credits"> <p class="dwt_author">Watanabe, Yoshimi; Yamanaka, Noboru; Fukui, Yasuyoshi</p> <p class="dwt_publisher"></p> <p class="publishDate">1999-12-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">480</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2013JSSCh.198..330R"> <span id="translatedtitle">Aluminium distribution in ZSM-5 revisited: The role of <span class="hlt">Al-Al</span> interactions</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">We present a theoretical study of the distribution of <span class="hlt">Al</span> atoms in zeolite ZSM-5 with Si/<span class="hlt">Al</span>=47, where we focus on the role of <span class="hlt">Al-Al</span> interactions rather than on the energetics of <span class="hlt">Al</span>/Si substitutions at individual sites. Using interatomic potential methods, we evaluate the energies of the full set of symmetrically independent configurations of <span class="hlt">Al</span> siting in a Si94<span class="hlt">Al</span>2O192 cell. The equilibrium <span class="hlt">Al</span> distribution is determined by the interplay of two factors: the energetics of the <span class="hlt">Al</span>/Si substitution at an individual site, which tends to populate particular T sites (e.g., the T14 site), and the <span class="hlt">Al-Al</span> interaction, which at this Si/<span class="hlt">Al</span> maximises <span class="hlt">Al-Al</span> distances in general agreement with Dempsey's rule. However, it is found that the interaction energy changes approximately as the inverse of the square of the distance between the two <span class="hlt">Al</span> atoms, rather than the inverse of the distance expected if this were merely charge repulsion. Moreover, we find that the anisotropic nature of the framework density plays an important role in determining the magnitude of the interactions, which are not simply dependent on <span class="hlt">Al-Al</span> distances.</p> <div class="credits"> <p class="dwt_author">Ruiz-Salvador, A. Rabdel; Grau-Crespo, Ricardo; Gray, Aileen E.; Lewis, Dewi W.</p> <p class="dwt_publisher"></p> <p class="publishDate">2013-02-01</p> </div> </div> </div> </div> <div id="filter_results_form" class="filter_results_form floatContainer" style="visibility: visible;"> <div style="width:100%" id="PaginatedNavigation" class="paginatedNavigationElement"> <a id="FirstPageLink" onclick='return showDiv("page_1");' href="#" title="First Page"> <img id="FirstPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.first.18x20.png" alt="First Page" /></a> <a id="PreviousPageLink" onclick='return showDiv("page_23");' href="#" title="Previous Page"> <img id="PreviousPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.previous.18x20.png" alt="Previous Page" /></a> <span id="PageLinks" class="pageLinks"> <span> <a onClick='return showDiv("page_1");' href="#">1</a> <a onClick='return showDiv("page_2");' href="#">2</a> <a onClick='return showDiv("page_3");' 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src="http://www.science.gov/scigov/images/icon.next.18x20.png" alt="Next Page" /></a> <a id="LastPageLink" onclick='return showDiv("page_25.0");' href="#" title="Last Page"> <img id="LastPageLinkImage" class="Icon" src="http://www.science.gov/scigov/images/icon.last.18x20.png" alt="Last Page" /></a> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">481</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://ntrs.nasa.gov/search.jsp?R=PIA07216&hterms=Arabic+Arabic+al-+arab+yah&qs=N%3D0%26Ntk%3DAll%26Ntx%3Dmode%2Bmatchall%26Ntt%3DArabic%2B%257C%2B%25D8%25A7%25D9%2584%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%25D8%25A9%2B%257C%2Bal-%25CA%25BBarab%25C4%25AByah%2B%257C%2B%25D8%25B9%25D8%25B1%25D8%25A8%25D9%258A%252F%2526"> <span id="translatedtitle">Opportunity's 'Rub <span class="hlt">al</span> Khali' Panorama</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://ntrs.nasa.gov/search.jsp">NASA Technical Reports Server (NTRS)</a></p> <p class="result-summary"><p/> [figure removed for brevity, see original site] Click on the image for Opportunity's 'Rub <span class="hlt">al</span> Khali' Panorama (QTVR) <p/> This panoramic image, dubbed 'Rub <span class="hlt">al</span> Khali,' was acquired by NASA's Mars Exploration Rover Opportunity on the plains of Meridiani during the period from the rover's 456th to 464th sols on Mars (May 6 to May 14, 2005). Opportunity was about 2 kilometers (1.2 miles) south of 'Endurance Crater' at a place known informally as 'Purgatory Dune.' <p/> The rover was stuck in the dune's deep fine sand for more than a month. 'Rub <span class="hlt">al</span> Khali' (Arabic translation: 'the empty quarter') was chosen as the name for this panorama because it is the name of a similarly barren, desolate part of the Saudi Arabian desert on Earth. <p/> The view spans 360 degrees. It consists of images obtained in 97 individual pointings of the panoramic camera. The camera took images with five camera filters at each pointing. This 22,780-by-6,000-pixel mosaic is an approximately true-color rendering generated using the images acquired through filters admitting light wavelengths of 750, 530, and 480 nanometers. <p/> Lighting varied during the nine sols it took to acquire this panorama, resulting in some small image seams within the mosaic. These seams have been smoothed in sky parts of the mosaic to better simulate the vista that a person would see if able to view it all at the same time on Mars. <p/> Opportunity's tracks leading back to the north (center of the panorama) are a reminder of the rover's long trek from Endurance Crater. The deep ruts dug by Opportunity's wheels as it became stuck in the sand appear in the foreground. The crest and trough of the last ripple the rover crossed before getting stuck is visible in the center. These wind-formed sand features are only about 10 to 15 centimeters (4 to 6 inches) tall. The crest of the actual ripple where the rover got stuck can be seen just to the right of center. The tracks and a few other places on and near ripple crests can be seen in this color image to be dustier than the undisturbed or 'normal' plains soils in Meridiani. Since the time these ruts were made, some of the dust there has been blown away by the wind, reaffirming the dynamic nature of the martian environment, even in this barren, ocean-like desert of sand.</p> <div class="credits"> <p class="dwt_author"></p> <p class="dwt_publisher"></p> <p class="publishDate">2005-01-01</p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">482</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://academic.research.microsoft.com/Publication/40437515"> <span id="translatedtitle">TiN\\/Cr\\/<span class="hlt">Al</span> 2O 3 and TiN\\/<span class="hlt">Al</span> 2O 3 hybrid coatings structure features and properties resulting from combined treatment</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://academic.research.microsoft.com/">Microsoft Academic Search </a></p> <p class="result-summary">New experimental results are presented on the structure and the elemental and phase composition of hybrid coatings, which were deposited on a substrate of <span class="hlt">AISI</span> 321 stainless steel using a combination of plasma-detonation, vacuum-arc and subsequent High-Current Electron Beam (HCEB) treatment. We found that an increase in energy density intensified mass transfer processes and resulted in changes in aluminum oxide</p> <div class="credits"> <p class="dwt_author">A. D. Pogrebnjak; Yu. A. Kravchenko; S. B. Kislitsyn; Sh. M. Ruzimov; F. Noli; P. Misaelides; A. Hatzidimitriou</p> <p class="dwt_publisher"></p> <p class="publishDate">2006-01-01</p> </div> </div> </div> </div> <div class="floatContainer result odd" lang="en"> <div class="resultNumber element">483</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://adsabs.harvard.edu/abs/2009bein.book...29D"> <span id="translatedtitle">Instandhaltungsmanagement <span class="hlt">als</span> Gestaltungsfeld Ganzheitlicher Produktionssysteme</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://adsabs.harvard.edu/abstract_service.html">NASA Astrophysics Data System (ADS)</a></p> <p class="result-summary">Sich kontinuierlich verändernde Rahmenbedingungen, wie beispielsweise eine steigende Variantenvielfalt, verkürzte Produktlebenszyklen sowie Kundenforderungen nach höherer Qualität, kürzeren Lieferzeiten und geringeren Kosten, fordern von produzierenden Unternehmen eine stetige Anpassung der Prozesse, der Organisation und der Strukturen. Seit den 90er Jahren versuchen immer mehr deutsche Unternehmen diesen veränderten Anforderungen mit der Einführung eines Ganzheitlichen Produktionssystems (GPS) zu begegnen. Ganzheitliche Produktionssysteme sind dabei in ihren Grundlagen an das Toyota Produktionssystem angelehnt, vereinigen aber auch weitere Methoden zu einem unternehmensspezifischen Regelwerk. Im Rahmen des langfristigen Trends zu unternehmensindividuellen Produktionssystemen wird sowohl in der Industrie <span class="hlt">als</span> auch in der Forschung intensiv über das Toyota Produktionssystem, Lean Production, Lean Management und Ganzheitliche Produktionssysteme diskutiert, werden Konzepte zu Implementierung und Betrieb erstellt und die Wirtschaftlichkeit untersucht.</p> <div class="credits"> <p class="dwt_author">Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo</p> <p class="dwt_publisher"></p> <p class="publishDate"></p> </div> </div> </div> </div> <div class="floatContainer result " lang="en"> <div class="resultNumber element">484</div> <div class="resultBody element"> <p class="result-title"><a target="resultTitleLink" href="http://science.gov/scigov/link.html?type=RESULT&redirectUrl=http://www.osti.gov/scitech/biblio/282257"> <span id="translatedtitle">Microstructure and properties of <span class="hlt">Al</span>{sub 2}O{sub 3}-<span class="hlt">Al</span>(Si) and <span class="hlt">Al</span>{sub 2}O{sub 3}-<span class="hlt">Al</span>(Si)-Si composites formed by in situ reaction of <span class="hlt">Al</span> with aluminosilicate ceramics</span></a>  </p> <div class="result-meta"> <p class="source"><a target="_blank" id="logoLink" href="http://www.osti.gov/scitech">SciTech Connect</a></p> <p class="result-summary"><span class="hlt">Al</span>{sub 2}O{sub 3}-<span class="hlt">Al</span>(Si) and <span class="hlt">Al</span>{sub 2}O{sub 3}-<span class="hlt">Al</span>(Si)-Si composites have been formed by in situ reaction of molten <span class="hlt">Al</span> with aluminosilicate ceramics. This reactive metal