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1

Aluminum diffusion in Al-implanted AISI 321 stainless steel using accelerator-based characterization techniques  

NASA Astrophysics Data System (ADS)

The aluminum diffusion in near-surface layers of Al-implanted AISI 321 austenitic stainless steel (Fe/Cr18/Ni8/Ti) was studied using ion beam analysis techniques. The implanted samples were investigated at temperatures between 450 degC and 650 degC (treatment times up to 144 h in vacuum and in air). The Al-profiles were determined by the 992keV resonance of the 27Al(p,?)28Si nuclear reaction as well as by 4He+-Rutherford Backscattering Spectrometry (RBS). The experimental diffusion coefficients, obtained during this study using Fick's second law, were compared with corresponding literature concerning the aluminum diffusion in other relevant metallic materials. The determination of the depth profiles contributes to the interpretation of the high temperature oxidation behavior of Al-implanted stainless steel surfaces.

Noli, F.; Misaelides, P.; Bethge, K.

1998-04-01

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

Reciprocating friction and wear behavior of Ti 3AlC 2 and Ti 3AlC 2\\/Al 2O 3 composites against AISI52100 bearing steel  

Microsoft Academic Search

In this work, the dry sliding friction and wear properties of Ti3AlC2 and Ti3AlC2\\/Al2O3 composites against AISI52100 steel ball were investigated using a reciprocating ball on flat configuration under different normal loads. The results indicated that the friction\\/wear processes of both Ti3AlC2 and the composites against AISI52100 steel experienced two different stages with an abrupt transition between them under all

Ling Wu; Ji-xin Chen; Ming-yue Liu; Yi-wang Bao; Yan-chun Zhou

2009-01-01

4

Study of Al 2O 3 coatings on AISI 316 stainless steel obtained by controlled atmosphere plasma spraying (CAPS)  

Microsoft Academic Search

The tribological behaviour of Al2O3 coatings on AISI 316 stainless steel, obtained by the process of controlled atmosphere plasma spraying (CAPS), is studied in this work. Atmospheric plasma spraying (APS) and high pressure plasma spraying (HPPS) were applied in order to produce these coatings. The APS coatings exhibited lower microhardness values compared to the values of HPPS coatings. Regarding the

Ch. I. Sarafoglou; D. I. Pantelis; S. Beauvais; M. Jeandin

2007-01-01

5

Al, Si, and Al–Si Coatings to Improve the High-Temperature Oxidation Resistance of AISI 304 Stainless Steel  

Microsoft Academic Search

Oxidation resistance of chromium steels is due to the formation of Cr2O3 on the surface. However, this surface layer destabilizes above 1,000 °C and does not protect the metal. In this study, three\\u000a types of coatings were applied to AISI 304 stainless steel (SS), and the microstructure and oxidation resistance of the coatings\\u000a were investigated. Aluminum coating, silicon coating, and the

Morteza Zandrahimi; Javad Vatandoost; Hadi Ebrahimifar

6

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

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

The formation of intermetallics in dissimilar Ti6Al4V\\/copper\\/AISI 316 L electron beam and Nd:YAG laser joints  

Microsoft Academic Search

The welds of titanium alloys with steels suffer from the brittleness of resulting intermetallic compounds. In present study, we report the feasibility of Ti6Al4V to stainless steel AISI 316L welding through pure copper interlayer carried out by electron beam and pulsed Nd:YAG laser. The nature and the localization of intermetallic phases in these welds have been studied by SEM, EDS,

I. Tomashchuk; P. Sallamand; H. Andrzejewski; D. Grevey

2011-01-01

9

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

10

Microstructure and Corrosion Properties of AlCoCrFeNi High Entropy Alloy Coatings Deposited on AISI 1045 Steel by the Electrospark Process  

NASA Astrophysics Data System (ADS)

Electrospark deposition (ESD) was employed to clad the AlCoCrFeNi high-entropy alloy (HEA) on AISI 1045 carbon steel. The relationship between the microstructure and corrosion properties of the HEA-coated specimens was studied and compared with that of the copper-molded cast HEA material. Two major microstructural differences were found between the cast HEA material and the HEA coatings. First, the cast material comprises both columnar and equiaxed crystals with a columnar-to-equiaxed transition (CET), whereas the HEA coatings consist of an entirely columnar crystal structure. The CET phenomenon was analyzed based on Hunt's criterion. Second, unlike the cast HEA material, there was no obvious Cr-rich interdendritic segregation and nano-sized precipitate distributed within the dendrites of the HEA coating. With regard to corrosion properties, the corrosion current of the HEA-coated specimen was significantly lower than for the 1045 steel and the cast HEA material. This was attributed to the ESD specimen having a relatively high Cr oxide and Al oxide content at the surface. Moreover, for the ESD specimen, the absence of Cr-rich interdendritic phase and second-phase precipitation resulted in a relatively uniform corrosion attack, which is different from the severe galvanic corrosion attack that occurred in the cast specimen.

Li, Q. H.; Yue, T. M.; Guo, Z. N.; Lin, X.

2013-04-01

11

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

12

Wear and friction behaviour of duplex-treated AISI 4140 steel  

Microsoft Academic Search

In this study samples of AISI 4140 steel were pretreated by plasma nitriding and coated with two different physical vapour deposited coatings (TiN and TiAlN). A hardened AISI 4140 sample and a coated sample were also included in the investigation. To examine the influence of the nitrided zone on the performance of the coating–substrate composite, two different nitriding conditions —

B. Podgornik; J. Vižintin; O. Wänstrand; M. Larsson; S. Hogmark

1999-01-01

13

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

14

Tool wear when turning hardened AISI 4340 with coated PCBN tools using finishing cutting conditions  

Microsoft Academic Search

Tool wear is one of the most important aspects in metal cutting, especially when machining hardened steels. The present work shows the results of tool wear, cutting force and surface finish obtained from the turning operation on hardened AISI 4340 using PCBN coated and uncoated edges. Three different coatings were tested using finishing conditions: TiAlN, TiAlN-nanocoating and AlCrN. The lowest

Reginaldo T. Coelho; Eu-Gene Ng; M. A. Elbestawi

2007-01-01

15

Comparing the Formability of AISI 304 and AISI 202 Stainless Steels  

NASA Astrophysics Data System (ADS)

The formability of AISI 202 austenitic stainless steel was compared with that of type AISI 304 stainless steel. Type 202 is a low-nickel austenitic stainless steel alloyed with manganese and nitrogen. In this study, the formability of the two grades was examined using Erichsen cupping tests and room temperature uniaxial tensile tests performed at various angles to the rolling direction. AISI 202 appears to work-harden at a slightly higher rate than AISI 304, even though the austenite in type 202 is more stable than that in 304 with respect to the formation of deformation-induced ?' martensite. Although both grades are predicted to be susceptible to earing during deep drawing, AISI 202 displays a higher work-hardening exponent, higher average normal anisotropy, and a higher limiting drawing ratio than AISI 304. Similar cup heights were measured during Erichsen cupping tests, confirming that the two grades have very similar deep drawing properties. The results of this investigation therefore suggest that AISI 202 is a suitable alternative for AISI 304 in applications requiring good deep drawing properties.

du Toit, M.; Steyn, H. G.

2012-07-01

16

Microscopic study of bacterial attachment on AISI 304 and AISI 316 stainless steel surfaces  

Microsoft Academic Search

The paper reports the investigations of properties stemming from bacterial adhesion (biofilm) on stainless steel (AISI 304 and AISI 316) surfaces for application in the petroleum industry. These were carried out using epifluorescence microscopy, environmental scanning electron microscopy (ESEM) and atomic force microscopy (AFM).The strains identified by morphological characterization and biochemical tests and results showed that the extracellular polymeric substances

Bassam A El Gammudi; Izzeddin M El Musrati; Asma M Bourgheya; Adel A El Tawil; Judit Telegdi

2008-01-01

17

The kinetics of ?-phase precipitation in AISI310 and AISI316 steels  

NASA Astrophysics Data System (ADS)

The kinetics of ?-phase precipitation in AISI 310 and AISI 316 steels were studied. An attempt was made to express the rate of precipitation of ?-phase with formal kinetic theory equations. It was established that rate of precipitation of ?-phase is a function of temperature mat agrees with the Johnson-Mehl equation.

Barcik, Jan

1983-03-01

18

Hard turning: AISI 4340 high strength low alloy steel and AISI D2 cold work tool steel  

Microsoft Academic Search

The aim of this paper is to evaluate the machinability of hardened steels at different levels of hardness and using a range of cutting tool materials. More specifically, the work was focused on the machinability of hardened AISI 4340 high strength low alloy steel and AISI D2 cold work tool steel. The tests involving the AISI 4340 steel were performed

J. G. Lima; R. F. Ávila; A. M. Abrão; M. Faustino; J. Paulo Davim

2005-01-01

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 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

20

A comparison of borides formed on AISI 1040 and AISI P20 steels  

Microsoft Academic Search

In this study, some properties of borides formed on the AISI 1040 and AISI P20 steel substrates were investigated. Boronizing was performed at 800, 875, and 950°C for 2, 4, 6, and 8h by using Ekabor 2 powders. The hardness of borides was about 1500HVN. The depth of boride layers was ranged from 10?m to 180?m. The presence of borides

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

2007-01-01

21

Tribological properties of plasma nitrided and hard coated AISI 4140 steel  

Microsoft Academic Search

In the present study, samples made of AISI 4140 steel pre-treated with plasma nitriding and coated with different PVD coatings (TiN, TiAlN and ta-C) were investigated in terms of their microhardness, surface roughness, scratch adhesion and dry sliding wear resistance. Wear tests, in which duplex-treated pins were mated to hardened ball bearing steel discs, were performed with a pin-on-disc machine.

B. Podgornik; J Vižintin; O Wänstrand; M Larsson; S Hogmark; H Ronkainen; K Holmberg

2001-01-01

22

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

23

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

24

Residual stresses in turned AISI 4340 steel  

Microsoft Academic Search

The residual-stress distribution in the surface region of workpieces of annealed AISI 4340 steel that is turned under unlubricated\\u000a conditions is determined using a deflection etching technique. The absolute value of the residual stresses at the machined\\u000a surface are low and increase with an increase in depth beneath the machined surface to a maximum. They then decrease with\\u000a a further

A. B. Sadat; J. A. Bailey

1987-01-01

25

Intergranular corrosion of AISI 316L steel  

Microsoft Academic Search

The degree of sensitization (DOS) of austenitic stainless steel AISI 316L to intergranular corrosion (IGC) was determined by means of electrolytic etching in oxalic acid and electrochemical potentiokinetic reactivation (EPR) tests completed by metallographic inspection. An analytical electron microscope, equipped with an energy-dispersive X-ray spectrometer, was used to examine the microstructure of the steel investigated, which had been annealed for

Martin Matula; Ludmila Hyspecka; Milan Svoboda; Vlastimil Vodarek; Catherine Dagbert; Jacques Galland; Zuzana Stonawska; Ludek Tuma

2001-01-01

26

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

27

Sensitization evaluation of the austenitic stainless steel AISI 304L, 316L, 321 and 347  

Microsoft Academic Search

This work presents a systematic investigation of the influence of time and temperature in the sensitization of stainless steel AISI 304L, AISI 316L, AISI 321 and AISI 347 pipes used in petroleum refining plants. The sensitization was assessed by Scanning Electron Microscopy (SEM) according to ASTM A-262 and by the Double Loop Electrochemical Potentiokinetic Reactivation test (DLEPR). The results showed

A. S. Lima; A. M. Nascimento; H. F. G. Abreu; P. de Lima-Neto

2005-01-01

28

Investigation of the mechanical properties of friction-welded joints between AISI 304L and AISI 4340 steel as a function rotational speed  

Microsoft Academic Search

In this study, standard AISI 304L austenitic stainless steel and AISI 4340 steel couple were welded by friction welding process using five different rotational speeds. The joining performances of AISI 304L\\/AISI 4340 friction-welded joints were studied and the influences of rotational speed on the microstructure and mechanical properties of the welded joints were also estimated. The microstructural properties of heat

N. Özdemir

2005-01-01

29

AISI waste oxide recycling program. Final technical report.  

National Technical Information Service (NTIS)

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 ...

E. Aukrust K. B. Downing B. Sarma

1995-01-01

30

Fusion Welding of Irradiated AISI 304L Stainless Steel Tubings.  

National Technical Information Service (NTIS)

Fast reactor irradiated AISI 304L stainless steel tubing was fusion-welded using conventional inert gas-tungsten arc welding (GTAW) procedures which were adapted for remote operation. Metallographic examination of weld joints sometimes revealed porosity i...

M. M. Hall A. G. Hins J. R. Summers D. E. Walker

1978-01-01

31

Swelling behavior of titanium-modified AISI 316 alloys  

SciTech Connect

It appears that titanium additions to stainless steels covering a wide compositional range around the specifications of AISI 316 result only in an increased delay period before neutron-induced void swelling proceeds. Once swelling is initiated the post transient behavior of both annealed and cold-worked titanium-modified steels is quite consistent with that of AISI 316, approaching a relatively temperature-independent swelling rate of approx. 1% per dpa.

Garner, F.A.; Brager, H.R.; Puigh, R.J.

1984-01-01

32

Surface Fatigue Life of CBN and Vitreous Ground Carburized and Hardened AISI 9310 Spur Gears.  

National Technical Information Service (NTIS)

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 9...

D. P. Townsend P. R. Patel

1988-01-01

33

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

34

Use of AISI 316 austenitic steel in power plant  

SciTech Connect

Power plant commissioned in the late '60s and early '70s required materials which would withstand the conditions imposed by the higher steam temperatures and pressures employed. The austenitic stainless steel AISI 316 has proved to be the most favorable material for components for which very precise dimensional stability is not essential. The paper assesses the properties that favor the choice of AISI 316, details the shortcomings that limit its use, specifies the precautions that should be taken in design, manufacture and operation, suggests ways in which improvements in properties might be obtained and examines possible future uses for the material.

Wyatt, L.M.

1980-11-01

35

Use of AISI 316 austenitic steel in power plant  

Microsoft Academic Search

Power plant commissioned in the late '60s and early '70s required materials which would withstand the conditions imposed by the higher steam temperatures and pressures employed. The austenitic stainless steel AISI 316 has proved to be the most favorable material for components for which very precise dimensional stability is not essential. The paper assesses the properties that favor the choice

Wyatt

1980-01-01

36

Pulse current plasma assisted electrolytic cleaning of AISI 4340 steel  

Microsoft Academic Search

An electrolytic plasma process (EPP) for cleaning AISI 4340 steel was performed in a 10% solution of sodium bicarbonate operated at 70°C. The effects of the pulse frequency (f) and duty cycle (?) on the surface morphology, microstructure, mechanical and corrosion properties were investigated. Compared to the conventional DC process, the pulsed EPP cleaning resulted in reduced surface roughness and

A. Yerokhin; A. Pilkington; A. Matthews

2010-01-01

37

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

38

Wear resistance of quenched and tempered AISI 4137H steel  

Microsoft Academic Search

Abrasive wear resistance of quenched and tempered AISI 4137H steel was studied using the dry sand\\/rubber wheel test. The variables studied included hardness, tempering temperature, and cleanliness of the steel. The effect of sulfide inclusions on the relative wear performance of the steel was examined. Debris from the wear tests was analyzed using SEM and sieve analysis. The effects of

Murali D. Tumuluru

1986-01-01

39

Tribocorrosion behaviour of duplex surface treated AISI 304 stainless steel  

Microsoft Academic Search

This paper reports on the corrosion and tribocorrosion behaviour of AISI 304 stainless steel surfaces after processed by a duplex treatment consisting of plasma nitriding and a CrN coating by physical vapour deposition (PVD). An industrial evaporation PVD reactor chamber has been adapted to produce a nitriding layer using arc-enhanced glow discharge (AEGD) in the presence of nitrogen gas. Subsequently,

A. de Frutos; M. A. Arenas; G. G. Fuentes; R. J. Rodríguez; R. Martínez; J. C. Avelar-Batista; J. J. de Damborenea

2010-01-01

40

Colloquium on Large Scale Improvement: Implications for AISI  

ERIC Educational Resources Information Center

The Alberta Initiative for School Improvement (AISI) is a province-wide partnership program whose goal is to improve student learning and performance by fostering initiatives that reflect the unique needs and circumstances of each school authority. It is currently ending its third cycle and ninth year of implementation. "The Colloquium on Large…

McEwen, Nelly, Ed.

2008-01-01

41

Irradiation-induced swelling in solution annealed AISI 316  

Microsoft Academic Search

Swelling in solution annealed AISI 316 has been empirically described as a function of temperature and fluence. An equation, suitable for design purposes, has been developed from an analysis of all of the available swelling data and complementary investigations. The equation is bi-linear in nature and incorporates different temperature dependent functions for both the maximum linear swelling rate parameter and

J. F. Bates; R. A. Weiner; M. K. Korenko

1978-01-01

42

Investment cast AISI H13 tooling for automotive applications  

Microsoft Academic Search

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 material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns

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

1995-01-01

43

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

44

Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 1. Experimental Results (Preprint).  

National Technical Information Service (NTIS)

This paper is the first part of a three-part series which investigates the rolling contact fatigue (RCF) initiation and spall propagation characteristics of three bearing materials, namely AISI 52100, VIM-V AR AISI M50, and VIM-V AR M50NiL steels. Althoug...

J. W. Cooke K. L. Thompson L. Rosado N. H. Forster

2009-01-01

45

Role of molybdenum on the AISI 316L oxidation at 900 °C  

Microsoft Academic Search

In situ X-ray diffraction was used to study the oxide formation on AISI 316L stainless steel (SS) specimens during isothermal\\u000a oxidation at 900 °C in air. Results were compared with those obtained on AISI 304 SS to determine the role of molybdenum on\\u000a the oxidation process for the AISI 316L SS specimens. Our results show that molybdenum plays a major protective role

H. Buscail; S. El Messki; F. Riffard; S. Perrier; R. Cueff; C. Issartel

2008-01-01

46

Delayed cracking in plasma nitriding of AISI 420 stainless steel  

Microsoft Academic Search

The phenomenon of delayed cracking in nitrided layers after DC-plasma nitriding of AISI 420 steel has been observed by optical microscopy. Prior to the plasma treatment, the samples were austenitized at 1303 K for 30 min and then oil quenched. Two tempering conditions were assessed: one group was tempered at 673 K, while another group was tempered at 943 K.All samples were subjected to

W. Tuckart; E. Forlerer; L. Iurman

2007-01-01

47

AISI waste oxide recycling program. Final technical report  

Microsoft Academic Search

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

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

1995-01-01

48

Wear resistance of quenched and tempered AISI 4137H steel  

Microsoft Academic Search

Abrasive wear resistance of quenched and tempered AISI 4137H steel was studied using the dry sand\\/rubber wheel test. The variables\\u000a studied included hardness, tempering temperature, and cleanliness of the steel. The effect of sulfide inclusions on the relative\\u000a wear performance of the steel was examined. Debris from the wear tests was analyzed using SEM and sieve analysis. The effects\\u000a of

Murali d. Tumuluru

1986-01-01

49

Corrosion behavior of ion nitrided AISI 316L stainless steel  

Microsoft Academic Search

In the present work the corrosion susceptibility of ion nitrided AISI 316L stainless steel was investigated for two different nitriding times and compared with the corrosion susceptibility of the untreated material. Plasma nitriding for short times (30 min) produced the “S” phase or expanded austenite (?N), with a thickness of ?5 ?m and a micro-hardness of 1300–1400 HV0.025 (6.5 times higher than

L. Nosei; S. Farina; M. Ávalos; L. Nachez; B. J. Gómez; J. Feugeas

2008-01-01

50

Transporte electronico en nanoestructuras de carbono  

NASA Astrophysics Data System (ADS)

The aim of this work is the study of the electronic transport properties in several structures made of carbon nanotubes. This dissertation is divided in four chapters: (1) Chapter 1: Carbon Nanotubes. This chapter is a brief review of the foundations of carbon nanotubes (CNT). Main properties of CNT are explained. The subject developed here is important for the understanding of the results obtained in the bulk of this thesis. We carry out, in the first part of this chapter, an historical review of the discovering of CNT, that includes the history of the discovering of fullerenes, the predecessors for carbon nanotubes. Afterwards, a revision of the different methods for synthesizing nanotubes is done. The main part of this chapter treats of the description of the geometry, properties and electronic structure of CNT. Many equations deduced here will be used later. Finally, we discuss some research lines related to carbon nanotubes. (2) Chapter 2: Theoretical and numerical method. In this chapter we describe the numerical method we have developed to obtain the results presented in this work. For this purpose it is necessary to describe previously the theoretical method on which our calculations are based. We extensively explain the Green's function and its properties. A large part of our calculations are based in the obtention the GF of the system under study. This chapter finishes with the application of the equations described in order to obtain electronic properties associated with pure carbon nanotubes as an example of use. Anyway, these previous results will be used later. (3) Chapter 3: Cavities made of nanotubes. We denote as a cavity to the structure formed with a carbon nanotube sandwiched between other two carbon nanotubes (contacts), provided that the central region is wider than these contacts. In this chapter we perform some calculations of the properties associated to the electronic transport in cavities, as the local density of states and the transmission function. We analyze the influence of the width of the cavity and the distance between them (in the case of multiple cavities). Some interesting results are obtained in these calculations which have been published in international journals (Jodar et al. 2006, Jodar y Perez-Garrido 2007). We emphasize the presence of quasi-localized states in the cavities, which affects to the transmission function, the behaviour of some cavities formed with semi-conductor as quantum dots, or the study of the evolution of the system with multiple cavities to the limit of infinite cavities. (4) Chapter 4: Bloch Oscillations. In this chapter we investigate the properties of carbon nanotubes under a constant electric field. This configuration show Bloch oscillations, according to the work of Bloch and Zener. We study here the dynamics of these oscillations for different geometries as a function of the electric field applied. Specially, the behaviour of the occupation probability and the averaged quadratic displacement as a function of time. We have not found bibliography that deals with this phenomenon in Carbon Nanotubes, which is the aim of this chapter. We first study the behaviour of electrons in pure carbon nanotubes in a constant electric field, for different lengths of the CNT and different values of the electric field applied. We show how wavefunctions oscillate with a period that coincides with that given by theoretical expressions of Bloch oscillations for linear chains of atoms. Besides, we show the different kind of behaviour of localized and extended waves. In the final part of this chapter we apply a constant electric field to the structure studied in the chapter 3, i.e., the cavity. We show in this case that, besides Bloch oscillations, electrons can be confined in certain regions only by inserting the nanotube in an electric field.

Jodar Ferrandez, Esther

51

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

Microsoft Academic Search

Annealed specimens of AISI 304 and 316 were irradiated in the EBR-II fast reactor at approx. 400°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

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

1983-01-01

52

Some mechanical properties of borided AISI H13 and 304 steels  

Microsoft Academic Search

In the present study, mechanical properties of borides formed on AISI H13 hot work tool and AISI 304 stainless steels have been investigated. Both steels have high chromium content and have a widespread use in the engineering application. Boriding treatment was carried out in slurry salt bath consisting of borax, boric acid, and ferrosilicon at temperature range of 800–950°C for

Sukru Taktak

2007-01-01

53

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

54

Evaluation of AISI 316L stainless steel welded plates in heavy petroleum environment  

Microsoft Academic Search

This work presents the study done on the effect of welding heating cycle on AISI 316L austenitic stainless steel corrosion resistance in a medium containing Brazilian heavy petroleum. AISI 316L stainless steel plates were welded using three levels of welding heat input. Thermal treatments were carried out at two levels of temperatures (200 and 300°C). The period of treatment in

Cleiton Carvalho Silva; Jesualdo Pereira Farias; Hosiberto Batista de Sant’Ana

2009-01-01

55

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

56

Effect of Heat Treatment on Microstructure of Modified Cast AISI D3 Cold Work Tool Steel  

Microsoft Academic Search

The effects of heat treatment on the microstructure of modified cast high chromium high carbon AISI D3 steel were studied. The modified AISI D3 steel was developed by replacing part of chromium with niobium and titanium, in which chromium carbide was partially replaced with MC carbides. The cast samples produced by investment casting were heat treated under different conditions. The

Shahram Kheirandish; Hasan Saghafian; Jalal Hedjazi; Mohammad Momeni

2010-01-01

57

Influence of Aluminum and Aluminum Plus Silicon Additions on the Mechanical Properties of AISI 4340 Steel.  

National Technical Information Service (NTIS)

The softening which occurs on tempering AISI 4340 steel is shown to be retarded by additions of aluminum or combinations of aluminum and silicon. The ''500 exp 0 F embrittlement'' phenomenon in AISI 4340 steel occurs at higher tempering temperatures in th...

M. S. Bhat

1977-01-01

58

The semiconducting properties of passive films formed on AISI 316 L and AISI 321 stainless steels: A test of the point defect model (PDM)  

Microsoft Academic Search

The semiconductor properties of passive films formed on AISI 316L in 1M H2SO4 in three temperatures and AISI 321 in 0.5M H2SO4 were studied by employing Mott–Schottky analysis in conjunction with the point defect model (PDM). Based on the Mott–Schottky analysis in conjunction with PDM, it was shown that the calculated donor density decreases exponentially with increasing passive film formation

A. Fattah-alhosseini; F. Soltani; F. Shirsalimi; B. Ezadi; N. Attarzadeh

2011-01-01

59

Tribological properties of FeAl intermetallics under dry sliding  

Microsoft Academic Search

The tribological properties of FeAl intermetallics under dry sliding against AISI52100 steel at ambient conditions were studied on an Optimol SRV oscillating friction and wear tester in a ball-on-disc contact configuration. Effects of load and sliding speed on tribological properties of the FeAl intermetallics were investigated. The worn surfaces of the FeAl intermetallics were examined with a scanning electron microscopy

Jun Yang; Peiqing La; Weimin Liu; Qunji Xue

2004-01-01

60

Strain aging of AISI 430 ferritic stainless steel  

SciTech Connect

High stress corrosion resistance and relatively low production costs are the main reasons for the increasing application of AISI 430 ferritic stainless steels. Problems such as loss of ductility and toughness when exposed to elevated temperatures, occurring in these steels, for instance, during welding, are being dealt with, and the main challenge now is to explore attractive, non-conventional properties that the material might exhibit, in order to offer alternative choices for engineering design. This was the idea underlying the present work, in which the phenomenology and kinetics of strain aging in a commercial AISI 430 stainless steel were characterized, by means of electrical resistivity measurements and tensile tests. The values of the kinetic parameters were determined based on the changes in electrical resistivity, a technique which has been used for many years to study the effects of impurities and phase transitions in metals and alloys. Measurements of electrical resistivity performed at the liquid nitrogen temperature have been employed to characterize the kinetics of strain aging in drawn high carbon steels, disclosing important phenomena related to the decomposition of cementite in this class of steels.

Buono, V.T.L.; Gonzalez, B.M. [Univ. Federal de Minas Gerais, Belo Horizonte (Brazil). Dept. de Engenharia Metalurgica e de Materiais; Andrade, M.S. [Fundacao Centro Tecnologico de Minas Gerais, Belo Horizonte (Brazil)

1997-12-22

61

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

62

The Effect of Grain and Carbine Refinement on the Isothermal Transformation Characteristics of AISI 52100 Steel.  

National Technical Information Service (NTIS)

A study of the microstructure and mechanical properties of isothermally-transformed AISI 52100 bearing steel was conducted. Standard spheroidized annealed and thermomechanically grain-refined materials were compared. Heat treatment consisted of austenitiz...

D. M. Tufte

1981-01-01

63

Anodic Behaviour of AISI 304 Stainless Steel Straining Electrodes in Aqueous Chloride Solutions.  

National Technical Information Service (NTIS)

Current densities on the bare metal resulting from rapidly straining electrodes of AISI 304 stainless steel were determined. Experiments were performed at different applied potentials, in neutral and acidified NaCl solutions, at room temperature and at 90...

R. M. Schroeder I. L. Mueller

1983-01-01

64

Plastic Concentration Factors in Flat Notched Specimens of AISI 4340 Steel.  

National Technical Information Service (NTIS)

The Neuber rule is evaluated using an appropriate analytic representation of the stress-strain curve of AISI 4340 steel and predictions of maximum notch strain versus nominal net section stress are developed. The theoretical results, when compared with te...

R. Papirno

1970-01-01

65

The strengthening mechanisms in modified AISI 316 stainless steels  

SciTech Connect

The flow strength of a series of modified type AISI 316 austenitic stainless steels with stabilizing additions and with combined copper and stabilizing additions were evaluated after various thermo-mechanical treatments at elevated temperatures by using the load relaxation technique. The test results showed that there is a synergistic increase in strength when both copper and stabilizing additions are made and combined with prior cold work before stabilization treatment. Microstructural examination showed that copper increases the nucleation rate of MC type precipitation on grain matrix dislocations produced by cold work creating a fine distribution of these precipitates. This precipitation process enhances the strength of the steels and improves microstructural stability at elevated temperatures. 13 refs., 18 figs., 2 tabs.

Carolan, R.A.; Li, Che-Yu; Maziasz, P.J.; Swindeman, R.W.; Todd, J.A.

1987-04-01

66

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

67

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

68

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

69

Fluidized-bed and salt-bath heat treating (AISI 4130 and 4340 alloy steels)  

Microsoft Academic Search

Using commercial alloy steels AISI 4130 and AISI 4340, a series of heat-treating, parametric studies were performed on specimens in both an electric fluidized-bed furnace and an electric neutral salt-bath furnace. An evaluation of heat-treating methods was performed by comparing tensile test data for the two alloy steels. Surface characterization of test specimens was performed using Auger analyses to discern

Cyrus

1983-01-01

70

Fluidized-bed and salt-bath heat treating (AISI 4130 and 4340 alloy steels)  

Microsoft Academic Search

Using commercial alloy steels AISI 4130 and AISI 4340, a series of heat treating parametric studies were performed on specimens in both an electric fluidized-bed furnace and an electric neutral-salt-bath furnace. An evaluation of heat treating methods was performed by comparing tensile-test data for the two alloy steels. Surface characterization of test specimens was performed using Auger analyses to discern

Cyrus

1983-01-01

71

Sliding Friction and Wear Behavior of Pack-Boronized AISI 1050, 4140, and 8620 Steels  

Microsoft Academic Search

This paper describes the dry sliding friction and wear performance of boronized AISI 1050, 4140, and 8620 steels with the Fe2B phase coating on the surface. The studies were carried out using a pin-on-disc arrangement. The disc material was made of carburized AISI 1020 steel. For the normalized (untreated) steels, two basic wear regimes were observed; namely, oxidative and severe

Yavuz Soydan; Sakip Köksal; Ahmet Demirer; Veli Çelik

2008-01-01

72

High speed end milling of AISI 304 stainless steel using new geometrically developed carbide inserts  

Microsoft Academic Search

AISI 304 stainless steel possesses some properties, such as low thermal conductivity and high ductility that make them be classified under materials of poor machinability that exhibit a lot of difficulties during cutting. This work reports an experimental study on the performance of multilayered (TiN\\/TiCN\\/TiN) carbide inserts recently developed for end-milling of AISI 304 stainless steels. The length of chip-tool

K. A. Abou-El-Hossein; Z. Yahya

73

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

74

Studies on Direct Laser Cladding of SiC Dispersed AISI 316L Stainless Steel  

Microsoft Academic Search

In the present study, attempts have been made to develop SiC dispersed (5 and 20 wt pct) AISI 316L stainless steel matrix\\u000a composite by direct laser cladding with a high power diode laser. Direct laser cladding has been carried out by melting the\\u000a powder blends of AISI 316L stainless steel and SiC (5 and 20 wt pct) and, subsequently, depositing it on mild steel

Jyotsna Dutta Majumdar; Lin Li

2009-01-01

75

Material transfer phenomena and failure mechanisms of a nanostructured Cr–Al–N coating in laboratory wear tests and an industrial punch tool application  

Microsoft Academic Search

In this research, CrAlN and TiN coatings were deposited on AISI M2 tool steel substrate test coupons and on industrial punch tools by electron beam plasma-assisted physical vapour deposition (EB-PAPVD). The microstructure and morphology of the coatings were investigated by XRD, XPS, TEM, and SEM with EDX. Pin-on-disc tribotests were conducted on the coatings against AISI 52100 steel counterface material

L. Wang; X. Nie; J. Housden; E. Spain; J. C. Jiang; E. I. Meletis; A. Leyland; A. Matthews

2008-01-01

76

Investment cast AISI H13 tooling for automotive applications  

SciTech Connect

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 material is comparable to the wrought counterpart, the use of investment cast HI 3 tooling directly from patterns made via rapid prototyping is of considerable interest. A metallurgical study of investment cast H13 was conducted to evaluate the mechanical behavior in simulated die casting applications. Variable thickness plate investment castings of AISI H13 hot work die steel were produced and characterized in the as-cast and heat-treated conditions. The characterization included light microscopy and mechanical testing. Wrought samples of standard and premium grade H13 were heat-treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples produced in different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat-treatment, microstructural differences between the wrought material and cast materials were slight regardless of section thickness.The mechanical properties of the cast and heat-treated material proved similar to the properties of the standard heat-treated wrought material. A thermal fatigue testing unit was to con-elate the heat checking susceptibility of H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was observed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat-treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking.

Maguire, M.C.; Baldwin, M.D. [Sandia National Labs., Albuquerque, NM (United States); Hochanadel, P.W.; Edwards, G.R. [Colorado School of Mines, Golden, OH (United States)

1995-07-01

77

Characterization of the oxides formed at 1000 °C on the AISI 316L stainless steel—Role of molybdenum  

Microsoft Academic Search

In the present work, in situ X-ray diffraction (XRD) was used to identify the oxides formed on the AISI 316L stainless steel (SS) during isothermal oxidation at 1000°C, in air. The results were compared with those obtained on the AISI 304 SS in order to better explain the role of molybdenum on the oxidation process of the AISI 316L (containing

H. Buscail; S. El Messki; F. Riffard; S. Perrier; R. Cueff; E. Caudron; C. Issartel

2008-01-01

78

High temperature oxidation of CrTiAlN hard coatings prepared by unbalanced magnetron sputtering  

Microsoft Academic Search

The present research aims to synthesize a multi-component CrTiAlN hard coating for the modification of high-temperature performance, as compared to the traditional TiN and TiAlN coatings. In this work, the quaternary CrTiAlN coatings were deposited on AISI M42 steel substrates by reactive unbalanced magnetron sputtering technique from Cr, Ti and Al elemental targets in Ar+N2 mixture atmosphere, and their high-temperature

Z. F. Zhou; P. L. Tam; P. W. Shum; K. Y. Li

2009-01-01

79

Tribological properties of Fe 3Al–Fe 3AlC 0.5 composites under dry sliding  

Microsoft Academic Search

The tribological properties of Fe3Al composites with 40, 60 and 80wt.% Fe3AlC0.5 under dry sliding against AISI52100 steel at ambient conditions were studied. Effects of load and sliding speed on the tribological properties were investigated. Worn surfaces of the composites were analyzed by scanning electron microscopy. It was found that wear rate of the composites were in the magnitude of

Jun Yang; Peiqing La; Weimin Liu; Jiqiang Ma; Qunji Xue

2005-01-01

80

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

81

Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 2. Stress Modeling (Preprint).  

National Technical Information Service (NTIS)

This is the second part of 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 o...

G. Levesque N. Branch N. H. Forster N. K. Arakere V. Svendsen

2009-01-01

82

Rolling Contact Fatigue Life and Spall Propagation Characteristics of AISI M50, M50 NiL, and AISI 52100. Part 3. Metallurgical Examination (Preprint).  

National Technical Information Service (NTIS)

This is the third part of a three-part series which investigates the rolling contact fatigue initiation and spall propagation characteristics of three bearing materials, namely AISI 52100, VIM-VAR M50, and VIM-VAR M50 NiL steels. While there is substantia...

H. K. Trivedi L. Rosado N. H. Forster W. P. Ogden

2009-01-01

83

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

84

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

85

Dependence on Displacement Rate of Radiation-Induced Changes in Microstructure and Tensile Properties of AISI 304 and 316.  

National Technical Information Service (NTIS)

Annealed specimens of AISI 304 and 316 were irradiated in the EBR-II fast reactor at approx. 400 exp 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 t...

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

1983-01-01

86

The influence of atmospheric humidity and grain size on the friction and wear of AISI 304 austenitic stainless steel  

Microsoft Academic Search

The tribological properties of a ultra-fine AISI 304 austenitic stainless steels obtained by means of a martensitic transformation and subsequent austenite reversion are reported. The effects of the grain size on the wear resistance of such material is, for the first time, investigated as a function of the atmospheric humidity. Decrease of relative humidity in wear tests of AISI 304

G. Bregliozzi; A. Di Schino; J. M. Kenny; H. Haefke

2003-01-01

87

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

88

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

89

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

90

Studies on the Sliding Wear Performance of Plasma Spray Ni-20Cr and Ni3Al Coatings  

NASA Astrophysics Data System (ADS)

Two metallic powders namely Ni-20Cr and Ni3Al were coated on AISI 309 SS steel by shrouded plasma spray process. The wear behavior of the bare, Ni-20Cr and Ni3Al-coated AISI 309 SS steel was investigated according to ASTM Standard G99-03 on a Pin-on-Disc Wear Test Rig. The wear tests were carried out at normal loads of 30 and 50 N with a sliding velocity of 1 m/s. Cumulative wear rate and coefficient of friction (?) were calculated for all the cases. The worn-out surfaces were then examined by scanning electron microscopy analysis. Both the as-sprayed coatings exhibited typical splat morphology. The XRD analysis indicated the formation of Ni phase for the Ni-20Cr coating and Ni3Al phase for the Ni3Al coating. It has been concluded that the plasma-sprayed Ni-20Cr and Ni3Al coatings can be useful to reduce the wear rate of AISI 309 SS steel. The coatings were found to be adherent to the substrate steel during the wear tests. The plasma-sprayed Ni3Al coating has been recommended as a better choice to reduce the wear of AISI 309 SS steel, in comparison with the Ni-20Cr coating.

Kaur, Maninder; Singh, Harpreet; Singh, Balraj; Singh, Bhupinder

2010-01-01

91

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

92

Inductively coupled plasma nitriding of chromium electroplated AISI 316L stainless steel for PEMFC bipolar plate  

Microsoft Academic Search

Chromium electroplated AISI 316L stainless steel was nitrided using inductively coupled plasma (ICP) for application in the bipolar plate of a polymer electrolyte membrane fuel cell (PEMFC). A continuous and thin chromium nitride layer was formed at the surface of the samples after ICP nitriding for 2h at 400°C. The interfacial contact resistance (ICR) and corrosion resistance in simulated PEMFC

D.-H. Han; W.-H. Hong; H. S. Choi; J. J. Lee

2009-01-01

93

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

94

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

95

Passivity and Stress Corrosion Cracking of AISI 316 Stainless Steel in Chloride-Containing Solutions.  

National Technical Information Service (NTIS)

The aim of this thesis is to study the stress corrosion cracking behavior of solution-annealed and quenched AISI 316 stainless steel in chloride containing solutions at temperatures ranging from 150 to 250 C. Stainless steel obtains its relatively good re...

A. D. A. Harbiye

1992-01-01

96

Analysis of the recrystallization and grain growth processes in AISI 316 stainless steel  

Microsoft Academic Search

A theoretical and experimental study on the recrystallization and grain growth processes on AISI 316 stainless steel is here reported. Experimental data are analyzed according to a mathematical model based on statistical assumptions able to describe simultaneously recrystallization and grain growth in metals. Taking into account the classical constitutive equations of the Taylor's theory, the model adopts two parameters: the

A. Di Schino; J. M. Kenny; G. Abbruzzese

2002-01-01

97

Effect of Loading Rate on Creep Properties of AISI Type 316.  

National Technical Information Service (NTIS)

The initial rate of load application was found to have no significant effects on the results of the creep tests on AISI Type 316 at 650C, and therefore a single standard loading rate does not appear to be necessary for this material; however, in general, ...

1970-01-01

98

Microstructural Interpretation of the Fluence and Temperature Dependence of the Mechanical Properties of Irradiated AISI 316.  

National Technical Information Service (NTIS)

The effects of neutron irradiation on the mechanical properties of annealed and 20% cold-worked AISI 316 irradiated in EBR-II were determined for the temperature regime of 370 to 760 exp 0 C for fluences up to 8.4 x 10 exp 22 n/cm exp 2 (E > 0.1 MeV). At ...

G. D. Johnson F. A. Garner H. R. Brager R. L. Fish

1980-01-01

99

Strength and toughness of aisi 304 and 316 at 4 K  

Microsoft Academic Search

Structural design of superconducting magnets in fusion energy devices requires reliable property data at 4 K. Nitrogen-strengthened AISI 304 and 316 stainless steels are considered to be the best currently available low temperature structural alloys on the basis of their fabricability and their potential to meet the US fusion research goals of combined 1000 MPa yield strength and 200 MPa

N. J. Simon; R. P. Reed

1986-01-01

100

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

Microsoft Academic Search

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

J. G. Park; D. Y. Lee

1993-01-01

101

Nitriding using cathodic cage technique of austenitic stainless steel AISI 316 with addition of CH 4  

Microsoft Academic Search

Samples of austenitic stainless steel AISI 316 were nitrided using the cathodic cage technique with the addition of methane in the nitriding atmosphere. The aim was to study the influence of this technique in reducing the precipitation of chromium nitrite and in improving the wear resistance. The results show that there was a significant improvement in such properties when compared

R. R. M. de Sousa; F. O. de Araújo; J. C. P. Barbosa; K. J. B. Ribeiro; J. A. P. da Costa; C ALVESJR

2008-01-01

102

Plasma nitriding of AISI 316L austenitic stainless steels at anodic potential  

Microsoft Academic Search

Plasma nitriding experiments were carried out with pulsed dc glow discharge plasma in ammonia atmosphere at temperatures ranging from 450 to 540°C for 4h. In this process, the AISI 316L austenitic stainless steel samples were set on a plate at anodic potential. The phase composition, the thickness and morphology of the nitrided layer, as well as its surface hardness, were

Y. Li; L. Wang; J. Xu; D. Zhang

103

Effect of Shot Peening on Surface Fatigue Life of Carburized and Hardened AISI 9310 Spur Gears.  

National Technical Information Service (NTIS)

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 d...

D. P. Townsend E. V. Zaretsky

1982-01-01

104

Corrosion Protection of AISI(TM) 1010 Steel by Organic and Inorganic Zinc-Rich Primers.  

National Technical Information Service (NTIS)

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 ...

M. D. Danford M. J. Mendrek

1995-01-01

105

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

106

Thermal Creep Effects on 20% Cold Worked AISI 316 Mechanical Properties.  

National Technical Information Service (NTIS)

The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977 exp 0 K and stresses of 86 MPa to 276 MPa. This resulted in strains up...

D. R. Duncan

1980-01-01

107

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

108

Viscoplastic behaviour of stainless steel AISI 316L under cyclic loading conditions  

Microsoft Academic Search

Summary Experimental results on stainless steel AISI 316L under cyclic loading conditions, at room temperature, showing dependence of the consolidation stress on strain rate are obtained and used for the calibration of a viscoplastic numerical model based on total strain and overstress. An explicit dependence for the evolution of the nonlinear viscosity function on cycle number and strain rate on

A. G. Youtsos; E. Gutierrez; G. Verzeletti

1990-01-01

109

Temperature and potential dependence of crevice corrosion of AISI 316 stainless steel  

Microsoft Academic Search

Crevice corrosion of AISI 316 steel has been investigated in a modified ‘Avesta Cell’. Potentiodynamic scans have been made in sodium chloride solutions of various pH values at different temperatures with and without crevice. The breakthrough potential changes discontinuously with temperature. At all temperatures the attack is localised to the crevice, and the breakthrough potential is lower than for experiments

P. T Jakobsen; E Maahn

2001-01-01

110

Effect of ion nitriding on fatigue behaviour of AISI 4140 steel  

Microsoft Academic Search

Ion nitriding has become a popular thermo-chemical surface treatment, which is being used to develop fatigue and wear characteristics of steels. Besides the increased strength, the formation of high compressive residual stresses in the case region causes remarkable improvement in fatigue properties of steels. In this study, the effect of case depth on fatigue performance of AISI 4140 low alloy

Kenan Genel; Mehmet Demirkol; Mehmet Çapa

2000-01-01

111

Determination of optimum cutting parameters during machining of AISI 304 austenitic stainless steel  

Microsoft Academic Search

High strength, low thermal conductivity, high ductility and high work hardening tendency of austenitic stainless steels are the main factors that make their machinability difficult. In this study determination of the optimum cutting speed has been aimed when turning an AISI 304 austenitic stainless steel using cemented carbide cutting tools. The influence of cutting speed on tool wear and surface

Ihsan Korkut; Mustafa Kasap; Ibrahim Ciftci; Ulvi Seker

2004-01-01

112

Microstructural characterization of the HAZ in AISI 444 ferritic stainless steel welds  

Microsoft Academic Search

Ferritic stainless steel is used as a coating for equipment in the petroleum refining industry. Welding is the main manufacturing and maintenance process used. However, little information on the metallurgical alterations caused by welding of these steels is found in the literature, prompting this study. In this study the authors evaluated the HAZ microstructure of AISI 444 ferritic stainless steel

Cleiton C. Silva; Jesualdo P. Farias; Hélio C. Miranda; Rodrigo F. Guimarães; John W. A. Menezes; Moisés A. M. Neto

2008-01-01

113

Microchemistry characterization by Auger electron spectroscopy of a cold-worked AISI304L stainless steel  

Microsoft Academic Search

Auger electron spectroscopy (AES) has been performed on grain boundaries of an AISI-304L stainless steel. The aim of the work was to study microchemistry at grain boundaries by AES after simulating irradiation effects by cold work followed by heat treatments. The results show that phosphorus was present at interfaces in all material conditions. Sometimes, phosphorus was accompanied by molybdenum and

M. Hernandez-Mayoral; G. de Diego; M Garc??a-Mazar??o

2000-01-01

114

AFM surface imaging of AISI D2 tool steel machined by the EDM process  

Microsoft Academic Search

The surface morphology, surface roughness and micro-crack of AISI D2 tool steel machined by the electrical discharge machining (EDM) process were analyzed by means of the atomic force microscopy (AFM) technique. Experimental results indicate that the surface texture after EDM is determined by the discharge energy during processing. An excellent machined finish can be obtained by setting the machine parameters

Y. H. Guu

2005-01-01

115

Effect of shock duration on the dynamic consolidation of powders. [AISI 9310  

Microsoft Academic Search

A recent advanced model for the shock consolidation of powders predicts, for a powder given distension, the regimes of shock pressure and shock duration expected to yield fully densified compacts of near optimum strength. The model is evaluated in terms of UTS measurements in compacts of rapidly solidified powders of AISI 9310 alloy, shocked to initial shock pressures between 3.6

R. B. Schwarz; P. Kasiraj; T. Jr. Vreeland; T. J. Ahrens

1983-01-01

116

Effects of martensite formation and austenite reversion on grain refining of AISI 304 stainless steel  

Microsoft Academic Search

The austenite–martensite transformation followed by annealing for austenite reversion in AISI 304 stainless steel has been investigated in order to study the effect of this thermo-mechanical process on grain refinement. In particular the effect of cold reduction, annealing temperature and annealing times have been analysed. After getting ultrafine grains the effect of the grain size on the hardness and on

A. DI Schino; I. Salvatori; J. M. Kenny

2002-01-01

117

Residual stress analysis in orthogonal machining of standard and resulfurized AISI 316L steels  

Microsoft Academic Search

Residual stresses induced by orthogonal cutting in AISI 316L standard and resulfurized steels have been investigated, with attention given to the role played by the cutting parameters, such as cutting speed, feed rate, tool geometry and tool coating. Depth profiles of residual stress have been determined using the X-ray diffraction technique. The effect of cutting conditions and tool nature on

R. M’Saoubi; J. C. Outeiro; B. Changeux; J. L. Lebrun; A. Morão Dias

1999-01-01

118

Process parameter influence on performance of friction taper stud welds in AISI 4140 steel  

Microsoft Academic Search

Friction taper stud welding is a new variant of friction welding which has been developed from the principles of friction hydro-pillar processing. This paper considers the effect of weld process parameters on weld defects, macrostructure and mechanical properties in AISI 4140 steel. It also presents 3D residual stress data for a typical friction taper stud weld. Applied downwards force, rotational

D. G. Hattingh; D. L. H. Bulbring; A. Els-Botes; M. N. James

2011-01-01

119

A Fuzzy Model for Predicting Surface Roughness in Plasma Arc Cutting of AISI 4140 Steel  

Microsoft Academic Search

In the present study, fuzzy logic (a tool in artificial intelligence) was used for the prediction of cutting parameters in plasma arc cutting process of AISI 4140 steel. The parameters considered in this study were plasma arc current, cutting speed and thickness of cut material. Fuzzy–rule based modeling was employed for prediction of surface roughness. These models can be effectively

Cebeli Özek; Ula? Çayda?; Engin Ünal

2011-01-01

120

A Fuzzy Model for Predicting Surface Roughness in Plasma Arc Cutting of AISI 4140 Steel  

Microsoft Academic Search

In the present study, fuzzy logic (a tool in artificial intelligence) was used for the prediction of cutting parameters in plasma arc cutting (PAC) process of AISI 4140 steel. The parameters considered in this study were plasma arc current, cutting speed, and thickness of cut material. Fuzzy rule–based modeling was employed for prediction of surface roughness. These models can be

Cebeli Özek; Ula? Çayda?; Engin Ünal

2012-01-01

121

Shielded metal arc welding of AISI 4340 alloy steel. Welding procedure specification  

SciTech Connect

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 (F-4, A-1).

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

1985-08-01

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

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

124

Deformation and failure mechanism in AISI 4340 steel under ballistic impact  

Microsoft Academic Search

Deformation and failure mechanism in quench-hardened AISI 4340 steel under ballistic impact is investigated. The influence of microstructure on damage evolution is also evaluated. Strain localization and shear failure along adiabatic shear bands are the dominant deformation and failure mechanisms. The time and critical strain for the commencement of strain localization is influenced by strain rate and microstructure. The microstructure

A. G. Odeshi; S. Al-ameeri; S. Mirfakhraei; F. Yazdani; M. N. Bassim

2006-01-01

125

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

126

Mechanical and technological analysis of AISI 304 butt joints welded with capacitor discharge process  

Microsoft Academic Search

In the present work, the capacitor discharge welding process (CDW) applied on AISI 304 circular bars was studied. The CDW process is essentially an electrical resistance welding technology, realized through current pulses of high intensity and discharged by large capacitors; the process allows to reduce stress concentration effects at the weld toe, obtaining thin welds and achieve good material integrity.CDW

V. Dattoma; F. Palano; F. W. Panella

2010-01-01

127

Experimental study of wire electrical discharge machining of AISI D5 tool steel  

Microsoft Academic Search

This paper presents an experimental investigation of the machining characteristics of AISI D5 tool steel in wire electrical discharge machining process. During experiments, parameters such as open circuit voltage, pulse duration, wire speed and dielectric fluid pressure were changed to explore their effect on the surface roughness and metallurgical structure. Optical and scanning electron microscopy, surface roughness and microhardness tests

Ahmet Hasçalýk; Ula? Çayda?

2004-01-01

128

Studies on Direct Laser Cladding of SiC Dispersed AISI 316L Stainless Steel  

NASA Astrophysics Data System (ADS)

In the present study, attempts have been made to develop SiC dispersed (5 and 20 wt pct) AISI 316L stainless steel matrix composite by direct laser cladding with a high power diode laser. Direct laser cladding has been carried out by melting the powder blends of AISI 316L stainless steel and SiC (5 and 20 wt pct) and, subsequently, depositing it on mild steel (0.15 pct C steel) in a layer by layer fashion to develop a coupon of 100 mm2 × 10 mm dimension. A continuous, defect-free (microcracks and micro- or macroporosities), and homogeneous microstructure is formed, which consists of a dispersion of partially dissolved SiC (leading to formation of very low fraction of Cr3C2 and Fe2Si) in grain-refined austenite. The microhardness of the clad layer increases from 155 VHN to 250 to 340 VHN (for 5 wt pct SiC dispersed) and 450 to 825 VHN (for 20 wt pct SiC dispersed) as compared to 155 VHN of commercially available AISI 316L stainless steel. The corrosion rate in 3.56 wt pct NaCl solution is significantly reduced in 5 wt pct SiC dispersed steel; however, 20 wt pct SiC dispersed steel showed a similar behavior as the commercially available AISI 316L stainless steel. The processing zone for the development of a defect-free microstructure with improved properties has been established.

Majumdar, Jyotsna Dutta; Li, Lin

2009-12-01

129

Microstructue and Mechanical Properties of AISI 4340 Steel Modified with Aluminum and Silicon.  

National Technical Information Service (NTIS)

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 modifie...

M. S. Bhat

1977-01-01

130

Problems in laser repair cladding a surface AISI D2 heat-treated tool steel  

Microsoft Academic Search

The aim of the present work is to establish the relationship between laser cladding (LC) process parameters (power, process speed, and powder feed rate) and AISI D2 tool steel metallurgical transformations, with the objective of optimizing the processing conditions during real reparation. It has been deposited H13 tool steel powder on some steel substrates with different initial metallurgical status (annealed

J. J. Candel; V. Amigó; J. A. Ramos; D. Busquets

2011-01-01

131

Effect of high temperature annealing on texture and microstructure on an AISI444 ferritic stainless steel  

Microsoft Academic Search

AISI 444 is a Mo-alloyed ferritic stainless steel which presents good naphthenic corrosion resistance, making it attractive for applications in petroleum refining plants; however, good formability is also important. To achieve good formability with this alloy the annealing process is crucial. The annealing temperature in ferritic stainless steel is usually around 850 °C, which falls in the range of sigma phase

H. F. G. de Abreu; A. D. S. Bruno; S. S. M Tavares; R. P. Santos; S. S. Carvalho

2006-01-01

132

Performance Evaluation of Different Twist Drills in Dry Drilling of AISI 304 Austenitic Stainless Steel  

Microsoft Academic Search

This paper evaluates the performances of HSS, K20 solid carbide and TiN – coated HSS tools in dry drilling of AISI 304 austenitic stainless steel. The roles of spindle speed, feed rate, drill point angle and number of holes on the surface roughness, tool flank wear, exit burr height and enlargement of the hole size were experimentally investigated. The structure

Ula? Çayda?; Ahmet Hasçal?k; Ömer Buytoz; Ahmet Meyveci

2011-01-01

133

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

134

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

135

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

136

Cavitation erosion resistance of AISI 316L stainless steel laser surface-modified with NiTi  

Microsoft Academic Search

The present study is part of a project on the surface modification of AISI 316 stainless steel using various forms of NiTi for enhancing cavitation erosion resistance. In this study, NiTi powder was preplaced on the AISI 316L substrate and melted with a high-power CW Nd:YAG laser. With appropriate laser processing parameters, an alloyed layer of a few hundred micrometers

K. Y. Chiu; F. T. Cheng; H. C. Man

2005-01-01

137

High-speed end-milling of AISI 304 stainless steels using new geometrically developed carbide inserts  

Microsoft Academic Search

AISI 304 stainless steel possesses some properties, such as low thermal conductivity and high ductility that make them be classified under materials of poor machinability that exhibit a lot of difficulties during cutting. This work reports an experimental study on the performance of multilayered (TiN\\/TiCN\\/TiN) carbide inserts recently developed for end-milling of AISI 304 stainless steels. The length of chip–tool

K. A. Abou-El-Hossein; Z. Yahya

2005-01-01

138

A comparison of the room-temperature behaviour of AISI 304LN stainless steel and Nimonic 90 under strain cycling  

Microsoft Academic Search

The influence of room-temperature low-cycle fatigue (LCF) deformation on the microstructure and the consequent modification of the LCF behaviour were examined in the case of AISI 304LN stainless steel and the superalloy Nimonic 90. Secondary hardening due to martensite formation in AISI 304LN enhanced its resistance to plastic flow. On the other hand, in Nimonic 90 shearing of ?? particles

S. Ganesh Sundara Raman; K. A. Padmanabhan

1995-01-01

139

The influence of Johnson–Cook material constants on finite element simulation of machining of AISI 316L steel  

Microsoft Academic Search

In literature, five different sets of work material constants used in the Johnson–Cook's (J–C) constitutive equation are implemented in a numerical model to describe the behaviour of AISI 316L steel. The aim of this research is to study the effects of five different sets of material constants of the J–C constitutive equation in finite-element modelling of orthogonal cutting of AISI

D. Umbrello; R. M’Saoubi; J. C. Outeiro

2007-01-01

140

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

141

Corrosion behaviour of aisi 304l and 316l stainless steels prepared by powder metallurgy in the presence of sulphuric and phosphoric acid  

Microsoft Academic Search

The corrosion rates of AISI 304L and 316L stainless steels prepared by powder metallurgy (P\\\\M) have been studied by continuous electrochemical methods, in different concentrations of inorganic acid solutions (sulphuric and phosphoric) at room temperature (T = 298 K). For comparison purposes, a simultaneous study was carried out on similar composition cast AISI 304L and AISI 316L stainless steels specially

E Otero; A Pardo; M. V Utrilla; E Sáenz; J. F Álvarez

1998-01-01

142

Reduction of irradiation-induced creep and swelling in AISI 316 by compositional modifications  

SciTech Connect

Studies involving high fluence irradiations of compositionally modified AISI 316 stainless steel have demonstrated that the irradiation-induced creep and swelling of this alloy can be modified through a selective choice of alloying elements. Irradiation-induced creep strain of AISI 316, is, in general, reduced by the same elements which reduce irradiation-induced swelling. It was found that the compositional dependence of both swelling and creep in this alloy system can be described through a description of the screening of dislocation strain fields. Compositional modifications which increase the mobility of the screening agents or allow the formation of more effective screeing agents will decrease the swelling and irradiation creep. This screening results in a decrease in the interstitial-dislocation bias, which results in lower swelling and in-reactor creep.

Bates, J.F.; Powell, R.W.; Gilbert, E.R.

1981-01-01

143

Effect of temperature changes on swelling and creep of AISI 316  

SciTech Connect

A number of previous publications have shown that the swelling of cold-worked AISI 316 is quite sensitive to changes in temperature which occur during irradiation. In this report those data are expanded and reanalyzed to show that the concurrent irradiation creep is also quite sensitive to changes in irradiation temperature. An explanation is advanced to explain this behavior in terms of the sensitivity to temperture history of the radiation-induced microchemical evolution of this steel. In particular, the sensitivity to temperature history of the radiation-stabilized gamma prime phase is invoked to explain the enhanced creep and swelling behavior of AISI 316 components which experienced either gradual or abrupt decreases in temperature. The phase development observed in this steel in response to temperature changes during irradiation is also compared to the similar behavior found in aged specimens subjected to isothermal irradiation.

Garner, F.A.; Gilbert, E.R.; Gelles, D.S.; Foster, J.P.

1980-04-01

144

Fluidized-bed and salt-bath heat treating (AISI 4130 and 4340 alloy steels)  

SciTech Connect

Using commercial alloy steels AISI 4130 and AISI 4340, a series of heat treating parametric studies were performed on specimens in both an electric fluidized-bed furnace and an electric neutral-salt-bath furnace. An evaluation of heat treating methods was performed by comparing tensile-test data for the two alloy steels. Surface characterization of test specimens was performed using Auger analyses to discern effects, if any, due to heat-treatment method. Certain test results are presented for two significantly different heat-treat methods and placed side by side with published mechanical test data. Environmental and safety aspects of salt-bath and fluidized-bed heat treating are discussed.

Cyrus, W.L.

1983-01-01

145

Fluidized-bed and salt-bath heat treating (AISI 4130 and 4340 alloy steels)  

SciTech Connect

Using commercial alloy steels AISI 4130 and AISI 4340, a series of heat-treating, parametric studies were performed on specimens in both an electric fluidized-bed furnace and an electric neutral salt-bath furnace. An evaluation of heat-treating methods was performed by comparing tensile test data for the two alloy steels. Surface characterization of test specimens was performed using Auger analyses to discern effects, if any, caused by the heat-treatment method. This report presents certain test results for two significantly different heat-treating methods and places them side by side with published mechanical test data. Environmental and safety aspects of salt-bath and fluidized-bed heat treating are discussed.

Cyrus, W.L.

1983-08-01

146

Prediction of Tool Wear Mechanisms in Face Milling AISI 1045 Steel  

NASA Astrophysics Data System (ADS)

Cutting tools have an important role in the machining process, since they are related to workpiece surface quality and production costs. Due to the importance of selecting appropriate cutting parameters during the milling process, this research develops empirical expressions to predict the tool wear mechanisms that a cutting tool will suffer during the milling of AISI 1045. In addition, an expression to predict the critical cutting speed value where the diffusion mechanism starts to appear is developed. AISI 1045 was selected as the workpiece material due to its excellent machinability, good abrasion resistance, and mechanical strength. The Design of Experiments method namely Taguchi was applied to reduce the time and cost of experiments. The results showed that the cutting speed is the parameter with the most influence on tool flank wear which started to appear when using V = 500 m/min and the diffusion tool wear mechanism at V = 850 m/min.

Muñoz-Escalona, Patricia; Díaz, Nayarit; Cassier, Zulay

2012-06-01

147

Determination of corrosion types for AISI type 304L stainless steel using electrochemical noise method  

Microsoft Academic Search

Electrochemical noise measurements were made on AISI type 304L SS in 0.1% NaOH, 5% H2SO4, and 0.1M FeCl3 to study passivation, uniform, and localised corrosion, respectively. Current noise and potential noise were monitored simultaneously, using a three-electrode configuration, under open circuit condition. The experiments were carried out in a closed cell at ambient temperature, without deaeration. The time records revealed

S. Girija; U. Kamachi Mudali; V. R. Raju; R. K. Dayal; H. S. Khatak; Baldev Raj

2005-01-01

148

Deformation-Induced Martensitic Transformation Behavior in Cold-Rolled AISI 304 Stainless Steels  

Microsoft Academic Search

AISI 304 stainless steels have been cold-rolled to different thickness reduction degrees, and consequently a deformation-induced martensite phase transformation takes place in the specimens. Metallurgical microscopy was used to study the microstructure and morphology of the specimens. X-ray diffraction was also used to investigate deformation-induced transformation. Martensite phase content was determined using a Ferrite Content Measuring Instrument. The evolution of

Yongfeng Li; Fuming Bu; Wenbin Kan; Hongliang Pan

2012-01-01

149

Corrosion protection of AISI 316 stainless steel by ALD alumina\\/titania nanometric coatings  

Microsoft Academic Search

Stainless steels are used today in a wide range of applications as a result of their combination of high corrosion resistance\\u000a and good mechanical properties. In some applications, for example, temporary contact biomedical devices or solar water heaters,\\u000a corrosion resistance may need further improvement, and surface coatings may be applied for enhanced protection. In this study,\\u000a AISI 316 stainless steel

E. Marin; A. Lanzutti; L. Guzman; L. Fedrizzi

150

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

151

Diffusion bonding of electroless Ni plated WC composite to Cu and AISI 316 stainless steel  

Microsoft Academic Search

In this study, a composite containing WC (Tungsten Carbide) and Ni was produced by two different processing routes. Electroless\\u000a Ni coated WC powders were consolidated and sintered at 1200 °C. Diffusion bonding couples of WC(Ni)-electrolytic Cu, WC(Ni)-AISI\\u000a 316 stainless steel and WC(Ni)-WC(Ni) were manufactured by using a preloaded compression system under Ar atmosphere. Diffusion\\u000a bonding was carried out at varying

Ahmet Yönetken; Mehmet Çakmakkaya; Ayhan Erol; ?ükrü Tala?

2011-01-01

152

Novel plasma nitriding–oxidizing duplex treatment of AISI 316 austenitic stainless steel  

Microsoft Academic Search

In this work, plasma nitriding and plasma nitriding–oxidizing treatment have been performed on AISI 316 austenitic stainless steel. In order to evaluate its response to this treatment, their microstructures and wear resistance have been compared with conventional plasma nitrided. The treatment of plasma nitriding was performed at temperature of 450°C for 5h with gas mixture of N2\\/H2:1\\/3 whereas plasma nitriding–oxidizing

H. R. Abedi; M. Salehi; M. Yazdkhasti

2010-01-01

153

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

154

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

155

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

156

Microstructure and corrosion behaviour of DC-pulsed plasma nitrided AISI 410 martensitic stainless steel  

Microsoft Academic Search

AISI 410 martensitic stainless steel samples with different metallurgical structures were DC-pulsed plasma nitrided at 623, 723 and 773 K. The samples were ion nitrided in an industrial equipment using a gas mixture consisting of 25% N2+75% H2 under a pulsed DC glow discharge. Optical and scanning electron microscopy, as well as glancing angle X-ray diffraction and microhardness measurements have

P Corengia; G Ybarra; C Moina; A Cabo; E Broitman

2004-01-01

157

Microstructural and topographical studies of DC-pulsed plasma nitrided AISI 4140 low-alloy steel  

Microsoft Academic Search

The influence of DC-pulsed plasma nitriding time on the surface properties of AISI 4140 low-alloy steel has been investigated. The samples were nitrided in an industrial equipment using a gas mixture consisting of 25% N2+75% H2 and the DC-pulsed glow discharge time was varied between 1 and 28 h. Optical and scanning electron microscopy as well as X-ray diffraction, electron

P. Corengia; G. Ybarra; C. Moina; A. Cabo; E. Broitman

2005-01-01

158

Effect of process time on structural and tribological properties of ferritic plasma nitrocarburized AISI 4140 steel  

Microsoft Academic Search

AISI 4140 steel was plasma nitrocarburized at a gas mixture of 49%N2+49%H2+2%CO2, for different process times (1, 2, 4, 8 and 12 h), at a temperature of 570 °C. The structural, mechanical and tribological properties of nitrocarburized steel were analyzed using a X-ray diffraction, microhardness tester, scanning electron microscopy, optical microscopy and pin-on-disk tribotester. The results have shown that the

Mehmet Karakan; Akgün Alsaran; Ayhan Çelik

2004-01-01

159

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

160

Competing damage mechanisms in the thermo-mechanical fatigue of AISI 304L stainless steel  

Microsoft Academic Search

Thermo-mechanical fatigue (TMF) in AISI 304L stainless steel is investigated in two temperature ranges using four phase differences between the mechanical loading and the temperature. In the temperature range from 450°C to 700°C, the fatigue life was lowest in the in-phase condition. However, in the temperature range from 400°C to 650°C, the minimum fatigue life occurs in the counter-clockwise-diamond condition.

Keun-Ho Bae; Hyun-Ho Kim; Soon-Bok Lee

2011-01-01

161

Thermal creep effects on 20% cold worked AISI 316 mechanical properties  

Microsoft Academic Search

The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977°K and stresses of 86 MPa to 276 MPa. This resulted in strains up to 1.3%. Subsequent mechanical property tests included load change stress rupture tests (original test pressure increased or decreased), uniaxial

1980-01-01

162

High Strain Rate Thermo-Inelasticity of Damaged AISI 316H  

Microsoft Academic Search

Two groups of AISI 316 H specimens, previously subjected either to creep or low cycle fatigue, are examined by tension at 550 °C in the strain-rate range [10?3, 103]s?1. The specimens previously treated by creep suffered various levels of creep strains while the specimens predamaged by LCF had various LCF strain critical cycle numbers (as a measure of initial life

C. Albertini; M. Montagnani

2003-01-01

163

In-reactor creep rupture of 20% cold-worked AISI 316 stainless steel  

Microsoft Academic Search

Results of an experiment designed to measure in-reactor stress-to-rupture properties of 20% cold-worked AISI 316 stainless steel are reported. The in-reactor rupture data are compared with postirradiation and unirradiated test results. In-reactor rupture lives were found to exceed rupture predictions of postirradiation tests. This longer in-reactor rupture life is attributed to dynamic point defect generation which is absent during postirradiation

A. J. Lovell; B. A. Chin; E. R. Gilbert

1981-01-01

164

Viscoplastic behaviour of stainless steels AISI 316L and 316H  

Microsoft Academic Search

Summary  The theory of viscoplasticity based on total strain and overstress is used in order to simulate the sensitivity to the rate\\u000a of loading of two commonly used stainless steels, namely AISI 316L and 316H. The consitutive model has been implemented within\\u000a a transient finite element computer code using a stress update algorithm based on the elastic predictor-return mapping concept.\\u000a Both

A. G. Youtsos; J. Donea; G. Verzeletti

1989-01-01

165

Optimization of cold and warm workability in stainless steel type AISI 316L using instability maps  

Microsoft Academic Search

The deformation characteristics of stainless steel type AISI 316L under compression in the temperature range 20 to 600°C and strain rate range 0.001 to 100 s?1 have been studied with a view to characterizing the flow instabilities occurring in the microstructure. At temperatures lower than 100°C and strain rates higher than 0.1 s?1 316L stainless steel exhibits flow localization whereas

S. Venugopal; S. L. Mannan; Y. V. R. K. Prasad

1995-01-01

166

Intensified plasma-assisted nitriding of AISI 316L stainless steel  

Microsoft Academic Search

In the present study, processing of AISI 316L stainless steel (316ss) has been conducted by intensified plasma-assisted processing (IPAP). The processing parameters (bias voltage, current density, chamber pressure and substrate temperature) of IPAP have been varied in an effort to determine which conditions lead to the formation of a single-phase structure, ‘m’ phase, and evaluate the properties of this phase.

V Singh; K Marchev; C. V Cooper; E. I Meletis

2002-01-01

167

Electrochemistry of AISI 316L stainless steel in calcium phosphate and protein solutions  

Microsoft Academic Search

The influence of calcium phosphate and serum on the corrosion resistance of AISI 316L stainless steel in 0.9% NaCl solution was investigated. Both substances are responsible for an increase in the pitting corrosion resistance. Calcium phosphate accelerates the rate of film formation, enhances the release of iron and nickel, and retards that of chromium from a corroding surface. Proteins induce

S. R. Sousa; M. A. Barbosa

1991-01-01

168

Economical and ecological cryogenic machining of AISI 304 austenitic stainless steel  

Microsoft Academic Search

While it is a clean alternative to conventional machining using environmentally polluting cutting oils and emulsions, cryogenic\\u000a machining using liquid nitrogen has been reported to increase cutting forces and shorten tool life when cutting AISI 304 austenitic\\u000a stainless steel. This paper presents improved results by using an economical cryogenic cooling approach designed after studying\\u000a the cryogenic properties of the stainless

Shane Y. Hong; Mark Broomer

2000-01-01

169

Carbide-reinforced coatings on AISI 316 L stainless steel by laser surface alloying  

Microsoft Academic Search

In order to improve the sliding wear resistance of stainless steel components, carbide-hardened surfaces were produced on AISI 316 L austenitic stainless steel by laser surface alloying. Cr3C2 or TiC powder was applied to the steel surface and irradiated using a continuous wave, 300 W, Nd-YAG laser.Surface alloys resulting from the incorporation of Cr3C2 were found to be composed of

C. Tassin; F. Laroudie; M. Pons; L. Lelait

1995-01-01

170

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

171

Microchemical evolution and swelling of AISI 316 irradiated in HFIR and EBR-II  

SciTech Connect

The radiation-induced evolution at 500 to 700/sup 0/C was examined for both annealed and cold-worked AISI 316 in EBR-II and HFIR. While some details of the phase evolution change in response to differences in neutron spectra, the dislocation development and the major facets of the microchemical evolution of the matrix are unchanged. Despite the increased cavity densities generated in HFIR, total swelling appears to be unaffected by increased levels of helium and solid transmutants.

Brager, H.R.; Garner, F.A.

1983-03-01

172

Microstructural and microchemical comparisons of AISI 316 irradiated in HFIR and EBR-II  

Microsoft Academic Search

This paper shows that swelling data for annealed AISI 316 provide insight concerning the role of helium on swelling. Additional insight has been obtained by a series of microstructural and microchemical examinations conducted on specimens of both annealed and cold-worked steel after irradiation in EBR-II and HFIR. At least in the range 500 to 750°C, the results of these studies

H. R. Brager; F. A. Garner

1982-01-01

173

Microchemical evolution and swelling of AISI 316 irradiated in HFIR and EBR-II  

Microsoft Academic Search

The radiation-induced evolution at 500 to 700°C was examined for both annealed and cold-worked AISI 316 in EBR-II and HFIR. While some details of the phase evolution change in response to differences in neutron spectra, the dislocation development and the major facets of the microchemical evolution of the matrix are unchanged. Despite the increased cavity densities generated in HFIR, total

H. R. Brager; F. A. Garner

1983-01-01

174

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

175

Study of the S phase formed on plasma-nitrided AISI 316L stainless steel  

Microsoft Academic Search

Some tribological and corrosion resistance properties of austenitic stainless steels are enhanced by the formation of the S phase, also called expanded austenite. This phase is formed on the surfaces of austenitic stainless steels nitrided under certain conditions. In this work, AISI 316L steel was plasma-nitrided at 350, 400, 450, and 500°C, and the samples were characterized by X-ray diffraction

L. C. Gontijo; R. Machado; E. J. Miola; L. C. Casteletti; N. G. Alcântara; P. A. P. Nascente

2006-01-01

176

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

Microsoft Academic Search

The low-temperature mechanical properties of AISI 4340 ultrahigh-strength steel can be dramatically improved by high-temperature\\u000a thermomechanical treatment (HTMT). A comparison was made with the mechanical properties developed by the conventional heat-treatment\\u000a (CHT). When the steel was hot forged by 50 pct reduction at 1177 K followed by direct oil quenching and subsequent tempering\\u000a at 423 K, the slow-bending fracture energy

Yoshiyuki Tomita

1991-01-01

177

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

178

MICROSTRUCTURAL ALTERATION AND MICROHARDNESS AT NEAR-SURFACE OF AISI H13 STEEL BY HARD MILLING  

Microsoft Academic Search

In the present research, the microstructural alteration and microhardness at near-surface of AISI H13 steel by hard milling under different cutting parameters with coated cutting tools have been investigated. Very thin white layer forms or even no obvious microstructural alteration layer appears at the near-surface. It is reasonable that the formation of the very thin white layer is primarily due

S. Zhang; T. C. Ding; J. F. Li

2012-01-01

179

Laser welding of 3 mm thick laser-cut AISI 304 stainless steel sheet  

Microsoft Academic Search

The objective of the present work was to study the laser weldability of laser-cut 3 mm thick AISI 304 austenitic stainless\\u000a steel sheet (using oxygen as an assist gas). For minimizing heat input during laser cutting, which is an important factor\\u000a influencing the thickness of the oxide layer on the cut surface, laser cutting was performed in pulsed mode. The

Harish Kumar; P. Ganesh; Rakesh Kaul; B. Tirumala Rao; Pragya Tiwari; A. K. Nath; Ranjeet Brajpuriya; S. M. Chaudhari

2006-01-01

180

Effect of superheat on the solidification structures of AISI 310S austenitic stainless steel  

Microsoft Academic Search

An experimental study was carried out to investigate the evolution of macrostructure and microstructure in AISI 310S stainless\\u000a steel during solidification. Experimental findings suggested that the macrostructure and the microstructure of the cast material\\u000a responded differently to variations in casting temperature. As the casting temperature decreased, the macro structure was\\u000a refined, as expected, but the microstructure coarsened. A relationship was

S. Ozbayraktar; A. Koursaris

1996-01-01

181

Production of nano\\/submicron grained AISI 304L stainless steel through the martensite reversion process  

Microsoft Academic Search

Production of nano\\/submicron grained AISI 304L austenitic stainless steel through formation of strain-induced martensite and its reversion to austenite are studied in this paper. The effects of annealing parameters on the microstructural development and mechanical properties are also investigated. Heavily cold rolling at 0°C is employed to induce the formation of martensite in the metastable austenitic material, followed by reversion

Farnoosh Forouzan; Abbas Najafizadeh; Ahmad Kermanpur; Ali Hedayati; Roohallah Surkialiabad

2010-01-01

182

Role of intergranular precipitation in the fracturebehaviour of aisi 316 austenitic stainless steel  

Microsoft Academic Search

Fractography of AISI 316 unstabilized austenitic stainless steels, after tensile testing,is the main topic of the present work. To characterize relationships between the steelmicrostructure, mechanical properties, and fracture mode, methods of light, scanning, andtransmission electron microscopies were used.The transgranular ductile mode was found to be dominant in fracture of the steel at 293and 923 K. Fracture surfaces of tensile samples

J. Janovec; J. Blach; P. Záhumensky; V. Magula; J. Pecha

1999-01-01

183

Behavior of sulfide inclusions during thermomechanical processing of AISI 4340 steel  

Microsoft Academic Search

The morphological and compositional modifications of sulfides in AISI 4340 low alloy steel, in which the sulfur level was\\u000a raised to about 0.1 pct, were studied during hotrolling at 1223 K followed by homogenization at 1583 K for various lengths\\u000a of time. The relative plasticity of sulfide inclusions with respect to the steel matrix increased with cooling rate during\\u000a solidification,

Y. V. Murty; T. Z. Kattamis; R. Mehrabian; M. C. Flemings

1977-01-01

184

An analysis of plastic instability in pure shear in high strength AISI 4340 steel  

Microsoft Academic Search

The phenomenon of plastic instability in pure shear was studied at room temperature in heat treated high-strength AISI 4340\\u000a steels, employing the torsion test. The instability occurs after saturation of strain hardening by the dispersed carbide particles.\\u000a The strain at onset of instability is sensitively dependent on rate of straining. The effective stress (total stress minus\\u000a the stress resulting from

Kohichi Tanaka; JOSEPH W. SPRETNAK

1973-01-01

185

The effect of step quenching on the microstructure and fracture toughness of aisi 4340 steel  

Microsoft Academic Search

The microstructure and fracture toughness of AISI 4340 steel in the direct and in the step quenched and tempered condition\\u000a has been studied. Austenitizing temperatures of 1473 K followed by step quenching to either 1373 or 1143 K prior to oil quenching\\u000a have been employed. A consistent drop in the fracture toughness values was observed as the intermediate holding temperature

Khalid H. Khan; William E. Wood

1978-01-01

186

Fracture mechanics and surface chemistry studies of subcritical crack growth in AISI 4340 steel  

Microsoft Academic Search

Coordinated fracture mechanics and surface chemistry experiments were carried out to develop further understanding of environment\\u000a enhanced subcritical crack growth in high strength steels. The kinetics of crack growth were determined for an AISI 4340 steel\\u000a (tempered at 204C) in hydrogen and in water, and the kinetics for the reactions of water with the same steel were also determined.\\u000a A

G. W. Simmons; P. S. Pao; R. P. Wei

1978-01-01

187

Stress history effect on incubation time for stress corrosion crack growth in AISI 4340 steel  

Microsoft Academic Search

The effect of stress history on stress corrosion cracking of AISI 4340 steel in an aqueous environment has been studied with\\u000a the use of double-cantilever beam specimens. The stress history effect was found to influence the incubation time period with\\u000a changes in the stress intensity. When the stress intensity was decreased, the incubation time period was dependent on the\\u000a ?K

D. L. Dull; L. Raymond

1972-01-01

188

An investigation of the plastic fracture of AISI 4340 and 18 Nickel200 grade maraging steels  

Microsoft Academic Search

The mechanisms of plastic fracture (dimpled rupture) in high-purity and commercial 18 Ni, 200 grade maraging steels and quenched\\u000a and tempered AISI 4340 steels have been studied. Plastic fracture takes place in the maraging alloys through void initiation\\u000a by fracture of titanium carbo-nitride inclusions and the growth of these voids until impingement results in coalescence and\\u000a final fracture. The fracture

T. B. Cox; J. R. Low

1974-01-01

189

Performance of laser-treated AISI-M2 cutting tools for peeling beech  

Microsoft Academic Search

For many wood machining processes, the interest of tool steels remains very important because of their\\u000a good tool edge accuracy and easy grinding. The main problem is their low resistance to wearing and corrosion.\\u000a In order to increase their performance, a laser melting and cladding applied on the tool edges is presented\\u000a in this paper. Firstly, annealed AISI-M2 bar was melted,

Wayan Darmawan; Jean Quesada; Frédérique Rossi; Rémy Marchal; Frédérique Machi; Hiroshi Usuki

2009-01-01

190

Microstructural characterization of AISI 431 martensitic stainless steel laser-deposited coatings  

Microsoft Academic Search

High cooling rates during laser cladding of stainless steels may alter the microstructure and phase constitution of the claddings\\u000a and consequently change their functional properties. In this research, solidification structures and solid state phase transformation\\u000a products in single and multi layer AISI 431 martensitic stainless steel coatings deposited by laser cladding at different\\u000a processing speeds are investigated by optical microscopy,

I. Hemmati; V. Ocelík; J. Th. M. De Hosson

2011-01-01

191

Microstructure evolution of AISI 316L in torsion at high temperature  

Microsoft Academic Search

Hot monotonic, double-deformation and reversed torsion deformation of AISI 316L stainless steel was investigated with a constant equivalent strain rate of 0.006 s?1 in the temperature range 850–1100 °C. The effect of grain size and strain rate was also investigated and compared with monotonic tension. A tendency for the grain boundaries to align with the major shear directions was found

G. Angella; B. P. Wynne; W. M. Rainforth; J. H. Beynon

2005-01-01

192

E?ects of AISI 316L corrosion products in in vitro bone formation  

Microsoft Academic Search

Rat bone marrow cells were cultured in experimental conditions that favour the proliferation and di?erentiation of osteoblastic cells (i.e., 2.52)10~4 mol l~1 ascorbic acid, 10~2 mol l~1 b-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

S. Morais; J. P. Sousa; M. H. Fernandes; G. S. Carvalho; J. D. de Bruijn; C. A. van Blitterswijk

1998-01-01

193

Effect of variable intensity ultraviolet radiation on passivity breakdown of AISI Type 304 stainless steel  

Microsoft Academic Search

The effect of ultraviolet illumination on passivity breakdown of a commercial grade (CG) of AISI Type 304 stainless steel and of a high purity heat (HPH) of the same material in neutral 0.5 M NaCl solution and in 0.025 M NaCl + 0.15 M H3BO3\\/0.007 M Na2B4O7, pH = 7.5, solution was experimentally studied. Passivity breakdown on the CG, as

Digby D. Macdonald; Donald F. Heaney

2000-01-01

194

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

195

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

SciTech Connect

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/sup -5/ to 10/sup -7/ s/sup -1/ in simulated boiling water reactor (BWR) environments that contain SO/sub 4//sup 2 -/ as an impurity. It is observed that although AISI 316 NG SS is extremely resistant to integranular SCC (IGSCC) even when subjected to severe heat treatments, it can become susceptible to transgranular SCC (TGSCC) in the presence of impurities. Sensitized AISI 316 SS, however, is susceptible to IGSCC even in high-purity water containing 0.2 ppm O/sub 2/ and the addition of an impurity aggravates the IGSCC susceptibility. The SCC results obtained for both materials are discussed in terms of a phenomenological model that incorporates a slip-dissolution mechanism and elastic-plastic fracture mechanics. The results for both IGSCC and TGSCC are demonstrated to be consistent with the slip-dissolution model of Ford.

Maiya, P.S.; Shack, W.J.

1985-11-01

196

The effect of substrate bias voltages on impact resistance of CrAlN coatings deposited by modified ion beam enhanced magnetron sputtering  

Microsoft Academic Search

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 (111), (200) (220)

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

2009-01-01

197

Correlation of substructure with mechanical properties of plastically deformed AISI 304 and 316 stainless steel. Progress report, January 1March 31, 1973  

Microsoft Academic Search

The recovery behavior of cold-worked AISI -316 stainless steel was ; studied using hot hardness. Hot hardness and substructure of AISI 304 stainless ; steel were correlated with tensile data, and transmission electron microscopy was ; carried out. The substructure of Incoloy 800 tensile tested at 800 to 1400 deg F ; was studied. (DLC)

Moteff

1973-01-01

198

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

199

Structural, mechanical, and tribological studies of Cr–Ti–Al–N coating with different chemical compositions  

Microsoft Academic Search

In this paper, a multicomponent hard coating system of Cr–Ti–Al–N has been studied for its structural, mechanical and tribological properties under different chemical compositions. The coatings were deposited onto AISI M42 steel plates by closed-field unbalanced magnetron sputtering ion plating (CFUBMSIP) technique in a gas mixture of Ar+N2. Three processing steps in deposition involved were plasma ion cleaning, buffer layer

P. L. Tam; Z. F. Zhou; P. W. Shum; K. Y. Li

2008-01-01

200

Corrosion-wear monitoring of TiN coated AISI 316 stainless steel by electrochemical noise measurements  

NASA Astrophysics Data System (ADS)

A modified electrochemical noise (EN) technique has been applied to monitor corrosion-wear of TiN coated AISI 316 stainless steel sliding against corundum in 0.5 M H2SO4. Experimental results show that the EN technique can sensitively detect potential and current variations during a corrosion-wear process. Corrosion-wear mechanisms of TiN coatings depend on their substrate properties. When the substrate is passive, such as AISI 316 stainless steel, the potential and current variations reflect the properties of coatings. Depassivation and repassivation alternately take place on the tribo-activated wear area during the steady-state phase.

Quan, Zhenlan; Wu, Pei-Qiang; Tang, Lin; Celis, J.-P.

2006-11-01

201

Microstructural origins of yield-strength changes in AISI 316 during fission or fusion irradiation  

SciTech Connect

The changes in yield strength of AISI 316 irradiated in breeder reactors have been successfully modeled in terms of concurrent changes in microstructural components. Two new insights involving the strength contributions of voids and Frank loops have been incorporated into the hardening models. Both the radiation-induced microstructure and the yield strength exhibit transients which are then followed by saturation at a level dependent on the irradiation temperature. Extrapolation to anticipated fusion behavior based on microstructural comparisons leads to the conclusion that the primary influence of transmutational differences is only to alter the transient behavior and not the saturation level of yield strength.

Garner, F.A.; Hamilton, M.L.; Panayotou, N.F.; Johnson, G.D.

1981-08-01

202

Wear behavior of AISI 1090 steel modified by pulse plasma technique  

SciTech Connect

AISI 1090 steel was pulse plasma treated (PPT) using a Molybdenum electrode. Two different pulse numbers were chosen to obtain modified layers of 20{+-}5 {mu}m thickness. The dry sliding wear studies performed on this steel with and without PPT against an alumina ball counterpart showed that the PPT improved the wear resistance. The pulse number of the PPT modified layer was found to be highly influential in imparting the wear resistance to this steel, due to enhancement of surface hardness depending on treatment time.

Ayday, Aysun; Durman, Mehmet [Sakarya University, Faculty of Engineering, Department of Metallurgical and Materials Engineering, Adapazar Latin-Small-Letter-Dotless-I , 54187 (Turkey)

2012-09-06

203

Wear behavior of AISI 1090 steel modified by pulse plasma technique  

NASA Astrophysics Data System (ADS)

AISI 1090 steel was pulse plasma treated (PPT) using a Molybdenum electrode. Two different pulse numbers were chosen to obtain modified layers of 20+/-5 ?m thickness. The dry sliding wear studies performed on this steel with and without PPT against an alumina ball counterpart showed that the PPT improved the wear resistance. The pulse number of the PPT modified layer was found to be highly influential in imparting the wear resistance to this steel, due to enhancement of surface hardness depending on treatment time.

Ayday, Aysun; Durman, Mehmet

2012-09-01

204

Corrosion behavior of AISI 316L stainless steel surface-modified with NiTi  

Microsoft Academic Search

AISI 316L stainless steel was surface-modified with NiTi using three different methods: (1) laser surface alloying using NiTi powder (LSA-NiTi-powder), (2) laser cladding using NiTi strips (LC-NiTi-strip), and (3) microwave-assisted brazing using NiTi plates (MB-NiTi-plate). These methods are capable of bringing significant improvement in the cavitation erosion resistance as reported elsewhere. The present work aims at studying the corrosion behaviors

K. Y. Chiu; F. T. Cheng; H. C. Man

2006-01-01

205

Microstructural origins of yield strength changes in AISI 316 during fission or fusion irradiation  

SciTech Connect

The changes in yield strength of AISI 316 irradiated in breeder reactors have been successfully modeled in terms of concurrent changes in microstructural components. Two new insights involving the strength contributions of voids and Frank loops have been incorporated into the hardening models. Both the radiation-induced microstructure and the yield strength exhibit transients which are then followed by saturation at a level dependent on the irradiation temperature. Extrapolation to anticipated fusion behavior based on microstructural comparisons leads to the conclusion that the primary influence of transmutational differences is only to alter the transient behavior and not the saturation level of yield strength.

Garner, F.A.; Hamilton, M.L.; Panayotou, N.F.; Johnson, G.D.

1980-01-01

206

Microchemical evolution and swelling of AISI 316 irradiated in HFIR and EBR-II  

SciTech Connect

The radiation-induced evolution at 500 to 700/sup 0/C was examined for both annealed and cold-worked AISI 316 in EBR-II and HFIR. While some details of the phase evolution change in response to differences in neutron spectra, the dislocation development and the major facets of the microchemical evolution of the matrix are unchanged. Despite the increased cavity densities generated in HFIR, total swelling appears to be unaffected by increased levels of helium and solid transmutants. 22 refs., 5 figs.

Brager, H.R.; Garner, F.A.

1983-01-01

207

Effect of shock duration on the dynamic consolidation of powders. [AISI 9310  

SciTech Connect

A recent advanced model for the shock consolidation of powders predicts, for a powder given distension, the regimes of shock pressure and shock duration expected to yield fully densified compacts of near optimum strength. The model is evaluated in terms of UTS measurements in compacts of rapidly solidified powders of AISI 9310 alloy, shocked to initial shock pressures between 3.6 and 17.9 GPa and to shock durations between 0.23 and 2.1 ..mu..s. We find that in powders of distention 1.7, shock durations > 1 ..mu..s are required at 10 GPa to properly solidify the melt.

Schwarz, R.B.; Kasiraj, P.; Vreeland, T. Jr.; Ahrens, T.J.

1983-09-01

208

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

209

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

210

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

211

Surface treatment for mitigation of hydrogen absorption and penetration into AISI 4340 steel  

SciTech Connect

The effectiveness of underpotential deposition of Pb onto a membrane made of AISI 4340 steel on the reduction of the hydrogen evolution reaction on the membrane and the degree of hydrogen ingress into the membrane was determined. In the presence of a monolayer coverage of Pb on the membrane surface, the hydrogen evolution currents were reduced by a factor of two compared with the values obtained on bare steel, and the steady-state hydrogen permeation flux through the steel membranes was reduced by 71%.

Zheng, G.; Popov, B.N.; White, R.E. (Univ. of South Carolina, Columbia SC (United States). Dept. of Chemical Engineering)

1993-11-01

212

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)

1995-11-01

213

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

SciTech Connect

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 entitled ''Temperature Measurement of Galvanneal Steel'' uses phosphor thermography, and outgrowth of Uranium enrichment research at Oak Ridge facilities. Temperature is the controlling factor regarding the distribution of iron and zinc in the galvanneal strip coating, which in turn determines the desired product properties

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

1999-06-30

214

Investigation into some tribological properties of plasma nitrided hot-worked tool steel AISI H11  

SciTech Connect

Interest in the tribological properties of plasma nitriding has increased substantially over the past years because plasma nitriding provides a high nitride depth and improved hard facing. The present study examines the tribological properties of AISI H11 plasma nitrided, hot-worked steel. Different nitriding temperatures and durations were considered. Characterization of the composite structures was investigated with wear tests, x-ray diffraction (XRD) analysis, scanning electron microscopy (SEM), and microhardness tests. The depth profile of the nitrided zone was measured using the nuclear reaction analysis (NRA) technique. Plasma nitriding affected the microhardness, wear properties, and morphology considerably. Increase in process temperature increased the nitride zone depth.

Yilbas, B.S.; Sahin, A.Z.; Said, S.A.M.; Nickel, J.; Coban, A. [King Fahd Univ. of Petroleum and Minerals, Dhahran (Saudi Arabia). Dept. of Mechanical Engineering

1996-04-01

215

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

NASA Astrophysics Data System (ADS)

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 the particles, which constitute the porous medium. Besides, the study of the relationship between physical properties, such as mass density, porosity, and permeability and the microstructure shows that the greater the particle interaction the better the thermal properties correlation.

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

2003-01-01

216

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 CO2 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

217

Hard surfacing of TiAl intermetallic compound by plasma carburization  

Microsoft Academic Search

For an intermetallic compound such as TiAl to be used in various components, the wear resistance is very important. Recently, plasma carburization was performed on the fully lamellar cast alloy with Ti-33.5Al-1Nb-0.5Cr-0.5Si (mass%). The induced surface layer, 3 ?m in thickness, was a carbide, Ti2AlC, with a hardness that was higher than HV836 for a bearing steel AISI52100. The pin-on-disk

T. Noda; M. Okabe; S. Isobe

1996-01-01

218

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

SciTech Connect

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, Jose C.; Pina, Jose C. [X-Ray Diffraction Centre for Materials Research, University of Coimbra, P-3004 516 Coimbra (Portugal); Umbrello, Domenico; Rizzuti, Stefania [Department of Mechanical Engineering, University of Calabria 87036 Rende (Italy)

2007-05-17

219

Microstructural interpretation of the fluence and temperature dependence of the mechanical properties of irradiated AISI 316  

SciTech Connect

The effects of neutron irradiation on the mechanical properties of annealed and 20% cold-worked AISI 316 irradiated in EBR-II were determined for the temperature regime of 370 to 760/sup 0/C for fluences up to 8.4 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV). At irradiation temperatures below about 500/sup 0/C, both annealed and cold-worked material exhibit a substantial increase in the flow stress with increasing fluence. Furthermore, both materials eventually exhibit the same flow stress, which is independent of fluence. At temperatures in the range of 538 to 650/sup 0/C, the cold-worked material exhibits a softening with increasing fluence. Annealed AISI 316 in this temperature regime exhibits hardening and at a fluence of 2 to 3 x 10/sup 22/ n/cm/sup 2/ (E > 0.1 MeV) reaches the same value of flow stress as the cold-worked material.

Johnson, G.D.; Garner, F.A.; Brager, H.R.; Fish, R.L.

1980-04-17

220

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

221

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

222

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

223

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

224

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

225

Effect of Electrode Coating on the High Temperature Mechanical Properties of AISI 316 Austenitic Weld Metals. Part 1.  

National Technical Information Service (NTIS)

It is generally recognized that the long term ductility of AISI 316 stainless steel weld metal is inferior to that of the parent metal but will be influenced by weld metal composition. The present work is the initial part of a broadly based investigation ...

R. G. Thomas

1977-01-01

226

Development of an irradiation creep correlation for 20% cold-worked AISI 316 in fusion environments: DAFS contribution  

SciTech Connect

A correlation has been developed describing the anticipated irradiation creep behavior of 20% cold-worked AISI 316 in fusion environments. It incorporates low temperature fast breeder and thermal reactor data to extend the existing breeder correlation to the temperature range of the proposed Fusion Energy Device. It also includes a dependence on displacement rate not currently incorporated in the corresponding breeder correlation.

Doran, D.G.

1980-01-01

227

Corrosion behavior and tensile properties of AISI 316LN stainless steel exposed to flowing sodium at 823 K  

Microsoft Academic Search

Austenitic stainless steel of the grade AISI 316 LN was exposed to flowing sodium in a loop at 823 K for 6,000 h to examine the corrosion and mass-transfer behavior. The specimens were incorporated in specially designed sample holders in the loop. These were retrieved and examined by various metallurgical techniques. Specimens were also subjected to thermal aging in the

S. Rajendran Pillai; N. Sivai Barasi; H. S. Khatak; A. L. E. Terrance; R. D. Kale; M. Rajan; K. K. Rajah

2000-01-01

228

Modeling of recrystallization and austenite grain size for AISI 316 stainless steel and its application to hot bar rolling  

Microsoft Academic Search

In this study, we have developed a model for predicting recrystallized volume fraction (RXN) and austenite grain size (AGS) of AISI 316 stainless steel by using hot torsion test and then applied it to bar rolling process. It was found that the proposed model coupled with the analytic equation for bar rolling could in a general way predict average values

Sung-Il Kim; Youngseog Lee; Byoung-Lok Jang

2003-01-01

229

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

230

An evaluation of shot peening, residual stress and stress relaxation on the fatigue life of AISI 4340 steel  

Microsoft Academic Search

Shot peening is a method widely used to improve the fatigue strength of materials, through the creation of a compressive residual stress field (CRSF) in their surface layers. In the present research the gain in fatigue life of AISI 4340 steel, used in landing gear, is evaluated under four shot peening conditions. Rotating bending fatigue tests were conducted and the

M. A. S. Torres; H. J. C. Voorwald

2002-01-01

231

Acoustic emission technique for detecting micro- and macroyielding in solution-annealed AISI Type 316 austenitic stainless steel  

Microsoft Academic Search

The acoustic emission (AE) technique has been used to detect the microplastic yielding occurring during macroscopic elastic deformation in an AISI Type 316 stainless steel. It has been observed that selection of different resonant frequency sensors is essential to detect the AE signal with maximum sensitivity at different strain levels during tensile deformation. An attempt has been made to develop

V. Moorthy; T. Jayakumar; Baldev Raj

1995-01-01

232

DAFS contribution: the influence of dislocation density and radiation on carbon activity and phase development in AISI 316. [LMFBR  

SciTech Connect

The objective of this effort is to identify the role of each major element in the microchemical evolution of AISI 316 and the dependence of that role on preirradiation treatment and parameters such as neutron energy and flux, temperature and stress.

Garner, F.A.; Wolfer, W.G.

1980-01-01

233

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

234

Modeling the reversion of martensite in the cold worked AISI 304 stainless steel by artificial neural networks  

Microsoft Academic Search

In this paper, the effect of annealing temperature and time on the reversion of strain-induced martensite to austenite in the cold worked AISI 304 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 good agreement with experimental data taken from

H. Mirzadeh; A. Najafizadeh

2009-01-01

235

Residual stress relaxation in an AISI 4140 steel due to quasistatic and cyclic loading at higher temperatures  

Microsoft Academic Search

Residual stresses can be relaxed by supplying sufficiently high amounts of thermal and\\/or mechanical energy, which converts the residual elastic strains to microplastic strains. In order to better understand this relaxation behavior, shot peening induced residual stresses in normalized condition and in quenched and tempered condition of the steel AISI 4140 (German grade 42 CrMo 4) were investigated in annealing

H. Holzapfel; V. Schulze; O. Vöhringer; E. Macherauch

1998-01-01

236

Experimental investigation on ductile stable crack growth emanating from wire-cut notch in AISI 4340 steel  

Microsoft Academic Search

An experimental investigation on the stable crack growth (SCG) behaviour in AISI 4340 using CT type specimen with a sharp slit (0.05mm) under mode I and mixed modes (I and II) loading is presented. The slit was made in the specimen through wire cutting technique. Different combinations of loading angle ? and ratio of original crack length to specimen width

A. H. I. Mourad; M. J. Alghafri; O. A. Abu Zeid; S. K. Maiti

2005-01-01

237

Influence of pulsating magnetic field on softening behaviour of cold rolled AISI 4340 steel at room temperature  

Microsoft Academic Search

Thus it may be summarised that hardness of the cold rolled AISI 4340 steel is lowered due to exposure in alternating magnetic field of 942 Oe, at room temperature. The results are discussed in terms of vibrational effect and increased mobility of dislocations and their consequent rearrangement to offer less resistance to deformation.

S. N. Prasad; P. N. Singh; Vakil Singh

1996-01-01

238

Welding procedure specification. Supplement 1. Records of procedure qualification tests. Shielded metal arc welding of AISI 4340 alloy steel  

SciTech Connect

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 (F-4, A-1).

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

1986-06-01

239

STUDY OF MATERIAL REMOVAL RATE AND ELECTRODE WEAR RATIO FOR MICRO ELECTRICAL DISCHARGE MILLING OF AISI 420 AND STAVAX ESR  

Microsoft Academic Search

This paper investigates micro electrical discharge (ED) milling for AISI 420 and Stavax ESR stainless steel using tungsten carbide electrode. For each of the materials, experiments have been conducted using the full factorial combination of gap voltage, capacitance and feed rate. Two responses material removal rate (MRR) and electrode wear ratio (EWR) are analyzed. Both MRR and EWR are found

Mohammad Yeakub Ali; Ahsan Ali Khan; Munirah Hamzah; Nor Azura Khalid

2009-01-01

240

Effect of electrical discharge machining on surface characteristics and machining damage of AISI D2 tool steel  

Microsoft Academic Search

In this work the electrical discharge machining (EDM) of AISI D2 tool steel was investigated. The surface characteristics and machining damage caused by EDM were studied in terms of machining parameters. Based on the experimental data, an empirical model of the tool steel was also proposed. A new damage variable was used to study the EDM damage. The workpiece surface

Y. H. Guu; H. Hocheng; C. Y. Chou; C. S. Deng

2003-01-01

241

Enhancement of corrosion resistance of AISI 420 stainless steels by nitrogen and silicon plasma immersion ion implantation  

Microsoft Academic Search

The effects of nitrogen and silicon plasma immersion ion implantation (PIII) on the surface corrosion resistance of martensitic stainless steel AISI 420 were investigated. Nitrogen was plasma-implanted at elevated temperature and diffused to form a thick and continuous nitrided surface layer, followed by silicon cathodic arc plasma implantation to produce an additional Si-rich oxynitride region near the stainless steel surface.

Ricky K. Y. Fu; D. L. Tang; G. J. Wan; Paul K. Chu

2007-01-01

242

Investigating the Tool Life, Cutting Force Components, and Surface Roughness of AISI 302 Stainless Steel Material Under Oblique Machining  

Microsoft Academic Search

The aim of this work is to investigate the machinability of austenitic AISI 302 stainless steel under oblique cutting. This can be achieved by studying the cutting forces, analysis of tool life, and investigation of the surface roughness at different cutting conditions and nose radius. A factorial experiment and analysis of variance technique are used in which several factors are

A. M. El-Tamimi; T. M. El-Hossainy

2008-01-01

243

Bio-Fuel-Contaminated Lubricant and Hardening Effects on the Friction and Wear of AISI 1045 Steel  

Microsoft Academic Search

A study has been made on the wear and friction of hardened AISI 1045 steel using a tri-pin-on-disc type of friction and wear apparatus. During the investigation the linear pin wear, coefficient of friction and rise in pin specimen temperature were monitored and wear and friction curves plotted. Wear surfaces and mechanisms were investigated by means of optical microscopy. Analysis

M. A. Maleque; H. H. Masjuki; M. Ishak

1998-01-01

244

Heat to Heat Variations in the Creep Rupture Strength of a Modified AISI 316 Grade Stainless Steel.  

National Technical Information Service (NTIS)

A modified AISI 316 grade stainless steel has been used as the construction material for a large number of structural and core components for the Fast Breeder Test Reactor. The creep rupture properties of this material belonging to these different heats h...

M. D. Mathew S. L. Mannan S. K. Ray P. Rodriguez

1984-01-01

245

Dry sliding wear of Ti–6Al–4V alloy as influenced by the counterface and sliding conditions  

Microsoft Academic Search

The dry sliding wear behaviour of the Ti–6Al–4V alloy sliding against itself and AISI M2 steel was investigated at different sliding velocities (between 0.3 and 0.8 m\\/s) and applied loads (between 50 and 200 N). Two wear mechanisms were identified, irrespective of the counterface and applied load: oxidation wear at the lowest sliding velocities (0.3–0.5 m\\/s) and delamination wear at

G Straffelini; A Molinari

1999-01-01

246

Residual Stresses in LENS-Deposited AISI 410 Stainless Steel Plates  

SciTech Connect

The residual stress in thin plate components deposited by the laser engineered net shaping (LENS{reg_sign}) process was investigated experimentally and numerically. Neutron diffraction mapping was used to characterize the residual stress in LENS-deposited AISI 410 stainless steel thin wall plates. Using the commercial welding software SYSWELD, a thermo-mechanical three-dimensional finite element model was developed, which considers also the effect of metallurgical phase transformations. The model was employed to predict the temperature history and the residual stress field during the LENS process. Several simulations were performed with the geometry and process parameters that were used to build the experimental samples. The origin of the residual stress distribution is discussed based on the thermal histories of the samples, and the modeling results are compared with measurements obtained by neutron diffraction mapping.

Wang, L [Mississippi State University (MSU); Felicellli, S D [Mississippi State University (MSU); Pratt, Phillip R [ORNL

2008-01-01

247

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

248

Thermal creep effects on 20% cold worked AISI 316 mechanical properties  

SciTech Connect

The effects of thermal creep on subsequent mechanical properties of 20% cold worked AISI 316 pressurized tubes were investigated. Specimens were subjected to temperatures of 811 to 977/sup 0/K and stresses of 86 MPa to 276 MPa. This resulted in strains up to 1.3%. Subsequent mechanical property tests included load change stress rupture tests (original test pressure increased or decreased), uniaxial tensile tests, and temperature ramp burst tests. Load change stress rupture tests were consistent with predictions from isobaric tests, and thus, consistent with the linear life fraction rule. Tests with large stress increases and tests at 866/sup 0/K displayed a tendency for earlier than predicted failure. Tensile and temperature ramp burst tests had only slight effects on material properties (property changes were attributed to thermal recovery). The test results showed that, under the conditions of investigation, dislocation structure recovery was the most significant effect of creep. 9 figures, 5 tables.

Duncan, D.R.

1980-09-01

249

Irradiation creep and embrittlement behavior of AISI 316 stainless steel at very high neutron fluences  

SciTech Connect

The irradiation-induced creep and swelling of AISI 316 stainless steel have been investigated at two temperatures (400 and 550/degree/C) to very high neutron fluences. It is shown that creep and swelling can be considered as interactive phenomena with several stages of creep related to the total amount of accumulated swelling. The final stage involves the apparent cessation of creep and has been observed only at the higher irradiation temperature. The development of a coincident and severe ex-reactor embrittlement problem after irradiation at 400/degree/C appears also to be separately related to the development of substantial swelling. This latter phenomenon was not observed at 550/degree/C. The mechanisms thought to be possibly responsible for each of these two phenomena are discussed in detail. 29 refs., 9 figs.

Porter, D.L.; Garner, F.A.

1988-02-01

250

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

251

Strength and toughness of aisi 304 and 316 at 4 K  

NASA Astrophysics Data System (ADS)

Structural design of superconducting magnets in fusion energy devices requires reliable property data at 4 K. Nitrogen-strengthened AISI 304 and 316 stainless steels are considered to be the best currently available low temperature structural alloys on the basis of their fabricability and their potential to meet the US fusion research goals of combined 1000 MPa yield strength and 200 MPa m1/2 fracture toughness at 4 K. This paper presents provisional equations for the yield strength of 304-and 316-type alloys at 4 K as a function of N content and grain size. Provisional equations for the 4 K fracture toughness, KIc(J), of these alloys are presented, in which the effects of yield strength, Ni and Mn content, and inclusion spacing are expressed quantitatively. The equations result from regression analyses of a matrix of NBS measurements that includes more extensive numerical data on alloying, refining, and processing parameters than have previously been available.

Simon, N. J.; Reed, R. P.

1986-11-01

252

Dimensional change correlations for 20% cold-worked AISI 316 stainless steel for fusion applications  

SciTech Connect

Correlations developed for void swelling and irradiation creep often arise from two separate data bases and sometimes are not well-matched, reflecting apparently minor but actually significant differences in environmental history. Previously published correlations are very empirical in nature and reflect prevailing misconceptions about the parametric sensitivity of swelling and irradiation creep. In this study a well-defined data base for swelling of 20% cold-worked AISI 316 is used in conjunction with the latest insights on swelling and creep to develop two matched dimensional change correlations for temperatures in the range of 300 to 650/sup 0/C. The new creep model, in particular, is much simpler than the complicated empirical correlation published earlier for this steel. 18 refs., 6 figs.

Clark, R.W.; Kumar, A.S.; Garner, F.A.

1987-11-01

253

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

254

Experiments on the ratchetting behavior of AISI 316L (N) austenitic steel at room temperature  

SciTech Connect

Uniaxial tension-compression ratchetting tests were performed on AISI 316 L(N) austenitic stainless steel at room temperature. The mean stresses were low in comparison to the stress amplitudes. Nevertheless, they have been found to be of major importance to strain accumulation. Also, the stress amplitude exerts a distinct but, under the given conditions, smaller influence. No plastic shakedown has been found in the tests with constant mean stress and stress amplitude. Tests with an increase in the maximum load after a number of cycles, due to an increase in mean stress or stress amplitude, show a behavior similar to that in tests performed with the higher load only. Tests with a decrease in maximum load exhibit immediate shakedown, although tests performed with only the lower load showed ratchetting.

Haupt, A. [Kernforschungszentrum Karlsruhe (Germany). Inst. fuer Materialforschung II; Schinke, B. [Fachhochschule fuer Technik Mannheim (Germany)

1996-07-01

255

Effect of Starch Binders in Alumina Coatings on Aisi 316 L Stainless Steel for Medical Application  

NASA Astrophysics Data System (ADS)

A slurry immersion technique of alumina coatings was carried out on several AISI 316 L stainless steels using two types of binding agents; commercial starch and Sarawakian starch (sago), which were also mixed with polyvinylchloride (PVA) for strengthening purposes. The sintering temperatures in this work were varied from 500 to 1000°C. Prior to sintering process, all stainless steels were metallographically ground and polished to approximately 0.6 µm of average roughness. Detailed characterisations on the sintered specimens were carried out with the aid of the secondary electron microscopy (SEM), microhardness and a profilometer. The results revealed that coated steels using sago binder showed improved adhesion and homogenous microstructures with greater hardness of 2642 HV than those found in coated steel with commercial starch after sintering process.

Ghazali, M. J.; Pauzi, A. A.; Azhari, C. H.; Ghani, J. A.; Sulong, A. B.; Mustafa, R.

256

Microstructural characterization of the HAZ in AISI 444 ferritic stainless steel welds  

SciTech Connect

Ferritic stainless steel is used as a coating for equipment in the petroleum refining industry. Welding is the main manufacturing and maintenance process used. However, little information on the metallurgical alterations caused by welding of these steels is found in the literature, prompting this study. In this study the authors evaluated the HAZ microstructure of AISI 444 ferritic stainless steel welded plates, by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The results indicated that a weld thermal cycle caused microphase precipitation in the HAZ of the ferritic stainless steel. Also needle-like Laves phase precipitation occurred in the HAZ, near the partially-melted zone. Other secondary phases such as chi and sigma were observed, as well as nitride, carbide and carbonitride precipitates.

Silva, Cleiton C. [Federal University of Ceara, Department of Materials and Metallurgical Engineering, Welding Engineering Laboratory, Campus do Pici, Building 715, CEP 60455-760, Fortaleza, Ceara (Brazil)], E-mail: cleitonufc@yahoo.com.br; Farias, Jesualdo P.; Miranda, Helio C.; Guimaraes, Rodrigo F. [Federal University of Ceara, Department of Materials and Metallurgical Engineering, Welding Engineering Laboratory, Campus do Pici, Building 715, CEP 60455-760, Fortaleza, Ceara (Brazil); Menezes, John W.A. [Federal University of Ceara, Department of Materials and Metallurgical Engineering, Materials Characterization Laboratory, Campus do Pici, Building 720, CEP 60455-760, Fortaleza, Ceara (Brazil); Neto, Moises A.M. [Federal University of Santa Catarina, Department of Mechanical Engineering, POLO-Laboratorios de Pesquisa em Refrigeracao e Termofisica, Florianopolis, Santa Catarina (Brazil)

2008-05-15

257

A New Continuous Cooling Transformation Diagram for AISI M4 High-Speed Tool Steel  

NASA Astrophysics Data System (ADS)

The increasing evolution of dilatometric techniques now allows for the identification of structural transformations with very low signal. The use of dilatometric techniques coupled with more common techniques, such as metallographic, hardness testing, and x-ray diffraction allows to plot a new CCT diagram for AISI M4 high-speed tool steel. This diagram is useful for a better selection of alternate solutions, hardening, and tempering heat treatments. More accurate determination of the various fields of transformation of austenite during its cooling was made. The precipitation of carbides highlighted at high temperature is at the origin of the martrensitic transformation into two stages (splitting phenomena). For slow cooling rates, it was possible to highlight the ferritic, pearlitic, and bainitic transformation.

Briki, Jalel; Ben Slima, Souad

2008-12-01

258

Laser welding of 3 mm thick laser-cut AISI 304 stainless steel sheet  

NASA Astrophysics Data System (ADS)

The objective of the present work was to study the laser weldability of laser-cut 3 mm thick AISI 304 austenitic stainless steel sheet (using oxygen as an assist gas). For minimizing heat input during laser cutting, which is an important factor influencing the thickness of the oxide layer on the cut surface, laser cutting was performed in pulsed mode. The results of the study demonstrated that although the laser welding of laser-cut specimens did not result in the formation of weld defects, the resultant laser weldments exhibited reduced ductility with respect to base metal and bead-on-plate laser weldments. Laser-cut and laser-welded specimens also displayed higher notch sensitivity than the base metal. However, laser-cut and laser-welded specimens still possessed enough ductility to pass guided bend tests.

Kumar, Harish; Ganesh, P.; Kaul, Rakesh; Rao, B. Tirumala; Tiwari, Pragya; Nath, A. K.; Brajpuriya, Ranjeet; Chaudhari, S. M.

2006-02-01

259

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

260

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

261

Enviromechanical testing of AISI 1020 steel in Hanford Grande Ronde groundwater  

SciTech Connect

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{sup {minus}4}/s. At a strain rate of 2 {times} 10{sup {minus}7}/s, and in highly strained regions of the specimen, evidence of EAC was observed. The SSR data are only used to assess relative, EAC susceptibility of candidate canister materials and cannot be used for quantitative prediction of materials behavior. 9 refs., 15 figs., 5 tabs.

Pitman, S.G.; Westerman, R.E. (Pacific Northwest Lab., Richland, WA (USA)); Fish, R.L. (Rockwell International Corp., Richland, WA (USA). Rockwell Hanford Operations)

1983-07-01

262

Effect of Sulfur and Zirconium on the Machinability and Mechanical Properties of AISI 1045 Steels  

NASA Astrophysics Data System (ADS)

The effects of small increases of sulfur and addition of zirconium in conjunction with sulfur on the machinability and mechanical properties of laboratory-produced AISI 1045 steels have been investigated. Machinability was measured in terms of cutting energy per unit volume of metal machined. With increasing sulfur, there is a linear increase in sulfide volume fraction and improvement in machinability. Ductility parameters such as tensile reduction in area and impact shelf energy, however, significantly decrease with sulfur, particularly in the transverse direction. Addition of zirconium causes formation of manganese-zirconium sulfides and increased globularity. Although further improvement in machinability by zirconium addition is not evident, there is a significant improvement in transverse impact properties by zirconium addition for steels containing high sulfur. The study suggests that an optimum combination of higher sulfur for improved machinability and zironium for better impact properties yields a steel with acceptable machining and ductility criteria.

Bhattacharya, Debanshu

1981-06-01

263

CEMS Study of Stainless Steel Films Deposited by Pulsed Laser Ablation of AISI316  

NASA Astrophysics Data System (ADS)

Thin stainless steel films deposited on SiO2/Si wafer were prepared by a pulsed laser ablation of austenite stainless steel (AISI316), and characterized by conversion electron Mössbauer spectrometry (CEMS) using a He gas proportional counter. As-deposited films were composed of a magnetic phase. When deposited films were heated in air at various temperatures, the hyperfine field of the magnetic phase increased. Hematite was produced on the surface, and the magnetic orientation changed from parallel to in-plane at random with the increase of heating temperatures. The metallic iron and magnetite were produced at 400°C in dry Ar + 5%H2 atmosphere. When the film was heated in wet Ar + 5%H2 atmosphere at 600°C, maghemite was produced on the surface, and austenite phase was produced in the inner film.

Nomura, K.; Yamada, Y.; Tomita, R.; Yajima, T.; Shimizu, K.; Mashlan, M.

2005-07-01

264

Surface nanocrystallization by surface mechanical attrition treatment and its effect on structure and properties of plasma nitrided AISI 321 stainless steel  

Microsoft Academic Search

A plastic deformation surface layer with nanocrystalline grains was produced on AISI 321 austenitic stainless steel by means of surface mechanical attrition treatment (SMAT). Low-temperature nitriding of SMAT and un-SMAT AISI 321 stainless steel was carried out in pulsed-DC glow discharge. The effect of SMAT pretreatment on the microstructure and properties of the stainless steel were investigated using X-ray diffraction,

Yimin Lin; Jian Lu; Liping Wang; Tao Xu; Qunji Xue

2006-01-01

265

Performance Degradation of TiN-and TiC-deposited AISI316 bipolar plates for proton exchange membrane fuel cells  

Microsoft Academic Search

TiN and TiC were deposited on AISI316 bipolar plates for proton exchange membrane fuel cells (PEMFCs) and their effects on\\u000a the corrosion resistance and overall cell performance were investigated. TiN with a Ti interlayer and TiC with a Ti interlayer\\u000a were deposited on AISI316 bipolar plates by hollow cathode discharge (HCD) ion plating. The electrochemical behavior of the\\u000a metallic bipolar

Hee Yeol Lee; Jae Woong Choi; Gil Ho Hwang; Sung Goon Kang

2006-01-01

266

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

267

Microstructural interpretation of the fluence and temperature dependence of the mechanical properties of irradiated AISI 316. [Neutron irradiation  

SciTech Connect

The effects of neutron irradiation on the mechanical properties of annealed and 20 perecent cold-worked AISI 316 irradiated in the experimental breeder reactor II were determined for the temperature regime of 370 to 760 degree C for fluences up to 8.4 X 10/sup 22/ neutrons (n)/cm/sup 2/ (E>0.1 MeV). Observations are explained in terms of the fluence and temperature dependence of the irradiation-induced microstructure. Very good agreement between the observed data and calculated strengths was obtained for both solution-annealed and cold-worked AISI 316 through the use of simple hardening expressions for each type of microstructural defect.

Johnson, G.D.; Garner, F.A.; Brager, H.R.; Fish, R.L.

1981-01-01

268

Corrosion behavior of plasma sprayed hydroxyapatite and hydroxyapatite-silicon oxide coatings on AISI 304 for biomedical application  

NASA Astrophysics Data System (ADS)

The objective of this study is to evaluate corrosion resistance of plasma sprayed hydroxyapatite (HA) and HAsbnd silicon oxide (SiO2) coated AISI 304 substrates. In HAsbnd SiO2 coatings, 10 wt% SiO2 and 20 wt% SiO2 was mixed with HA. The feedstock and coatings were characterized by X-ray diffraction and scanning electron microscopy/energy dispersive X-ray spectroscopy. The corrosion resistance was determined for the uncoated and coated samples. The corrosion resistance of the AISI 304 was found more after the deposition of the HAsbnd SiO2 coatings rather than HA coating and uncoated. All the coatings were crack free after 24 h dipping in Ringer's solution for electrochemical corrosion testing.

Singh, Gurpreet; Singh, Hazoor; Sidhu, Buta Singh

2013-11-01

269

Fatigue life prediction of GTA welded AISI 304L cruciform joints with lack of penetration using local-stress approach  

Microsoft Academic Search

The influence of welding procedure on fatigue properties of gas tungsten arc welded (GTAW) AISI 304L load carrying cruciform joints, containing lack of penetration (LOP) has been studied using a crack initiation–propagation (I-P) method. The crack process normally comprises two major phases: (1) the crack initiation life (NI): and (2) the crack propagation life (Np). The local stress-life approach is

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

2003-01-01

270

Fatigue life prediction of gas tungsten arc welded AISI 304L cruciform joints with different LOP sizes  

Microsoft Academic Search

Fatigue life evaluations have been carried out on gas tungsten arc welded (GTAW) load-carrying cruciform joints of AISI 304L stainless steel with lack of penetration (LOP) using conventional S-N and crack initiation-propagation (I-P) methods. The crack process normally comprises two major phases: (1) the crack initiation life (Ni): and (2) the crack propagation life (Np). The local stress-life approach is

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

2003-01-01

271

Laser surface coating of Fe–Cr–Mo–Y–B–C bulk metallic glass composition on AISI 4140 steel  

Microsoft Academic Search

Fe-based bulk metallic glasses exhibit very high hardness, elastic modulus\\/limit and wear\\/corrosion resistance. In the present investigation, an attempt has been made to develop an amorphous coating with Fe48Cr15Mo14Y2C15B6 bulk metallic glass on AISI 4140 substrate by laser surface processing. Following coating, the microstructure and phase aggregate were analyzed by scanning electron microscope and X-ray diffraction, respectively. Microhardness and wear

A. Basu; A. N. Samant; S. P. Harimkar; J. Dutta Majumdar; I. Manna; Narendra B. Dahotre

2008-01-01

272

Passivity and pitting of austenic stainless steel AISI 316 in the CH 3 OHH 2 SO 4 system  

Microsoft Academic Search

The passivity and pitting behaviour of AISI 316 stainless steel in methanol containing different concentrations (0.001 to 1 M) of H2SO4 has been investigated by an electrochemical method. Higher concentrations of sulphuric acid have been found to facilitate the passivation process and influence the passivity current and passivation range. The studies reveal the peculiarities of steel pitting and predicts the

V. K. Singh; V. B. Singh

1990-01-01

273

Study of mechanical properties of AISI 316 stainless steel processed by “selective laser melting”, following different manufacturing strategies  

Microsoft Academic Search

Considering additive manufacturing (AM) as a field of major interest, this paper is focused on the study of the mechanical\\u000a properties and their variability with manufacturing orientation (anisotropy) for a metallic alloy manufactured by AM, using\\u000a the technology of selective laser melting (SLM). This study has been performed on an austenitic stainless steel—AISI 316 L—used\\u000a for many industrial fields as chemical,

Itziar Tolosa; Fermín Garciandía; Fidel Zubiri; Fidel Zapirain; Aritz Esnaola

2010-01-01

274

Corrosion behavior and tensile properties of AISI 316LN stainless steel exposed to flowing sodium at 823 K  

Microsoft Academic Search

Austenitic stainless steel of the grade AISI 316 LN was exposed to flowing sodium in a loop at 823 K for 6,000 h to examine\\u000a the corrosion and mass-transfer behavior. The specimens were incorporated in specially designed sample holders in the loop.\\u000a These were retrieved and examined by various metallurgical techniques. Specimens were also subjected to thermal aging in the

S. Rajendran Pillai; N. Sivai Barasi; H. S. Khatak; A. L. E. Terrance; R. D. Kale; M. Rajan; K. K. Rajah

2000-01-01

275

Corrosion-wear monitoring of TiN coated AISI 316 stainless steel by electrochemical noise measurements  

Microsoft Academic Search

A modified electrochemical noise (EN) technique has been applied to monitor corrosion-wear of TiN coated AISI 316 stainless steel sliding against corundum in 0.5M H2SO4. Experimental results show that the EN technique can sensitively detect potential and current variations during a corrosion-wear process. Corrosion-wear mechanisms of TiN coatings depend on their substrate properties. When the substrate is passive, such as

Zhenlan Quan; Pei-Qiang Wu; Lin Tang; J.-P. Celis

2006-01-01

276

Effect of high temperature post-oxidizing on tribological and corrosion behavior of plasma nitrided AISI 316 austenitic stainless steel  

Microsoft Academic Search

In this research, the microstructure, tribological and corrosion properties of plasma nitrided-oxidized AISI 316 austenitic stainless steel at high oxidation temperature were studied and compared with conventional plasma nitride. The structural, tribological and corrosion properties were analyzed using XRD, SEM, microhardness testing, pin-on-disk tribotesting and electrochemical polarization. Plasma nitriding was conducted for 5 h at 450 °C with gas mixture of N2\\/H2 = 1\\/3

H. R. Abedi; M. Salehi; M. Yazdkhasti; A. Hemmasian-E

2010-01-01

277

Microstructure and tensile properties of AISI 316 stainless steel electron-beam cladded on C40 mild steel  

Microsoft Academic Search

A 60 kV electron-beam equipment was used to clad an AISI 316 stainless steel plate on C40 plain carbon steel. A homogeneous coating of stainless steel was obtained. The microstructure of the clad layer consisted of delta-ferrite, austenite, M6C carbide and martensite twinned on 112 crystal faces. The austenite has a heavily dislocated substructure and is characterized by intrinsic stacking

S. Tosto; F. Nenci; Hu Jiandong

1994-01-01

278

Effect of Condition of Recrystallization Heat Treatment on High-Temperature Mechanical Properties of an Irradiated AISI 316 Austenitic Steel  

Microsoft Academic Search

A study was made of the effects brought upon the radiation-induced high-temperature embrittlement of AISI 316 austenitic steel by different conditions to the specimens to produce recrystallization.Cold worked specimens were recrystallized at temperatures 950°–1,100°C held for periods ranging 2~60 min. The specimens were then irradiated to 1.7×10nvt(< MeV) at 55°C after which they were subjected to tensile testing at 650°C.In

Satoru KAWASAKI; Akimichi HISHINUMA

1974-01-01

279

A preliminary study of laser cladding of AISI 316 stainless steel using preplaced NiTi wire  

Microsoft Academic Search

NiTi wire of diameter 1mm was preplaced on AISI 316 stainless steel samples by using a binder. Melting of the NiTi wire to form a clad track on the steel substrate was achieved by means of a high-power CW Nd:YAG laser using different processing parameters. The geometry and microstructure of the clad deposit were studied by optical microscopy and scanning

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

2004-01-01

280

Enhancement of adhesion strength between two AISI 316 L stainless steel plates through atmospheric pressure plasma treatment  

Microsoft Academic Search

The adhesion between AISI 316 L stainless steel plates was studied using a poly(pyromellitic dianhydride-co-4,4?-oxydianiline), amic acid as adhesive. The surfaces of two 316 L stainless steel plates were pre-treated using an atmospheric pressure plasma to improve the surface properties before adhesion tests. The surface free energies of the stainless steel plates were improved with plasma treatment and the optimum

Shen Tang; Na Lu; Sung-Woon Myung; Ho-Suk Choi

2006-01-01

281

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

Microsoft Academic Search

Plasma nitriding experiments were carried out with DC-pulsed plasma in 25% N2+75% H2 atmosphere at low temperature (350°C) and normal temperature (550°C) for 15h. 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

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

2008-01-01

282

Friction and rolling–sliding wear of DC-pulsed plasma nitrided AISI 410 martensitic stainless steel  

Microsoft Academic Search

In the present work, industrial-scale DC-pulsed plasma nitriding for 20h at 673K was used to improve the wear resistance of an AISI 410 martensitic stainless steel. The tribological behaviour was studied and compared to the behaviour of the same steel in as-received condition.Pin-on-disc dry tests, using an alumina ball as counter-body, were carried out to determine the evolution of the

P. Corengia; F. Walther; G. Ybarra; S. Sommadossi; R. Corbari; E. Broitman

2006-01-01

283

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

284

Surface roughness and wettability of AISI 316L induced by surface mechanical attrition treatment with different milling ball diameter  

Microsoft Academic Search

Surface roughness and wettability determines the rate and quality of protein adsorption and cells adhesion on biomaterial. For this case, a rough- and hydrophilic-surface are preferable rather than a smooth- and hydrophobic-one. This paper discusses the effect of milling ball diameter used in surface mechanical attrition treatment (SMAT) on the roughness and wettability of AISI 316L. All samples were treated

B. Arifvianto; Suyitno

2009-01-01

285

An electrochemical noise study of tribocorrosion processes of AISI 304 L in Cl and SO_{4}^{2-} media  

Microsoft Academic Search

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

A. Berradja; D. Déforge; R. P. Nogueira; P. Ponthiaux; F. Wenger; J.-P. Celis

2006-01-01

286

Methodology for optimizing the electropolishing of stainless steel AISI 316L combining criteria of surface finish and dimensional precision  

Microsoft Academic Search

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)

E. Garci´a-Plaza; A. R. Marti´n; R. Trujillo; C. De la Cruz

2009-01-01

287

Methodology for optimizing the electropolishing of stainless steel AISI 316L combining criteria of surface finish and dimensional precision  

Microsoft Academic Search

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 (DeltaRa)

P. J. Núñez; E. García-Plaza; A. R. Martín; R. Trujillo; C. de La Cruz

2009-01-01

288

The electrochemical polishing behavior of porous austenitic stainless steel (AISI 316L) in phosphoric-sulfuric mixed acids  

Microsoft Academic Search

The electrochemical polishing of porous austenitic stainless steel (PASS), AISI 316L, in the phosphoric-sulfuric mixed acid with volume-ratio of 1:1, 2:1 and 3:1 at temperature ranging from 60 to 80 °C was studied. Electrochemical polishing of PASS was performed in the potential located in the limiting-current plateau of its anodic polarization curve using a rotating cylinder electrode (RCE). The results

S. C. Chen; G. C. Tu; C. A. Huang

2005-01-01

289

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

290

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

291

Strain-rate effects on the mechanical behavior of the AISI 300 series of austenitic stainless steel under cryogenic environments  

Microsoft Academic Search

A series of uni-axial tensile tests were carried out under various low temperatures and strain-rate ranges for AISI 300 austenitic stainless steel. The strain-rate dependencies of the materials under investigation were evaluated at temperatures ranging from ambient to cryogenic. Non-linear mechanical behavior such as phase transformation, discontinuous yielding and micro-damage of four kinds of commercial stainless steel-based material were quantitatively

Woong Sup Park; Seong Won Yoo; Myung Hyun Kim; Jae Myung Lee

2010-01-01

292

Corrosion resistance and hemocompatibility of multilayered Ti\\/TiN-coated surgical AISI 316L stainless steel  

Microsoft Academic Search

Ti\\/TiN-multilayered films were prepared on surgical AISI316L stainless steel by arc ion plating. The crystallographic orientation and surface morphology were studied using XRD and SEM. The corrosion resistance of the coated specimen was evaluated by open-circuit test and potentiodynamic polarization test. It was found that the multilayered Ti\\/TiN-coated specimen had a weaker tendency towards corrosion and higher corrosion resistance in

Liu Chenglong; Yang Dazhi; Lin Guoqiang; Qi Min

2005-01-01

293

SIMS analysis of hydrogen content in near surface layers of AISI 316L SS after electrolytic polishing under different conditions  

Microsoft Academic Search

Hydrogen concentration in AISI 316L stainless steel samples was monitored perpendicularly to the flat sample surface up to the depth of 0.8?m, using secondary ion mass spectrometry (SIMS). Depth profile analysis was performed on the samples after electrolytic polishing under different conditions. Analyses were performed on SAJW-05 apparatus with quadrupole Balzers QMA-410 analyzer and Physical Electronics 06-350E ion gun. 5keV

Tadeusz Hryniewicz; Piotr Konarski; Krzysztof Rokosz; Ryszard Rokicki

2011-01-01

294

Depassivation and repassivation of AISI321 stainless steel surface during solid particle impact in 10% H 2SO 4 solution  

Microsoft Academic Search

Erosion-corrosion experiments on AISI321 stainless steel in 10 wt.% H2SO4 + 15 wt.% corundum sand were carried out by means of a rotating system with the specimen on the edge of a disc. Dynamic polarization curves during erosion-corrosion were measured at different rotating rates and the weight-loss kinetics was studied at different applied potentials and rotating rates. The straining electrode

J. Li; Y. G. Zheng; J. Q. Wang; Z. M. Yao; Z. F. Wang; W. Ke

1995-01-01

295

Effect of structure evolution induced by ultrasonic peening on the corrosion behavior of AISI321 stainless steel  

Microsoft Academic Search

A nanocrystalline surface layer was produced on an AISI-321 stainless steel by severe plastic deformation via ultrasonic peening (UP). The microstructural evolution of the surface layer was characterized by means of X-ray diffraction (XRD) analysis and transmission electron microscopy (TEM). The volume fraction of strain-induced ?-martensite as a function of the effective strain (e¯) was evaluated quantitatively using XRD and

B. N. Mordyuk; G. I. Prokopenko; M. A. Vasylyev; M. O. Iefimov

2007-01-01

296

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

297

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

Microsoft Academic Search

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 °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

M. Karimi; A. Najafizadeh; A. Kermanpur; M. Eskandari

2009-01-01

298

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

299

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

300

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

301

Effect of hydrogen on fracture of U-notched bend specimens of quenched and tempered AISI 4340 steel  

Microsoft Academic Search

U-notched bend specimens of quenched and tempered AISI 4340 steel were deformed in the uncharged condition and after either\\u000a precharging or dynamically charging with hydrogen. In the uncharged condition fracture initiated at the notch surface and\\u000a progressed in mode II along a characteristic slip trace. For precharged specimens, strain to fracture was markedly reduced,\\u000a cracks nucleated internally in a mode

T. D. Lee; T. Goldenberg; J. P. Hirth

1979-01-01

302

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

303

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

304

Influence of austenitizing temperature on microstructure and mechanical properties of AISI 431 martensitic stainless steel electron beam welds  

Microsoft Academic Search

The relative effects of various austenitizing temperatures on microstructure and mechanical properties of electron beam welds of AISI 431martensitic stainless steel were studied. The post-weld heat treatments consist of austenitizing the weld samples for 1h at various temperatures, i.e., at 950°C, 1000°C, 1050°C, 1100°C and at 1150°C and air cooling followed by double tempering, i.e., tempering at 670+600°C. In the

A. Rajasekhar; G. Madhusudhan Reddy; T. Mohandas; V. S. R. Murti

2009-01-01

305

The effect of cladding speed on phase constitution and properties of AISI 431 stainless steel laser deposited coatings  

Microsoft Academic Search

Shorter processing time has given impetus to laser cladding technology and therefore in this research the AISI 431 martensitic stainless steel coatings are laser deposited at high cladding speeds, i.e. up to 117mm\\/s. The analysis of phase constitution and functional properties of the coatings are performed by optical microscopy, Scanning Electron Microscopy (SEM), and hardness and sliding wear tests. The

I. Hemmati; V. Ocelík; J. Th. M. De Hosson

2011-01-01

306

Effect of Pre-Oxidation at 800 °C on the Pitting Corrosion Resistance of the AISI 316L Stainless Steel  

Microsoft Academic Search

In situ X-ray diffraction was used to identify the oxides formed on the AISI 316L (containing 2% Mo) stainless steel during\\u000a isothermal oxidation at 800 °C, in air. Good oxidation behavior was observed on this steel when considering kinetics, structural\\u000a characteristics and scale adherence. It was demonstrated that molybdenum plays a protective role in that it hinders the outward\\u000a iron diffusion

H. Buscail; S. El Messki; F. Riffard; S. Perrier; C. Issartel

2011-01-01

307

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

308

Effects of solution heat treatment on grain growth and degree of sensitization of AISI 321 austenitic stainless steel  

Microsoft Academic Search

This work investigates the influence of solution temperature on grain growth and degree of sensitization of AISI 321 steel.\\u000a Samples were solution treated at temperatures between 800 and 1,200C for 80 min and sensitized at 600C for 105 h. Optical\\u000a microscopy and double loop electrochemical potentiodynamic reactivation (DLEPR) techniques were used to characterize and evaluate\\u000a the degree of sensitization. The

Regina Célia de Sousa; José Carlos Cardoso Filho; Auro Atsushi Tanaka; Ayana Cristina S. de Oliveira; Wilman Eduardo Italiano Ferreira

2006-01-01

309

Quantitative Evaluation of Aged AISI 316L Stainless Steel Sensitization to Intergranular Corrosion: Comparison Between Microstructural Electrochemical and Analytical Methods  

Microsoft Academic Search

The evaluation of the degree of sensitization (DOS) to intergranular corrosion (IGC) of a commercial AISI 316L austenitic\\u000a stainless steel aged at temperatures ranging from 550 °C to 800 °C during 100 to 80,000 hours was carried out using three\\u000a different assessment methods. (1) The microstructural method coupled with the Strauss standard test (ASTM A262). This method\\u000a establishes the kinetics of

H. Sidhom; T. Amadou; H. Sahlaoui; C. Braham

2007-01-01

310

Effect of thermal aging on the room temperature tensile properties of AISI type 316LN stainless steel  

Microsoft Academic Search

Round tensile specimens of AISI type 316LN stainless steel, thermally aged at 1123 K for 0, 2, 10, 25, 100, 500 and 1000 h, were tested for tensile properties at room temperature at a strain rate of 7.7×10?3 s?1. The changes in tensile properties were correlated to the transmission electron microscopic studies. The various stages of nitrogen repartitioning including Cr–N

P. Shankar; H Shaikh; S Sivakumar; S Venugopal; D Sundararaman; H. S Khatak

1999-01-01

311

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

312

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

313

Sliding friction and wear performance of Ti 6Al 4V in the presence of surface-capped copper nanoclusters lubricant  

Microsoft Academic Search

The friction and wear properties of Ti6Al4V sliding against AISI52100 steel ball under different lubricative media of surface-capped copper nanoclusters lubricant—Cu nanoparticles capped with O,O?-di-n-octyldithiophosphate (Cu-DTP), rapeseed oil and rapeseed oil containing 1wt% Cu-DTP was evaluated using an Optimol SRV oscillating friction and wear tester. The wear mechanism was examined using scanning electron microscopy (SEM) and X-ray photoelectron spectrosmeter (XPS).

Fang Wang; Qin-Ling Bi; Xiao-Bo Wang; Wei-Min Liu

2008-01-01

314

Improvement in corrosion resistance of the 316l stainless steel by means of Al 2O 3 coatings deposited by the sol-gel method  

Microsoft Academic Search

Two-, four- and six-layer Al2O3 coatings of the AISI 316 type stainless steel have been prepared by means of the Sol-Gel method. As a precursor substance aluminium isopropoxide was used. The coatings were approx. 2–3 ?m thick and had amorphous structures. The higher sintering temperature (within the range 500–850°C), the lower cathode current density values, however also the lower breakdown

J. Masalski; J Gluszek; J Zabrzeski; K Nitsch; P Gluszek

1999-01-01

315

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

316

Characterization of AISI C115 steel shots produced by water-additive shotting at 1520 C  

SciTech Connect

Metallic powder production has been an important industrial activity for many years and several methods have been developed to produce metallic particles; including mechanical grinding, chemical reduction, chemical precipitation, electrolysis, and atomization. Physical fragmentation of a liquid metal by fluid impact is described as shotting if the resulting particles are bigger than 150 {micro}m and as atomization if the particles produced are smaller than 150 {micro}m. This paper presents a characterization of particles produced by water shotting. The effect of different operational parameters on characteristics and properties of particle production has been the focus of previous research, however, the effect of water additives on particle characteristics obtained by shotting has not been yet analyzed. During this study, a series of experimental tests were performed to determine if the use of additives in the water during the shotting process of an AISI C115 steel at 1520 C could modify the composition of particle coating, particle coating thickness, grain size in particles, particle microstructure, particle hardness, particle morphology, and particle size distribution.

Vargas, G.; Mendez, J.; Mendez, M.; Zaldivar, A.A.; Estrada, J.L.

1999-10-08

317

Investigation of mechanically attrited structures induced by repeated impacts on an AISI1045 steel  

NASA Astrophysics Data System (ADS)

Under repeated impact loadings - shot peening process, surface mechanical attrition treatment, erosive wear - metallic surfaces undergo severe plastic deformation which leads sometimes to a local change of their microstructure. These mechanically attrited structures (MAS) exhibit very interesting physical properties: high hardness, better tribological properties, etc. Consequently it is of primary importance to understand the mechanism explaining how these MAS are created and grow under such loadings. In this article, this mechanism is investigated with the help of a coupled experimental and finite element approach. First, the MAS are generated on an AISI1045 steel with a micro-impact tester which allows to know the impact energy and the location of impacts with a very good accuracy. The evolution of the MAS shape as a function of the impact number is presented. Then, the finite element investigation is presented. It is shown that a macroscopic stabilized elastic regime is reached after one hundred impacts. It also appears that a close cycle of plastic strain is observed locally in the zone where material transformation should happen during this regime. The severe plastic deformation achieved after a given number of cycles may thus explain the material transformation. Based on these results, we propose a mechanism based on a plastic strain threshold to explain the growth of the MAS. The resulting MAS size and shape appear to be in very good agreement with the experimental results. Finally, we conclude on the influence of the mechanical parameters that are involved in the proposed mechanism.

Kermouche, Guillaume; Pacquaut, Guillaume; Langlade, C.; Bergheau, Jean-Michel

2011-07-01

318

White Layer Formation Due to Phase Transformation to Orthogonal machine of AISI 1045 Annealed Steel  

SciTech Connect

It is commonly believed that the white layer formed during machining of steels is caused primarily by a thermally induced phase transformation resulting from rapid heating and quenching. As a result, it is often assumed that if the temperature at the tool flank-workpiece interface exceeds the nominal phase transformation temperature for the steel, a white layer forms. However, no attempt has been made to actually measure the temperatures produced at the tool flank-workpiece interface and correlate it with microstructural evidence of phase transformation. This paper aims to address these limitations through suitably designed experiments and analysis. Orthogonal machining tests were performed on AISI 1045 annealed steel at different cutting speeds and tool flank wear. During machining, temperature measurements at the tool flank-workpiece interface were made using an exposed thermocouple technique. Metallographic studies of the machined sub-surface and X-ray diffraction (XRD) measurements were performed to determine the presence and depth of white layer, and the presence of the retained austenite phase in the machined surface layer, respectively. Analysis of the data shows that the white layer can form due to phase transformation at temperatures below the nominal austenitization temperature of the steel. Possible causes of this result are presented.

Han, Sangil [ORNL; Melkote, Shreyes N [Georgia Institute of Technology; Haluska, Dr. Michael S [Georgia Institute of Technology; Watkins, Thomas R [ORNL

2008-01-01

319

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

320

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

321

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

322

Strengthening of an AISI 1020 steel by aluminum-microalloying during liquid dynamic compaction  

SciTech Connect

Grain size refinement was achieved in an AISI 1020 steel alloyed with 0.06 wt. % aluminum by liquid dynamic compaction (LDC), a rapid solidification spray deposition process. Atomization was done with nitrogen which resulted in incorporation of about 0.05 wt. % nitrogen in the spray deposited steel. The spray deposit showed a fine (10--40 {mu}m), equiaxed ferrite plus pearlite structure and a high as-deposited density of about 95% of theoretical. Minor reductions up to 70% in hot rolling plus annealing, both at low austenitic temperatures (850--900{degrees}C), fully densified the deposit and produced significantly finer (3--4 {mu}m) ferritic grains with uniformly distributed fine pearlite colonies. The grain size refinement resulted from pinning of prior austenitic grain boundaries by fine AIN particles which precipitated during the thermomechanical treatments (TMT). Room temperature yield and ultimate tensile strength values exceeding 80 and 90 ksi (550 and 620 MPa), respectively, were achieved at high ductility levels. The fine microstructures were stabilized by AIN precipitates even on reheating to temperatures up to 1100{degrees}C. 19 refs., 6 figs., 1 tab.

Matsuo, S.; Ando, T.; Zody, M.C.; Grant, N.J. (Massachusetts Inst. of Tech., Cambridge, MA (United States). Dept. of Materials Science and Engineering)

1991-01-01

323

Effect of Fine Particle Peening Treatment prior to Nitriding on Fatigue Properties of AISI 4135 Steel  

NASA Astrophysics Data System (ADS)

In this study, a new hybrid surface modification process, fine particle peening (FPP) treatment prior to nitriding, was proposed. In order to clarify the effects of FPP treatment prior to nitriding on the fatigue strength of notched AISI 4135 steel with a stress concentration factor Kt of 2.36, fatigue tests were conducted at room temperature using a rotational bending fatigue testing machine. Hardness and residual stress distributions were measured in order to characterize the surface-modified layer. As a result, the surface hardness of the FPP-treated specimen before nitriding was higher than that of the nitrided specimen. The surface microstructures of treated specimens were characterized using scanning electron microscopy (SEM) and X-ray diffraction (XRD). The crystal structure of the compound layer of the FPP-treated specimen before nitriding was different to that of the nitrided specimen. The compound layer of the FPP-treated specimen was dense. This suggests that FPP treatment prior to nitriding is very effective for improvement of the fatigue strength of steel.

Kikuchi, Shoichi; Komotori, Jun

324

Crack paths and hydrogen-assisted crack growth response in aisi 4340 steel. Technical report  

SciTech Connect

A study of the correlation and crack growth response was undertaken to better define the elemental processes involved in gaseous hydrogen embrittlement. AISI 4340 steel fracture under sustained load in hydrogen and in hydrogen sulfide over a range of temperatures and pressures, whose crack growth kinetics have been well characterized previously, was chosen for study. Fractographic results showed that crack growth followed predominantly along prior-austenite grain boundaries, with a small amount of quasi-cleavage, at low temperatures. At high temperatures, crack growth occurred primarily by microvoid coalescence. The fracture surface morphology, which is indicative of the micromechanisms for crack growth, was essentially the same for hydrogen and hydrogen sulfide. Changes in fracture morphology, i.e., crack paths, corresponded to changes in crack growth kinetics, both of which depended on pressure and temperature. There was no evidence for crack nucleation in advance of the main crack, and this suggests that the fracture process zone is located within one prior-austenite grain diameter from the crack tip.

Gao, M.; Lu, M.; Wei, R.P.

1983-09-01

325

On the fatigue crack growth resistance of upper bainite-martensite in an AISI 4330 steel  

SciTech Connect

Investigation on 4340 type low alloy high strength steels have shown that bainite-martensite mixed microstructures display, in certain cases, an improved combination of strength and toughness as compared to the behavior of these steels in the fully martensitic condition. The literature reveals that, in association with tempered martensite, lower bainite is the preferred form of bainite for improved mechanical behavior with about 25% by volume of lower bainite being an optimum proportion. On the other hand, the presence of upper bainite was seen to be detrimental. Contrary to these observations, the recent work on a vanadium containing steel corresponding to the AISI 4330 designation suggests that the presence of upper bainite in a mixed microstructure tempered at 473 K results in a significant improvement in toughness at the same strength level as that of the fully martensitic structure. Here the authors report in the same steel the fatigue crack growth behavior of upper bainite-martensite mixed structure. As was observed in regard to tensile properties and fracture toughness, the fatigue crack growth resistance of upper bainite-martensite mixed microstructure is shown to be superior by comparison with the behavior of the fully martensitic structure.

Saxena, V.K. (Defence Metallurgical Research Lab., Hyderabad (India)); Malakondaiah, G. (Wright-Patterson Air Force Base, OH (United States)); Radhakrishnan, V.M. (Indian Inst. of Tech., Madras (India)); Rao, P.R. (Jawaharlal Nehru Centre for Advance Research, Bangalore (India))

1993-05-15

326

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

327

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

328

Effect of Austenitizing Heat Treatment on the Microstructure and Hardness of Martensitic Stainless Steel AISI 420  

NASA Astrophysics Data System (ADS)

The effect of austenitizing on the microstructure and hardness of two martensitic stainless steels was examined with the aim of supplying heat-treatment guidelines to the user that will ensure a martensitic structure with minimal retained austenite, evenly dispersed carbides and a hardness of between 610 and 740 HV (Vickers hardness) after quenching and tempering. The steels examined during the course of this examination conform in composition to medium-carbon AISI 420 martensitic stainless steel, except for the addition of 0.13% vanadium and 0.62% molybdenum to one of the alloys. Steel samples were austenitized at temperatures between 1000 and 1200 °C, followed by oil quenching. The as-quenched microstructures were found to range from almost fully martensitic structures to martensite with up to 35% retained austenite after quenching, with varying amounts of carbides. Optical and scanning electron microscopy was used to characterize the microstructures, and X-ray diffraction was employed to identify the carbide present in the as-quenched structures and to quantify the retained austenite contents. Hardness tests were performed to determine the effect of heat treatment on mechanical properties. As-quenched hardness values ranged from 700 to 270 HV, depending on the amount of retained austenite. Thermodynamic predictions (using the CALPHAD™ model) were employed to explain these microstructures based on the solubility of the carbide particles at various austenitizing temperatures.

Barlow, L. D.; Du Toit, M.

2012-07-01

329

Effects of friction and high torque on fatigue crack propagation in mode III. [AISI 4140 and 4340  

SciTech Connect

Turbo-generator and automotive shafts are often subjected to complex histories of high torques. To provide a basis for fatigue life estimation in such components, a study of fatigue crack propagation in Mode III (anti-plane shear) for a mill-annealed AISI 4140 steel (R /SUB B/ 88, 590 MN/m/sup 2/ tensile strength) has been undertaken, using torsionally-loaded, circumferentially-notched cylindrical specimens. As demonstrated previously for higher strength AISI 4340 steel, Mode III cyclic crack growth rates (dc/dN) /SUB III/ can be related to the alternating stress intensity factor ..delta..K /SUB III/ for conditions of small-scale yielding. However, to describe crack propagation behavior over an extended range of crack growth rates (about 10/sup -6/ to 10/sup -2/ mm per cycle), where crack growth proceeds under elastic-plastic and full plastic conditions, no correlation between (dc/dN) /SUB III/ and ..delta..K /SUB III/ is possible. Accordingly, a new parameter for torsional crack growth, termed the plastic strain intensity GAMMA /SUB III/, is introduced and is shown to provide a unique description of Mode III crack growth behavior for a wide range of testing conditions, provided a mean load reduces friction, abrasion, and interlocking between mating fracture surfaces A micro-mechanical model for the main radial Mode III growth is extended to high nominal stress levels, and predicts that Mode III fatigue crack propagation rates should be proportional to the range of plastic strain intensity (..delta..GAMMA /SUB III/) if local Mode II growth rates are proportional to the displacements. Such predictions are shown to be in agreement with measured growth rates in AISI 4140 steel from 10/sup -6/ to 10/sup -2/ mm per cycle.

Nayeb-Hashemi, H.; McClintock, F.A.; Ritchie, R.O.

1982-12-01

330

Analyses of oxide films grown on AISI 304L stainless steel and Incoloy 800HT exposed to supercritical water environment  

NASA Astrophysics Data System (ADS)

Supercritical water (SCW) is being considered as a cooling medium for the next generation nuclear reactors because it provides high thermal efficiency and plant simplification. However, materials corrosion has been identified as a critical problem due to the oxidative nature of supercritical water. Thus, for safety using of these nuclear reactor systems a systematic study of candidate materials corrosion is needed. As in other high temperature environments, corrosion in SCW occurs by the growth of an oxide layer on the materials surface. The current work aims to evaluate oxidation behavior of AISI 304L SS and Incoloy 800HT in water at supercritical temperatures in the range 723-873 K under a pressure of 25 MPa for up to 1680 h. After exposure to deaerated supercritical water, the samples were investigated using gravimetry, scanning electron microscopy (SEM), energy dispersive X-ray spectroscopy (EDS), X-ray photoelectron spectroscopy (XPS), and electrochemical impedance spectroscopy (EIS). Oxide films grown on these materials have a layered structure with an outer layer consisting of a mixture of iron oxide/iron-nickel spinel oxides and an inner layer consisting of chromium oxide in the case of Incoloy 800HT and nickel-chromium spinel oxide in the case of AISI 304L SS. The mass gains for Incoloy 800HT at all temperatures were small, while comparatively with AISI 304L SS which exhibited higher oxidation rates. In the same time the results obtained by EIS indicate the best corrosion resistance of oxides grown on Incoloy 800HT surface.

Fulger, Manuela; Mihalache, Maria; Ohai, Dumitru; Fulger, Stefan; Valeca, Serban Constantin

2011-08-01

331

Cyclic oxidation of sputter-deposited nanocrystalline Fe-Cr-Ni-Al alloy coatings  

SciTech Connect

Nanocrystalline coatings of AISI 310S stainless steel with a small amount of Al were produced using unbalanced magnetron-sputter deposition with a composite target. Cyclic oxidation tests were performed at 800 and 900 C in air for 100 hr. The results showed that Al{sub 2}O{sub 3} scales formed on the coatings containing {approximately}3 wt.% Al. The oxidation rate of the coated specimens was much lower than that of the uncoated specimens and the scale spallation resistance was also improved significantly. Studies with atomic force microscopy (AFM) of the transient-oxidation surfaces suggested that grain-boundary and subgrain-boundary diffusion in the coatings may have played an important role in promoting the formation of the Al{sub 2}O{sub 3} scale. Fast creep of the fine-grain coating and alumina scale was considered to be the mechanism for the improvement in spallation resistance.

Liu, Z.; Gao, W.; Li, M. [Univ. of Auckland (New Zealand). Dept. of Chemical and Materials Engineering

1999-06-01

332

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

333

Influence of pulsating magnetic field on softening behavior of cold rolled AISI 4340 steel at room temperature  

SciTech Connect

The mechanical behavior of a ferromagnetic material is influenced by presence of magnetic field. The rate of stress relaxation in nickel increases by a.c. magnetic field of 11 Oersted (Oe) and 60 Hz. The application of 800 Oe steady magnetic field accelerates the process of creeping in high purity iron. The purpose of the present investigation was to examine the influence of pulsating magnetic field of 942 Oe, produced by a.c. current (50Hz), on the softening behavior of AISI 4340 steel, cold rolled to 20, 60, and 80%.

Prasad, S.N.; Singh, P.N.; Singh, V. [Banaras Hindu Univ., Varanasi (India)

1996-06-15

334

ALS Association  

MedlinePLUS

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335

Irradiation creep and swelling of AISI 316 to exposures of 130 dpa at 385 to 400/sup 0/C  

SciTech Connect

The creep and swelling of AISI 316 stainless steel have been studied at 385 to 400/sup 0/C in EBR-II to doses of 130 dpa. Most creep capsules were operated at constant stress and temperature but mid-life changes in these variable were also made. This paper concentrates on the behavior of the 20% cold-worked condition but five other conditions were also studied. Swelling at less than or equal to00/sup 0/C was found to lose the sensitivity to stress exhibited at higher temperatures while the creep rate was found to retain linear dependencies on both stress and swelling rate. The creep coefficients extracted at 400/sup 0/C agree with those found in other experiments conducted at higher temperatures. In the temperature range of less than or equal to400/sup 0/C, swelling is in the recombination-dominated regime and the swelling rate falls strongly away from the approx.1%/dpa rate observed at higher temperatures. These lower rates of creep and swelling, coupled with the attainment of high damage levels without failure, encourage the use of AISI 316 in the construction of water-cooled fusion first walls operating at temperatures below 400/sup 0/C. 23 refs., 8 figs.

Garner, F.A.; Porter, D.L.

1987-09-01

336

Effect of cold working and sandblasting on the microhardness, tensile strength and corrosion resistance of AISI 316L stainless steel  

NASA Astrophysics Data System (ADS)

The aim of this work is to investigate the effect of cold working and sandblasting on the microhardness, tensile strength and corrosion rate of AISI 316L stainless steel. The specimens were deformed from 17% to 47% and sandblasted for 20 min using SiC particles with a diameter of 500-700 ?m and an air flow with 0.6-0.7 MPa pressure. The microhardness distribution and tensile test were conducted and a measurement on the corrosion current density was done to determine the corrosion rate of the specimens. The result shows that the cold working enhances the bulk microhardness, tensile and yield strength of the specimen by the degree of deformation applied in the treatment. The sandblasting treatment increases the microhardness only at the surface of the specimen without or with a low degree of deformation. In addition, the sandblasting enhances the surface roughness. The corrosion resistance is improved by cold working, especially for the highly deformed specimen. However the follow-up sandblasting treatment reduces the corrosion resistance. In conclusion, the cold working is prominent to be used for improving the mechanical properties and corrosion resistance of AISI 316L stainless steel. Meanwhile, the sandblasting subjected to the cold worked steel is only useful for surface texturing instead of improving the mechanical properties and corrosion resistance.

Suyitno; Arifvianto, Budi; Widodo, Teguh Dwi; Mahardika, Muslim; Dewo, Punto; Salim, Urip Agus

2012-12-01

337

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

338

High temperature creep and cyclic deformation behaviour of AISI 316 L(N) austenitic steel and its modelling with unified constitutive equations  

Microsoft Academic Search

Creep tests at constant stress and low cycle fatigue (LCF) tests were performed with a view to investigating and modelling the deformation behaviour of AISI 316 L(N) austenitic stainless steel at 700 °C. All experiments were done on samples taken from two different sheets of the same batch of material.The creep stresses were selected from the high stress range. The

A. Haupt; D. Munz; W. Scheibe; B. Schinke; R. Schmitt; V. Sklenicka

1996-01-01

339

Application of Mössbauer spectroscopy to the study of corrosion resistance in NaCl solution of plasma nitrided AISI 316L stainless steel  

Microsoft Academic Search

Corrosion research in steels is one of the areas in which Mössbauer spectroscopy has become a required analytical technique, since it is a powerful tool for both identifying and quantifying distinctive phases (which contain Fe) with accuracy. In this manuscript, this technique was used to the study of corrosion resistance of plasma nitrided AISI 316L samples in the presence of

M. Olzon-Dionysio; S. D. de Souza; R. L. O. Basso

2008-01-01

340

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

341

Environmental cracking susceptibility of AISI 422 stainless steel in NH[sub 4]HCO[sub 3]/NH[sub 4]OH solution at 70 C  

SciTech Connect

The environmentally assisted cracking (EAC) susceptibility of AISI 422 (UNS S42200) stainless steel (SS) turbine blades was examined in an aerated NH[sub 4]HCO[sub 3]/NH[sub 4]OH solution at 70 C. Exposure in this solution is intended to simulate a cleaning procedure used to remove deposited copper from turbine blades in commercial power plants. EAC susceptibility is a strong function of the electrochemical potential; hence, it is necessary to compare the potential of contaminated blades to potential ranges such as the active-passive transition, which might promote EAC susceptibility. The ranking of open-circuit or mixed potentials experienced by the various materials/electrolyte combinations relative to the active-passive transition was polished SS/aerated > copper + SS/aerated > copper/aerated = SS active to passive transition > polished SS/deaerated. Constant extension rate tests were conducted by potentiostatically polarizing AISI 422 specimens to these potentials. For the displacement rate chosen, both tensile test parameters as well as scanning electron fractography revealed little differences between the environmental results and those obtained in air, except at the potential associated with the active-passive transition of the SS. However, this potential is 0.3 V more negative than the potential of the Cu-contaminated AISI 422 SS turbine blade. Hence, the chemical cleaning procedure does not promote EAC of AISI 422 SS unless the mixed potential experienced by the Cu-contaminated blades becomes more negative than expected.

Scully, J.R.; Scully, H.S. (Univ. of Virginia, Charlottesville (United States))

1993-02-01

342

Development of surface roughness prediction model using response surface methodology in high speed end milling of AISI H13 tool steel  

Microsoft Academic Search

This paper presents a study on the development of an effective method to predict surface roughness for high speed end milling of AISI H13 tool steel using PCBN inserts. The response surface methodology (RSM) has been utilized for the postulation of a second order quadratic model in terms of cutting speed, axial depth of cut and feed. Sufficient numbers of

A. M. K. Hafiz; A. K. M. N. Amin; A. N. M. Karim; M. A. Lajis

2007-01-01

343

Determination of damage functions for the pitting of AISI type 403 blade alloy and ASTM A470\\/471 disk alloy  

Microsoft Academic Search

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

Yancheng Zhang

2005-01-01

344

Evaluation of modulus of elasticity, nano-hardness and fracture toughness of TiB 2–TiC–Al 2O 3 composite coating developed by SHS and laser cladding  

Microsoft Academic Search

Modulus of elasticity (E) and nano-hardness (H) of the composite TiB2–TiC–Al2O3 coating deposited on AISI 1020 steel by combined self-propagating high-temperature synthesis (SHS) and laser cladding process have been measured from load–displacement curves, resulting from nano-indentation testing. Fracture toughness (KIC) of the coatings has been evaluated from the indentation method. A qualitative evaluation of interfacial strength between coating and substrate

Manoj Masanta; S. M. Shariff; A. Roy Choudhury

2011-01-01

345

Quantitative Evaluation of Aged AISI 316L Stainless Steel Sensitization to Intergranular Corrosion: Comparison Between Microstructural Electrochemical and Analytical Methods  

NASA Astrophysics Data System (ADS)

The evaluation of the degree of sensitization (DOS) to intergranular corrosion (IGC) of a commercial AISI 316L austenitic stainless steel aged at temperatures ranging from 550 °C to 800 °C during 100 to 80,000 hours was carried out using three different assessment methods. (1) The microstructural method coupled with the Strauss standard test (ASTM A262). This method establishes the kinetics of the precipitation phenomenon under different aging conditions, by transmission electronic microscope (TEM) examination of thin foils and electron diffraction. The subsequent chromium-depleted zones are characterized by X-ray microanalysis using scanning transmission electronic microscope (STEM). The superimposition of microstructural time-temperature-precipitation (TTP) and ASTM A262 time-temperature-sensitization (TTS) diagrams provides the relationship between aged microstructure and IGC. Moreover, by considering the chromium-depleted zone characteristics, sensitization and desensitization criteria could be established. (2) The electrochemical method involving the double loop-electrochemical potentiokinetic reactivation (DL-EPR) test. The operating conditions of this test were initially optimized using the experimental design method on the bases of the reliability, the selectivity, and the reproducibility of test responses for both annealed and sensitized steels. The TTS diagram of the AISI 316L stainless steel was established using this method. This diagram offers a quantitative assessment of the DOS and a possibility to appreciate the time-temperature equivalence of the IGC sensitization and desensitization. (3) The analytical method based on the chromium diffusion models. Using the IGC sensitization and desensitization criteria established by the microstructural method, numerical solving of the chromium diffusion equations leads to a calculated AISI 316L TTS diagram. Comparison of these three methods gives a clear advantage to the nondestructive DL-EPR test when it is used with its optimized operating conditions. This quantitative method is simple to perform; it is fast, reliable, economical, and presents the best ability to detect the lowest DOS to IGC. For these reasons, this method can be considered as a serious candidate for IGC checking of stainless steel components of industrial plants.

Sidhom, H.; Amadou, T.; Sahlaoui, H.; Braham, C.

2007-06-01

346

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

347

Influence of nickel ion implantation on the inactive braze joining abilities of Al 2O 3 ceramics  

Microsoft Academic Search

Multi-crystalline Al2O3 ceramics were implanted with 130keV Ni+ ion beams at 225°C in a vacuum of 1.33×10?3Pa. The inactive braze joining abilities of the implanted ceramic to 1Cr18Ni9Ti (AISI 321) stainless steel with Ag34Cu16Zn50 (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

B. R. Zhao; G. B. Li; P. Gao; T. Q. Lei; S. C. Song; X. J. Cao

2005-01-01

348

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

349

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

350

Corrosion-fatigue behavior of an annealed AISI 1045 carbon steel coated with electroless nickel-phosphorus  

SciTech Connect

The influence of an industrial electroless nickel-phosphorus deposit on the corrosion-fatigue properties of an annealed AISI 1045 steel has been investigated. For this purpose, three corrosive media were selected: distilled water and two NaCl solutions of different concentration (3 and 5%) in distilled water. Corrosion-fatigue tests were conducted at alternating stress levels ranging between 219 and 329 MPa at a frequency of 50 Hz. The corrosion-fatigue properties of the coated and uncoated substrates are very similar when testing is conducted in salty water. However, for testing in distilled water the corrosion-fatigue properties of coated substrates were diminished in relation to the uncoated material. The fractographic analysis of the fracture surfaces revealed the presence of fatigue marks within the electroless nickel-phosphorus deposit, which indicate that the fracture mechanism of the coating is associated to the cyclic loading of the material.

Pertuz, A.; Chitty, J.A.; Puchi, E.S. (Central Univ. of Venezuela, Caracas (Venezuela)); Hintermann, H. (Univ. of Neuchatel (Switzerland). Faculty of Sciences)

1999-08-01

351

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

352

Evaluation of Microstructure and Toughness of AISI D2 Steel by Bright Hardening in Comparison with Oil Quenching  

NASA Astrophysics Data System (ADS)

AISI D2 is used widely in the manufacture of blanking and cold-forming dies, on account of its excellent hardness and wear behavior. Increasing toughness at a fixed high level of hardness is growing requirement for this kind of tool steel. Improving microstructure characteristics, especially refinement of coarse carbides, is an appropriate way to meet such requirement. In this study, morphology and size of carbides in martensite matrix were compared between two kinds of samples, which were bright hardened (quenching in hot alkaline salt bath consisting of 60% KOH and 40% NaOH) at 230 °C and quenched in oil bath at 60 °C. Results showed that morphology and distribution of carbides in samples performed by bright hardening were finer and almost spherical compared to that of oil quenched. This microstructure resulted in an improvement in toughness and tensile properties of alloy.

Torkamani, H.; Raygan, Sh.; Rassizadehghani, J.

2011-12-01

353

Near surface chemistry and corrosion behavior of excimer laser surface-melted AISI type 304 stainless steel  

SciTech Connect

The effects of excimer laser surface melting on the near-surface chemistry, and corrosion behavior of AISI 304 stainless steel have been examined as a function of total energy deposited on the specimen. The surface chemistry resulting from the laser treatments has been examined using Auger electron spectroscopy. Electrochemical methods were used to monitor the corrosion behavior of the specimens in deaerated 0.1 M NaCl. Electron microscopy was used to characterize the extent of local corrosion of the specimens. Laser treatment was observed to increase the chromium concentration of the surface oxide and to reduce the number of pits. Two types of pits were observed on untreated material, but only one type of pit occurred after laser treatment. 7 refs., 5 figs.

Baer, D.R.; Frydrych, D.J.; Jervis, T.R.

1988-05-01

354

Experimental comparison of carbon-dioxide and liquid nitrogen cryogenic coolants in turning of AISI 1045 steel  

NASA Astrophysics Data System (ADS)

This experimental work is carried out to investigate the performance and influence of cryogenic coolants such as CO2 (carbon dioxide) and LN2 (liquid nitrogen) on cutting temperature, cutting force, tool wear, surface finish and chip morphology in machining of AISI 1045 steel compared to wet machining. The results proved that the application of cryogenic coolants reduced the cutting temperature drastically which resulted in appreciable improvement in surface finish of the product and reduced tool wear. The use of cryogenic LN2 reduced the cutting temperature about 3-17% when compared to CO2 coolant. Application of CO2 reduced the cutting forces and improved the surface finish of the machined part to an extent about 2-12% and 2-14% respectively when compared to the use of cryogenic LN2 coolant. Tool wear was found to be less on the application of CO2 compared to the wet and LN2 machining conditions.

Dilip Jerold, B.; Pradeep Kumar, M.

2012-10-01

355

The significance of passivation treatments on AISI 314 foam pieces to be used as substrates for catalytic applications  

NASA Astrophysics Data System (ADS)

Several properties of metallic foams such as their low density, high mechanical strength and good coefficients of heat and mass transfer make them attractive for applications in catalysis. Important modifications in the composition and morphology of the metallic foam surfaces can take place when they are submitted to treatments at high temperatures. These surface changes are due to the migration of some elements from the metallic core to the pore surface, thus inducing a passivation via an oxide layer formation. This new layer avoids further metallic segregation and generates a surface roughness, both effects having a significant impact on the catalytic coating quality. This work analyzes the effects of calcination temperature and time on the chemistry and morphology of the metallic surface corresponding to the AISI 314 stainless steel foams of 50 and 60 ppi. The chemical and morphological surface changes were characterized by X-Ray Diffraction (XRD), Scanning Electron Microscopy (SEM), Energy-Dispersive X-Ray (EDX) analysis and Laser Raman Spectroscopy (LRS). The application of high temperature treatments on AISI 314 foams promotes the formation of a surface layer containing chromium oxide and spinel-type compounds of chromium, iron and manganese. The optimum treatment temperature for this type of structures seems to be 900 °C because both the adhesion and thickness of the layer formed are adequate. For the sample with smaller pores (60 ppi) the optimal treatment time is close to 2 h and for that with larger pores (50 ppi) the recommended time is 20 h. Under these conditions, a compromise is found between adhesion, thickness and surface roughness, suitable for the subsequent deposition of catalytic material.

Bortolozzi, J. P.; Banús, E. D.; Milt, V. G.; Gutierrez, L. B.; Ulla, M. A.

2010-11-01

356

The effects of process variables on pulsed Nd:YAG laser spot welds; Part 1: AISI 409 stainless steel  

SciTech Connect

The weldabilities of AA 1,100 aluminum and AISI 409 stainless steel by the pulsed Nd:YAG laser welding process have been examined experimentally and compared. The effects of Nd:YAG laser welding parameters, including laser pulse time and power intensity, and material-dependent variables, such as absorptivity and thermophysical properties, on laser spot-weld characteristics, such as weld diameter, penetration, melt area, melting ratio, porosity, and surface cratering, have been studied experimentally. When welding AISI 409 stainless steel, weld pool shapes were found to be influenced most by the power intensity of the laser beam and to a lesser extent by the pulse duration. Conduction mode welding, keyhole mode welding, and drilling were observed. Conduction mode welds were produced when power intensities between 0.7 and 4 GW/m{sup 2} were used. The initial transient in weld pool development occurred in the first 4 ms of the laser pulse. The initial transient in weld pool development occurred in the first 4 ms of the laser pulse. Following this, steady-state conditions existed and conduction mode welds with aspect ratios (depth/width) of about 0.4 were produced. Keyhole mode welds were observed at power intensities greater than 4 GW/m{sup 2}. Penetration of these keyhole mode welds increased with increases in both power intensity and pulse time. The major weld defects observed in the stainless steel spot welds were cratering and large-occluded gas pores. Significant metal loss due to spatter was measured during the initial 2 ms of keyhole mode welds. With increasing power intensity, there was an increased propensity for occluded gas pores near the bottom of the keyhole mode welds.

Liu, J.T.; Weckman, D.C.; Kerr, H.W. [Univ. of Waterloo, Ontario (Canada). Dept. of Mechanical Engineering

1993-12-01

357

Efeito da hidrogenacao catodica a partir de solucoes contendo As(sub 2)O(sub 3) sobre aco inoxidavel tipo AISI 316. (Effect of the hydrogen charging of AISI 316 stainless steel from solutions containing As(sub 2) O(sub 3)).  

National Technical Information Service (NTIS)

The hydrogen charging of AISI 316 stainless steel has turned unstable the austenitic structure which partially decomposes into two phases: (epsilon) (hexagonal close packed) and (alpha) ' (body centered cubic). A 1 N H(sub 2) SO(sub 4) solution was used a...

S. D. Brito

1973-01-01

358

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

359

Investigations on the mechanical properties and microstructure of dissimilar cp-titanium and AISI 316L austenitic stainless steel continuous friction welds  

Microsoft Academic Search

Friction welding process is a solid state joining process that produces a weld under the compressive force contact of one rotating and one stationary work piece. In this study, the friction welding of dissimilar joints of AISI 316L stainless steel and cp-titanium is considered. The optical, scanning electron microscopy studies of the weld were carried out. Moreover, the X-ray diffraction

S. A. A. Akbarimousavi; M. GohariKia

2011-01-01

360

The occurrence of grain boundary serration and its effect on the M 23C 6 carbide characteristics in an AISI 316 stainless steel  

Microsoft Academic Search

M23C6 precipitation behaviors at the grain boundaries have been systematically investigated in an AISI 316 stainless steel. It is found that the grain boundary serration occurs at the early stage of aging treatment, before the M23C6 carbides precipitate. The occurrence of grain boundary serration is directly dependent on heat treatment condition, which is responsible for carbide characteristics. Planar carbides (low

H. U. Hong; S. W. Nam

2002-01-01

361

The passive behaviour of AISI 316 in alkaline media and the effect of pH: A combined electrochemical and analytical study  

Microsoft Academic Search

In this paper, thin surface films were formed on AISI 316 immersed in alkaline solutions of pH ranging from 13 to 9 under open circuit potential conditions. The electrochemical behaviour of the films formed under these conditions was evaluated by different electrochemical techniques: d.c. potentiodynamic polarisation, capacitance measurements (Mott–Schottky approach) and electrochemical impedance spectroscopy. The chemical composition was studied by

L. Freire; M. J. Carmezim; M. G. S. Ferreira; M. F. Montemor

2010-01-01

362

Effect of different environmental parameters on pitting behavior of AISI type 316L stainless steel: Experimental studies and neural network modeling  

Microsoft Academic Search

AISI type 316L stainless steel was subjected to electrochemical polarization tests in an aqueous environment of varying chloride ion concentration (17,500–70,000ppm), pH (1.23–5.0) and temperature (298–333K). Values of critical pitting potentials (Epit) were determined from the polarization tests. Increasing concentration and temperature, and decreasing pH were found to decrease the Epit. Eighty values of Epit, at different chloride concentrations, pH

K. V. S. Ramana; T. Anita; Sumantra Mandal; S. Kaliappan; H. Shaikh; P. V. Sivaprasad; R. K. Dayal; H. S. Khatak

2009-01-01

363

A comparative study of the wear behaviour of sintered and laser surface melted AISI M42 high speed steel diluted with iron  

Microsoft Academic Search

Powders of AISI M42 high-speed steel (HSS) were blended with different proportions of water-atomised iron powders. The powders were subsequently submitted to uniaxial pressing and then divided in three lots. The first was submitted to sintering, the second was submitted to sintering plus laser surface melting (LSM) and the third was submitted to sintering plus LSM plus double tempering at

R. Colaço; E. Gordo; E. M. Ruiz-Navas; M. Otasevic; R. Vilar

2006-01-01

364

Influence of cold-work level, solute, and helium content on the swelling of pure AISI 316 (Fe17Cr16. 7Ni2. 5Mo)  

Microsoft Academic Search

As part of a larger effort to study the influence and possible synergisms involving solutes, helium and cold working, a simple quaternary alloy representing AISI 316 without solutes was irradiated in the Oak Ridge Research Reactor (ORR). This alloy's composition is Fe-17Cr-16.7Ni-2.5Mo and is designated P-7 or pure 316. It was irradiated at 350, 550, and 650°C in each of

H. R. Brager; F. A. Garner

1982-01-01

365

Characterisation of Pristine and Recoated electron beam evaporation plasma-assisted physical vapour deposition Cr–N coatings on AISI M2 steel and WC–Co substrates  

Microsoft Academic Search

This paper is focussed on the characterisation of electron beam evaporation plasma-assisted physical vapour deposition Cr–N coatings deposited on AISI M2 steel and hardmetal (K10) substrates in two different conditions: Pristine (i.e., coated) and Recoated (i.e., stripped and recoated). Analytical methods, including X-ray diffraction (XRD), scanning electron microscopy, scratch adhesion and pin-on-disc tests were used to evaluate several coating properties.

J. C. Avelar-Batista; E. Spain; J. Housden; G. G. Fuentes; R. Rebole; R. Rodriguez; F. Montala; L. J. Carreras; T. J. Tate

2005-01-01

366

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  

Microsoft Academic Search

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,

Wisander

1978-01-01

367

The influence of reversion annealing behavior on the formation of nanograined structure in AISI 201L austenitic stainless steel through martensite treatment  

Microsoft Academic Search

Martensite treatment is one of the known thermo-mechanical processes that can be used for the grain refinement of metastable austenitic stainless steels. In this work, the martensite to austenite reversion behavior as well as its effect on the processing of nanocrystalline structure in an as-cast AISI 201L austenitic stainless steel was investigated. The as-cast specimens were first homogenized and then

A. Rezaee; A. Najafizadeh; A. Kermanpur; M. Moallemi

2011-01-01

368

Improving the erosion–corrosion resistance of AISI 316 austenitic stainless steel by low-temperature plasma surface alloying with N and C  

Microsoft Academic Search

The erosion–corrosion behaviour of low-temperature plasma surface alloyed AISI 316 austenitic stainless steel has been compared with untreated material using a newly developed slurry pot erosion–corrosion apparatus containing a slurry comprising 20wt.% silica sand and 3.5%NaCl at 40°C. The total erosion–corrosion wastage, the mechanical erosion under cathodic protection and the electrochemical corrosion were measured directly. Based on the data obtained

H. Dong; P.-Y. Qi; X. Y. Li; R. J. Llewellyn

2006-01-01

369

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

370

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

Microsoft Academic Search

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 premium grade H13 steel were heat treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples poured to different section thicknesses.

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

1995-01-01

371

A unified theory for some effects of hydrogen source, alloying¦elements, and potential on crack growth in martensitic AISI 4340 steel  

Microsoft Academic Search

The effects of hydrogen on crack growth in martensitic AISI 4340 steel are shown to be fundamentally the same whether the\\u000a hydrogen is supplied as molecular gas, through stress corrosion, or by electrolytic charging. At a given yield strength differences\\u000a observed in the values of threshold stress intensity for crack growth are proposed to be linked to the degree of

G. Sandoz

1972-01-01

372

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

373

Correlation of the Moessbauer effect and hydrogen embrittlement of AISI 4340 steel. Final technical report, 14 May 1970--14 May 1971  

Microsoft Academic Search

The relationship between Moessbauer Effect parameters and hydrogen embrittled steel was examined. The 14 keV gamma-rays were used for observation, penetrating a cadmium plating that slowed out-diffusion of the hydrogen. Standard 'around-the-corner' backscatter geometry was used. AISI 4340 steel, heat treated to strength levels of 260 - 280 ksi was used. Samples were in the form of C-rings with a

R. C. Folweiler; C. S. Naiman

1972-01-01

374

RESPUESTA DE PLANTAS DE MAÍZ Y FRIJOL AL ENRIQUECIMIENTO DE DIÓXIDO DE CARBONO MAIZE AND BEAN PLANTS RESPONSE TO CO2 ENRICHMENT  

Microsoft Academic Search

The effect of an atmosphere enriched with carbon dioxide (CO 2) was studied on some physiological and growth parameters of plants of Zea mays L. cv. H-30 and Phaseolus vulgaris L. cv. Cacahuate-72 grown in the field in open-top chambers. Two CO2 concentrations were established, normal (360 m m m m mmoles mol-1) and the enriched one (600- - -

Patricia Sánchez-Espino; Alfonso Larqué-Saavedra; Tomás Nava-Sánchez; Carlos Trejo

375

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

376

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

377

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

378

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

379

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.

2010-07-01

380

Corrosion behavior and tensile properties of AISI 316LN stainless steel exposed to flowing sodium at 823 K  

SciTech Connect

Austenitic stainless steel of the grade AISI 316 LN was exposed to flowing sodium in a loop at 823 K for 6,000 h to examine the corrosion and mass-transfer behavior. The specimens were incorporated in specially designed sample holders in the loop. These were retrieved and examined by various metallurgical techniques. Specimens were also subjected to thermal aging in the same sample holder to aid in separating the consequences of exposure to sodium from those cause by mere thermal effects. Microstructural investigations have revealed that thermal aging caused the precipitation of carbides at the grain boundaries. Exposure to sodium caused the leaching of elements such as chromium and nickel from the specimen. Loss of nickel from the austenite phase promoted the generation of ferrite phase. Microhardness investigation revealed the hardening of the sodium-exposed surface. Analysis using an electron Probe Microanalyzer revealed that the surface of the steel was both carburized and nitrided. Tensile tests indicated that there is no appreciable difference in the yield strength (YS) and ultimate tensile strength (UTS) of the thermally aged and sodium-exposed specimens when compared with the material in the as-received condition. However, the thermally aged and sodium-exposed specimens showed a decrease in the uniform elongation and total elongation at rupture, perhaps due to carburization and nitridation.

Pillai, S.R.; Barasi, N.S.; Khatak, H.S.; Terrance, A.L.E.; Kale, R.D.; Rajan, M.; Rajan, K.K.

2000-02-01

381

Effect of Nitrogen and Sensitization on the Microstructure and Pitting Corrosion Behavior of AISI Type 316LN Stainless Steels  

NASA Astrophysics Data System (ADS)

High-nitrogen stainless steels (SS) are receiving increased attention because of the advantages of their strength over the SS with nominal composition. However, they are susceptible to dichromium nitride (Cr2N) precipitation during thermal exposure between 873 and 1323 K resulting in sensitization and subsequent intergranular corrosion. Round tensile specimens of AISI type 316LN SS, with three different nitrogen content 0.07, 0.14, and 0.22 wt.% in mill-annealed and sensitized (973 K for 24 h) condition were studied for their pitting corrosion behavior. The results of the potentiodynamic anodic polarization studies were correlated with the results obtained using electrochemical impedance spectroscopy (EIS) technique. Critical pitting potential ( E pp) increased with increasing nitrogen content but the same was found to decrease on aging. The parameters indicating passive film stability measured by EIS revealed faster passive film dissolution as indicated by low polarization resistance, in sensitized condition and vice-versa in mill-annealed condition. The EIS results correlated well with the variation in the respective E pp obtained from the potentiodynamic polarization diagrams.

Poonguzhali, A.; Pujar, M. G.; Kamachi Mudali, U.

2013-04-01

382

Surface texturing of the carbon steel AISI 1045 using femtosecond laser in single pulse and scanning regime  

NASA Astrophysics Data System (ADS)

Surface texturing of the metals, including steels, gained a new dimension with the appearance of femtosecond lasers. These laser systems enable highly precise modifications, which are very important for numerous applications of metals. The effects of a Ti:sapphire femtosecond laser with the pulse duration of 160 fs, operating at 775 nm wavelength and in two operational regimes - single pulse (SP) and scanning regime, on a high quality AISI 1045 carbon steel were studied. The estimated surface damage threshold was 0.22 J/cm2 (SP). Surface modification was studied for the laser fluences of 0.66, 1.48 and 2.37 J/cm2. The fluence of 0.66 J/cm2, in both working regimes, induced texturing of the material, i.e. formation of periodic surface structures (PSS). Their periodicity was in accordance with the used laser wavelength. Finally, changes in the surface oxygen content caused by ultrashort laser pulses were recorded.

Staši?, J.; Gakovi?, B.; Perrie, W.; Watkins, K.; Petrovi?, S.; Trtica, M.

2011-10-01

383

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

384

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.

2011-12-01

385

Influence of electroless nickel-phosphorus deposits on the corrosion-fatigue life of notched and unnotched samples of an AISI 1045 steel  

SciTech Connect

Electroless nickel-phosphorus deposits of approximately 10% phosphorus and about 20 {micro}m thickness are shown either to have no effect or sometimes to increase the corrosion-fatigue properties of a quenched and tempered AISI 1045 steel in the stress amplitude range of 481 to 687 MPa, in the presence of an aqueous solution of 3% sodium chloride. Such an increase is produced when the stress amplitude is below 516 MPa. For the notched specimens, no substantial differences are found between the fatigue life of the coated and uncoated specimens.

Chitty, J.A.; Pertuz, A.; Puchi, E.S. [Central Univ. of Venezuela, Caracas (Venezuela); Hintermann, H. [Univ. of Neuchatel (Switzerland). Dept. of Mechanical Engineering

1999-02-01

386

Solid-state diffusion welding of wrought AISI 304 stainless steel to Nimonic AP-1 superalloy powder by hot isostatic pressing  

SciTech Connect

The diffusion welding characteristics of wrought AISI 304 stainless steel to a superalloy powder Nimonic AP-1 were examined in this study. After encapsulation, evacuation and degassing, the welds were hot isostatically pressed (HIPed) in two different cycles, i.e., 1,200 C (2,192 F)/3h/147 MPa and 1,270 C (2,318 F)/3h/121 MPa. A variation in surface condition of stainless steel was also studied for its influence on properties of the joints. These diffusion-welded joints were characterized for diffusion of alloying elements, microstructural features and tensile properties.

Somani, M.C.; Birla, N.C. [Defence Metallurgical Research Lab., Hyderabad (India); Tekin, A. [Istanbul Technical Univ., Istanbul (Turkey). Dept. of Chemical and Metallurgical Engineering

1998-02-01

387

Influence of electroless nickel-phosphorus deposits on the corrosion-fatigue life of notched and unnotched samples of an AISI 1045 steel  

NASA Astrophysics Data System (ADS)

Electroless nickel-phosphorus deposits of approximately 10% phosphorus and about 20 µm thickness are shown either to have no effect or sometimes to increase the corrosion-fatigue properties of a quenched and tempered AISI 1045 steel in the stress amplitude range of 481 to 687 MPa, in the presence of an aqueous solution of 3% sodium chloride. Such an increase is produced when the stress amplitude is below 516 MPa. For the notched specimens, no substantial differences are found between the fatigue life of the coated and uncoated specimens.

Chitty, J. A.; Pertuz, A.; Hintermann, H.; Puchi, E. S.

1999-02-01

388

Metal objects mapping after small charge explosions. A study on AISI 304Cu steel with two different grain sizes.  

PubMed

Evidence of exposure of a metal component to a small charge explosion can be detected by observing microstructural modifications; they may be present even if the piece does not show noticeable overall plastic deformations. Particularly, if an austenitic stainless steel (or another metal having a face-centered cubic structure and a low stacking fault energy) is exposed to an explosive shock wave, high-speed deformation induces primarily mechanical twinning, whereas, in nonexplosive events, a lower velocity plastic deformation first induces slip. The occurrence of mechanical twins can be detected even if the surface is damaged or oxidized in successive events. In the present research, optical metallography (OM) and scanning electron microscopy (SEM), and scanning tunneling microscopy (STM) were used to detect microstructural modifications caused on AISI 304Cu steel disks by small-charge explosions. Spherical charges of 54.5 or 109 g TNT equivalent mass were used at explosive-to-target distances from 6.5 to 81.5 cm, achieving peak pressures from 160 to 0.5 MPa. Explosions induced limited or no macro-deformation. Two alloy grain sizes were tested. Surface OM and SEM evidenced partial surface melting, zones with recrystallization phenomena, and intense mechanical twinning, which was also detected by STM and X-ray diffraction. In the samples' interior, only twins were seen, up to some distance from the explosion impinged surface and again, at the shortest charge-to-sample distances, in a thin layer around the reflecting surface. For forensic science locating purposes after explosions, the maximum charge-to-target distance at which the phenomena disappear was singled out for each charge or grain size and related to the critical resolved shear stress for twinning. PMID:16696699

Firrao, Donato; Matteis, Paolo; Scavino, Giorgio; Ubertalli, Graziano; Ienco, Maria G; Pellati, Gabriella; Piccardo, Paolo; Pinasco, Maria R; Stagno, Enrica; Costanza, Girolamo; Montanari, Roberto; Tata, Maria E; Brandimarte, Giovanni; Petralia, Santo

2006-05-01

389

AISI/DOE Technology Roadmap Program: A Technology of Low Coal Rate and High Productivity of RHF Ironmaking  

SciTech Connect

An economical and environment-friendly ironmaking process based on heating the chemiexecy self-sufficient green balls of iron ore and coal in a hearth furnace is being developed with financial support from AISI members and DOE. DRI, which is hot (1400 C), dense (3.2 g/cm) and of high degree of metallization (95%), has been produced in laboratory and in a pilot plant in Genoa, Italy. Products of such quality have been made from American and Brazilian ores, BOF sludge, EAF dust/BOF sludge mixtures and millscale. The removal of zinc and lead from green balls by this process is essentially complete. In comparison with typical blast furnace operation, the new technology with a melter would have a lower total coal rate by 200kg.THM. The elimination of cokemaking and high temperature agglomeration steps, and a simpler gas handling system would lead to lower capital and operating costs. In comparison with commercial RHF practice it is different in atmosphere (fully oxidized at 1600 to 1650 C), in bed height (120 mm instead of 20-25 mm) and in pellet composition (much less coal but of higher VM). The combined effect leads to three times higher furnace productivity, lower coal consumption and superior DRI quality. The risk of re-oxidation (slag formation) and dusty operation are practiexecy eliminated. The process is stable, tolerant and independent of the size, shape and movement of the hearth. However, materials handling (e.g., discharge of hot DRI) and the exact energy savings have to be established in a larger furnace, straight or rotary, and in a continuous mode of operation.

Wei-Kao Lu

2002-09-15

390

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

SciTech Connect

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 premium grade H13 steel were heat treated and characterized similarly for comparison. Microstructural differences were observed in as-cast samples poured to different section thicknesses. Dendrite cell size and carbide morphology constituted the most prominent microstructural differences observed. After a full heat treatment, however, Microstructural differences between the wrought material and cast materials were slight regardless of section thickness. The mechanical properties of the cast and heat treated material proved similar to the properties of the standard heat treated wrought material. A thermal fatigue testing unit was designed and built to correlate the heat checking susceptibility of AISI H13 steel to its processing and consequent microstructural condition. Surface hardness decreased significantly with thermal cycling, and heat checking was noticed in as few as 50 cycles. Thermal softening and thermal fatigue susceptibility were quantified and discussed relative to the microstructural conditions created by processing and heat treatment. It was found that the premium grade wrought H13 steel provided the best overall resistance to heat checking; however, the heat-treat cast and as-cast H13 tool steel (made from standard grade wrought H13 tool steel) provided comparable resistance to heat checking in terms Of area fraction of heat checking and maximum crack length.

Hochanadel, P.W.; Edwards, G.R. [Colorado School of Mines, Golden, CO (United States); Maguire, M.C.; Baldwin, M.D. [Sandia National Labs., Albuquerque, NM (United States)

1995-07-01

391

Evolution of Relationships Between Dislocation Microstructures and Internal Stresses of AISI 316L During Cyclic Loading at 293 K and 573 K (20 °C and 300 °C)  

NASA Astrophysics Data System (ADS)

The evolution of dislocation densities and of dislocation microstructures during cyclic loading of AISI 316L is systematically evaluated. In addition, internal stresses are also measured for every cycle and comprehensively analyzed. These observations are made in order to establish relationships between the evolution of dislocation condition and internal stresses, and ultimately to obtain a thorough insight into the complex cyclic response of AISI 316L. Moreover, the dependencies of established relationships on the variation of temperature and strain amplitude are investigated. The back stresses (long-range stresses associated with the presence of collective dislocations over different length scales) are mainly responsible for the cyclic deformation response at high strain amplitudes where dislocations tend to move more quickly in a wavy manner. In contrast, the effective stress, coupling with short-range dislocation interactions, plays an insignificant role on the material cyclic response for wavy slip conditions, but increasingly becomes more important for planar slip conditions. The additionally strong short-range interactions between dislocations and point defects (initially with solute atoms and later in life with corduroy structure) at 573 K (300 °C) cause dislocations to move in more planar ways, resulting in a significant increase in effective stress, leading to their influential role on the material cyclic response.

Pham, Minh-Son; Holdsworth, Stuart R.

2013-09-01

392

Low Temperature Sensitization on the Orthogonal Surfaces of Prior Deformed AISI 304LN and Aged at 673 K to 873 K (400 °C to 600 °C)  

NASA Astrophysics Data System (ADS)

This study investigates the sensitization behavior of AISI 304LN deformed previously by cold rolling (CR) to 5 pct to 25 pct reduction in thickness and aged at 673 K to 873 K (400 °C to 600 °C). The emphasis was on revealing the degree of sensitization (DOS) resulting from low-temperature sensitization (LTS) on the orthogonal surfaces and correlation thereof with the changes in various metallurgical properties caused by cold rolling. It was found that the DOS differs among the orthogonal surfaces such as the rolling surface (RS), transverse surface (TS), and cross transverse surface (CTS). RS showed lower DOS compared with CTS and TS. The differences in the DOS were attributed to the combined effect of deformation-induced martensite (DIM), grain size, and slip band formation. A deformation of 5 pct was critical to the susceptibility of AISI 304LN to intergranular (IGC) and transgranular corrosion (TGC). The sensitization kinetics was slow or saturated leading to desensitization beyond 5pct deformations at 773 K (500 °C) and 873 K (600 °C). It was, however, uniformly accelerated over 5 to 25 pct deformation when aged at 673 K (400 °C).

Singh, Raghuvir; Chowdhury, S. Ghosh; Das, Gautam; Singh, P. K.; Chattoraj, I.

2012-03-01

393

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

394

Brazed joints of CBN grains and AISI 1045 steel with AgCuTi-TiC mixed powder as filler materials  

NASA Astrophysics Data System (ADS)

The brazing process of cubic boron nitride (CBN) grains and AISI 1045 steel with AgCuTi-TiC mixed powder as a filler material was carried out. The joining strength and the interfacial microstructure were investigated. The experimental results indicate that the spreading of the molten filler material on AISI 1045 steel is decreased with the increase of TiC content. A good interface is formed between the TiC particulates and AgCuTi alloy through the wetting behavior. In the case of AgCuTi+16wt% TiC, the strength of the brazed steel-to-steel joints reached the highest value of 95 MPa dependent upon the reinforcement effect of TiC particles within the filler layer. Brazing resultants of TiB2, TiB, and TiN are produced at the interface of the CBN grains and the AgCuTi-TiC filler layer by virtue of the interdiffusion of B, N, and Ti atoms.

Ding, Wen-Feng; Xu, Jiu-Hua; Chen, Zhen-Zhen; Su, Hong-Hua; Fu, Yu-Can

2011-12-01

395

Amyotrophic Lateral Sclerosis (ALS)  

MedlinePLUS

... progressive, invariably fatal neurological disease that attacks the nerve cells (neurons) responsible for controlling voluntary muscles. In ALS, ... Information New gene mutations linked to ALS and nerve cell growth dysfunction Researchers have linked newly discovered gene ...

396

Response to annealing and reirradiation of AISI 304L stainless steel following initial high-dose neutron irradiation in EBR-II. [LMFBR  

SciTech Connect

The object of this study was to measure the stability of irradiation-induced microstructure upon annealing and, by selectively annealing out some of these features and reirradiating the material, it was expected that information could be gained concerning the role of microstructural changes in the void swelling process. Transmission electron microscopic examinations of isochronally annealed (200 to 1050/sup 0/C) AISI 304L stainless steel, which had been irradiated at approximately 415/sup 0/C to a fast (E > 0.1 MeV) neutron fluence of approximately 5.1 x 10/sup 26/n/m/sup 2/, verified that the two-stage hardness recovery with temperatures was related to a low temperature annealing of dislocation structures and a higher temperature annealing of voids and solute redistribution.

Porter, D.L.; McVay, G.L.; Walters, L.C.

1980-01-01

397

Influence of thermomechanical treatment and environmental history on creep, swelling and embrittlement of AISI 316 at 400/degree/C and 130 DPA  

SciTech Connect

A comprehensive creep experiment on AISI 316 stainless steel involving irradiation at /approximately/400/degree/C to 130 dpa has been completed. The influence of material and environmental variables on creep and swelling of this steel at /approximately/400/degree/C is shown to have many similarities with the behavior exhibited in an earlier experiment conducted at /approximately/550/degree/C, but significant differences are also apparent. These arise because the 400/degree/C experiment was clearly conducted in a regime dominated by the kinetics of point defect recombination whereas the 550/degree/C experiment was conducted in the sink-dominated regime. At 400/degree/C it is also found that a severe embrittlement arises concurrent with /approximately/10% swelling, requiring careful handling of test specimens and structural assemblies at room temperature. 19 refs., 19 figs.

Porter, D.L.; Wood, E.L.; Garner, F.A.

1988-09-01

398

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

399

An experimental analysis of process parameters to manufacture micro-channels in AISI H13 tempered steel by laser micro-milling  

NASA Astrophysics Data System (ADS)

This paper reports the characterization of laser machining (milling) process to manufacture micro-channels in order to understand the incidence of process parameters on the final features. Selection of process operational parameters is highly critical for successful laser micromachining. A set of designed experiments is carried out in a pulsed Nd:YAG laser system using AISI H13 hardened tool steel as work material. Several micro-channels have been manufactured as micro-mold cavities varying parameters such as scanning speed (SS), pulse intensity (PI) and pulse frequency (PF). Results are obtained by evaluating the dimensions and the surface finish of the micro-channel. The dimensions and shape of the micro-channels produced with laser-micro-milling process exhibit variations. In general the use of low scanning speeds increases the quality of the feature in both surface finishing and dimensional.

Teixidor, D.; Ferrer, I.; Ciurana, J.

2012-04-01

400

Effect of Proximity and Dimension of Two Artificial Pitting Holes on the Fatigue Endurance of Aluminum Alloy AISI 6061-T6 Under Rotating Bending Fatigue Tests  

NASA Astrophysics Data System (ADS)

This work deals with the study of the two artificial pitting holes effects, caused by their dimensions and proximity, on the fatigue endurance of aluminum alloy AISI 6061-T6 under rotating bending fatigue tests. Stress concentration induced by artificial pitting holes is analyzed and correlated with the experimental fatigue life. It is found that the stress concentration increases exponentially when the two pitting holes approach, and this induces an important reduction in the fatigue life. Concerning the diameter variation of one pitting in regard to the second, no important influence was observed on fatigue life for a given separation between them; this implies that the separation between the two artificial pitting holes and the associated stress concentration is the principal parameter on the fatigue life under these conditions. Finally, results are discussed and conclusions are presented involving the fatigue life, proximity, and dimension of pitting holes, stress concentration factor, and fracture surfaces where the failure origin is identified.

Dominguez Almaraz, G. M.; Mercado Lemus, V. H.; Villalon Lopez, J. J.

2012-08-01

401

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

402

Microstructures and Mechanical Performance of Plasma-Nitrided Al0.3CrFe1.5MnNi0.5 High-Entropy Alloys  

NASA Astrophysics Data System (ADS)

This study investigates the effect of plasma nitriding at 798 K (525 °C) on microstructures and the mechanical performance of Al0.3CrFe1.5MnNi0.5 high-entropy alloys (HEAs) obtained using different cast and wrought processing. All the alloys can be well nitride, with a thickness of around 80 ?m, and attain a peak hardness level around Hv 1300 near the surface. The main nitride phases are CrN, AlN, and (Mn, Fe)4N. Those of the substrates are bcc, fcc, Al-, and Ni-rich B2 precipitates, and ? phase. Their relative amounts depend on the prior processing and also change under the heat treatment during nitriding. The formation of ? phase during nitriding could in-situ harden the substrate to attain the suitable level required for wear applications. This gives the advantage in simplifying the processing for making a wear-resistance component or a mold since austenitizing, quench hardening, and tempering required for steels such as SACM and SKD steels are no longer required and final finishing can be accomplished before nitriding. Nitrided Al0.3CrFe1.5MnNi0.5 samples have much better wear resistance than un-nitrided ones by 49 to 80 times and also exhibit superior adhesive wear resistance to conventional nitrided alloys: nitriding steel SACM-645 (AISI 7140), 316 stainless steel, and hot-mold steel SKD-61 (AISI H13) by 22 to 55 times depending on prior processing. The superiority is due to the fact that the present nitrided alloys possess a much thicker highly hardened layer than the conventional alloys.

Tang, Wei-Yeh; Chuang, Ming-Hao; Lin, Su-Jien; Yeh, Jien-Wei

2012-07-01

403

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

404

Evolution of Al Qaeda.  

National Technical Information Service (NTIS)

Al Qaeda is a significant threat to the national security of the United States and its allies. This makes it important for individuals in these countries, both military and civilian, to understand the evolution of this threat. This thesis analyzes Al Qaed...

S. P. Wilson

2007-01-01

405

Cyclic response-electrochemical interaction in mono- and polycrystalline AISI 316L stainless steel in H[sub 2]SO[sub 4] solution-III. Potential dependence of the mechanical behavior during corrosion fatigue  

Microsoft Academic Search

Measurements of mechanical parameters and surface examinations have been carried out on mono- and polycrystalline specimens of an AISI 316L stainless steel which were cycled in a 1N H[sub 2]SO[sub 4] solution. Analysis was made in relation to both the number of cycles and the applied potentials. The environment was found to have no influence on such bulk properties as

Y. F. Li; G. C. Farrington; C. Laird

1993-01-01

406

THE INFLUENCE OF COLDWORK LEVEL ON THE IRRADIATION CREEP AND The Influence of ColdWork Level on The Irradiation Creep and Swelling of AISI 316 Stainless Steel Irradiated as Pressurized Tubes In The EBR-II Fast Reactor  

Microsoft Academic Search

Pressurized tubes of AISI 316 stainless steel irradiated in the P-1 experiment in the EBR-II fast reactor have been measured to determine the dependence of irradiation-induced strains resulting from plastic deformation, irradiation creep, void swelling and precipitation. It is shown that the Soderberg relation predicting no axial creep strains in biaxially-loaded tubes is correct for both plastic and creep strains.

Edgar R. Gilbert; Francis A. Garner

2006-01-01

407

The influence of cold-work level on the irradiation creep and swelling of AISI 316 stainless steel irradiated as pressurized tubes in the EBR-II fast reactor  

Microsoft Academic Search

Pressurized tubes of AISI 316 stainless steel irradiated in the P-1 experiment in the EBR-II fast reactor have been measured to determine the dependence of irradiation-induced strains resulting from plastic deformation, irradiation creep, void swelling and precipitation. It is shown that the Soderberg relation predicting no axial creep strains in biaxially-loaded tubes is correct for both plastic and creep strains.

E. R. Gilbert; F. A. Garner

2007-01-01

408

Modeling of the temperature field in the chip and in the tool in high-speed machining of a carbon steel: effect of pearlite to austenite phase transition in AISI 1075  

Microsoft Academic Search

A one-dimensional transient finite-difference model for the temperature distribution in orthogonal metal cutting, which was\\u000a originally developed by Boothroyd, and then improved upon by Tlusty, is used to calculate the temperature field in the chip\\u000a and in the tool in orthogonal cutting of AISI 1075 steel. In a series of compression tests using the NIST pulse-heated Kolsky\\u000a bar, a phase

T. J. Burns; S. P. Mates; R. L. Rhorer; E. P. Whitenton; D. Basak; R. H. McFadden

2010-01-01

409

Corrosion and corrosive wear of annealed, impact-fractured and slow bending-fractured surface layers of AISI 1045 steel in a 3.5% NaCl solution  

Microsoft Academic Search

Previous studies have demonstrated that the wear-corrosion synergism can be markedly affected by the loading speed. In this study, effects of the loading speed or strain rate on corrosion and corrosive wear of annealed, impact-fractured and slow bending-fractured surface layers of AISI 1045 steel in a 3.5% NaCl solution were investigated using electrochemical, scanning Kelvin probing and electrochemical scratching techniques.

S. B. Yin; D. Y. Li

2005-01-01

410

What Is ALS?  

MedlinePLUS

... to be involuntary. Remember, though, while you cannot stop your heart, you can hold your breath - so be aware ... trials that hold promise. Importantly, there are significant devices ... ALS ‘burns out,’ stops progressing or progresses at a very slow rate. ...

411

MDA ALS Caregiver's Guide  

MedlinePLUS

... day along the way. Lynne Nieto Corona del Mar, Calif. MDA ALS Division Co-Chair Publications Magazines ... 8 — Finding Caregiving Help Chapter 9 — End-of Life Issues Appendices MDA in Your Community Stay informed. ...

412

Iraq and Al Qaeda.  

National Technical Information Service (NTIS)

In building a case for invading Iraq and ousting Saddam Hussein from power, the Administration asserted that the regime of Saddam Hussein had a working relationship with the Al Qaeda organization. The Administration stated that the relationship dated to t...

K. Katzman

2007-01-01

413

Al-Qaeda  

Microsoft Academic Search

al-Qaeda, referred to as ‘the Base’ was founded in 1989 by Osama bin Laden and other like-thinking militant Muslims as the ultimate outcome of the 1979 invasion\\u000a of Afghanistan by the USSR. Initially, al-Qaeda was created to record and track down the names of the mujahideen listed as missing during the guerrilla war against the USSR.

Anne Rathbone; Charles K. Rowley

414

High temperature oxidation of mechanically alloyed NiAl–Fe–AlN–Al 2O 3  

Microsoft Academic Search

A new NiAl–Fe alloy containing uniformly distributed ultra-fine AlN and Al2O3 dispersoids was produced by mechanical alloying in a controlled atmosphere and by subsequent hot extrusion process. The new NiAl–Fe–AlN–Al2O3 alloy was oxidized in the temperature range between 1073 and 1473 K in air. The alloy displayed similar oxidation behavior with conventional NiAl alloys. As the oxidation temperature increased, the

D. B. Lee; G. Y. Kim; S. W. Park; S. C. Ur

2002-01-01

415

Characteristics of diamond-like carbon film synthesized on AISI 304 austenite stainless steel using plasma immersion ion implantation and deposition  

NASA Astrophysics Data System (ADS)

This study examines the characteristics of diamond-like carbon (DLC) film synthesized on AISI 304 austenite stainless steel by means of a hybrid process of plasma immersion ion implantation and deposition (PIII&D) maintained at 60 °C. The former and latter processes under investigation were carried out using methane (0 20 kV) and acetylene (1 2 kV, 0.13 0.40 Pa) plasmas, respectively. Glow discharge spectrometry (GDS), Raman scattering spectroscopy (RSS), atomic force microscopy (AFM), a nano-indentation probe (NIP) and a Rockwell-C hardness tester were employed to characterize, respectively, elemental depth profiles, sp3-to-sp2 ratio, surface morphology, hardness and adhesion strength of the DLC specimen. The results revealed that the mixing layer at the interface generated by plasma immersion ion implantation of methane at a higher voltage could enhance adhesive strength of the DLC film to the substrate. Furthermore, a higher sp3-to-sp2 ratio, a smoother surface, greater hardness, but weaker adhesion strength were obtained for the DLC film synthesized using plasma immersion ion deposition of acetylene at a lower bias voltage or higher gas pressure.

Liang, J. H.; Chen, M. H.; Tsai, W. F.; Lee, S. C.; Ai, C. F.

2007-04-01

416

Mitigation of stress corrosion cracking of AISI 304 stainless steel in oxygenated water at 289 degree C by organic species at low concentration  

SciTech Connect

In constant-extension-rate tests on sensitized AISI 304 stainless steel (SS) at 289{degree}C, some organic substances (oxygen scavengers) in feedwater containing {approximately}0.2 ppm dissolved oxygen decrease effluent oxygen concentration, electrochemical potential (ECP) of the steel, and stress corrosion cracking (SCC) susceptibility to very low levels. Other organic substances neither decrease oxygen concentration nor ECP of the steel significantly, but also mitigate SCC susceptibility relative to that in high-purity oxygenated water. The latter species apparently block active sites where cathodic reduction of oxygen occurs and thereby limit anodic dissolution of metal at the crack tip in a slip-dissolution mechanism of crack advance. In SCC tests on fracture-mechanics-type specimens under high-load-ratio, low-frequency cyclic loading conditions at 289{degree}C, the organic inhibitors at a concentration of {approximately}1.0 ppm stop crack growth in the sensitized steel, but are not effective in oxygenated water containing ionic impurities such as sulfate or chloride at the 0.1-ppm level. These results are consistent with the site blockage mechanism for different species that undergo cathodic reduction and control the rate of crack growth of the steel in the SCC tests. 39 refs., 5 figs., 4 tabs.

Kassner, T.F.; Ruther, W.E.; Soppet, W.K.

1989-10-01

417

Influence of cold-work level, solute, and helium content on the swelling of pure AISI 316 (Fe-17Cr-16. 7Ni-2. 5Mo)  

SciTech Connect

As part of a larger effort to study the influence and possible synergisms involving solutes, helium and cold working, a simple quaternary alloy representing AISI 316 without solutes was irradiated in the Oak Ridge Research Reactor (ORR). This alloy's composition is Fe-17Cr-16.7Ni-2.5Mo and is designated P-7 or pure 316. It was irradiated at 350, 550, and 650/sup 0/C in each of the following conditions: annealed, 20 percent cold worked, annealed plus helium implanted, 20 percent cold worked plus helium implanted and various annealed or cold work plus implanted and aged conditions. The implanted specimens contained a range of helium concentrations injected at ambient temperatures. All specimens chosen for examination by electron microscopy and immersion density were irradiated at 3 to 5 dpa. In agreement with an earlier microchemically-based prediction it was found that both the volume and density of voids were insensitive to cold work in an alloy lacking minor solutes such as silicon and carbon.

Brager, H.R.; Garner, F.A.

1982-04-01

418

Thermally Nitrided Stainless Steels for Polymer Electrolyte Membrane Fuel Cell Bipolar Plates: Part 2: Beneficial Modification of Passive Layer on AISI446  

SciTech Connect

Thermal nitridation of AISI446 mod-1 superferritic stainless steel for 24 h at 1100 C resulted in an adherent, inward growing surface layer based on (Cr, Fe){sub 2}N{sub 1-x} (x = 0--0.5). The layer was not continuous, and although it resulted in low interfacial contact resistance (ICR) and good corrosion resistance under simulated polymer electrolyte membrane fuel cell (PEMFC) cathodic conditions; poor corrosion resistance was observed under simulated anodic conditions. Nitridation for 2 h at 1100 C resulted in little nitrogen uptake and a tinted surface. Analysis by SEM, XPS, and AES suggested a complex heterogeneous modification of the native passive oxide film by nitrogen rather than the desired microns-thick exclusive Cr-rich nitride layer. Surprisingly, this modification resulted in both good corrosion resistance under simulated cathodic and anodic conditions and low ICR, well over an order of magnitude lower than the untreated alloy. Further, little increase in ICR was observed under passivating polarization conditions. The potential of this phenomenon for PEMFC bipolar plates is discussed.

Wang, Heli [National Renewable Energy Laboratory (NREL); Brady, Michael P [ORNL; More, Karren Leslie [ORNL; Meyer III, Harry M [ORNL; Turner, John [National Renewable Energy Laboratory (NREL)

2004-01-01

419

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

420

Microstructural characterization and tribocorrosion behaviour of Al\\/Al 3Ti and Al\\/Al 3Zr FGMs  

Microsoft Academic Search

Al\\/Al3Ti and Al\\/Al3Zr functionally graded materials (FGMs) were manufactured through a centrifugal method from Al–5 mass % Ti and Al–5 mass % Zr, respectively. Applied centrifugal forces were 30, 60 and 120 G (units of gravity). Microstructural characterization was performed and the influence of the reinforcing phase on the tribocorrosion behaviour of the FGMs was investigated. An increase in both

S. C. Ferreira; P. D. Sequeira; Yoshimi Watanabe; E. Ariza; L. A. Rocha

2011-01-01

421

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

422

ALS superbend magnet system  

SciTech Connect

The Lawrence Berkeley National Laboratory is preparing to upgrade the Advanced Light Source (ALS) with three superconducting dipoles (Superbends). In this paper we present the final magnet system design which incorporates R&D test results and addresses the ALS operational concerns of alignment, availability, and economy. The design incorporates conduction-cooled Nb-Ti windings and HTS current leads, epoxy-glass suspension straps, and a Gifford-McMahon cryocooler to supply steady state refrigeration. We also present the current status of fabrication and testing.

Zbasnik, J.; Wang, S.T.; Chen, J.Y.; DeVries, G.J.; DeMarco, R.; Fahmie, M.; Geyer, A.; Green, M.A.; Harkins, J.; Henderson, T.; Hinkson, J.; Hoyer, E.H.; Krupnick, J.; Marks, S.; Ottens, F.; Paterson, J.A.; Pipersky, P.; Portmann, G.; Robin, D.A.; Schlueter, R.D.; Steier, C.; Taylor, C.E.; Wahrer, R.

2000-09-15

423

Creep Behavior of Al-Rich Fe-Al Intermetallics.  

National Technical Information Service (NTIS)

The compression creep behavior of two dual-phase intermetallic alloys (FeAl2-Fe2Al5 and FeAl3-Fe2Al5) was investigated over the temperature range 600-1000 deg C. A normal primary creep stage, stress exponent between 4 and 5, and normal creep transient aft...

Y. L. Jeng E. J. Lavernia R. M. Hayes J. Wolfenstine

1995-01-01

424

Al/Al-oxide nanophase composites: Hardness and NMR Results  

NASA Astrophysics Data System (ADS)

Hardness and high temperature 27-Al NMR measurements of Al/Al-oxide nanophase composites produced by consolidation of nanoscale Al particles which have been passivated by exposure to air are reported. The Al/Al-oxide nanophase composite material produced has a low density, is electrically conducting and has a hardness much larger than that of metallic Al. High temperature NMR measurements show that the Al metal melts at the same temperature in all the samples, including a large-grained Al metal sample, independent of grain size and without a change in shape of the sample. The results here confirm previous thermal measurements which show that the Al metal melts without grain growth in these materials. On the other hand, the temperature for the onset of rapid atomic diffusion, as estimated from NMR line widths, shows a significant sample dependence. Heated samples exhibit a further factor of five increase in hardness and yet remain electrically conducting.

Suits, B. H.; Apte, P.

1998-03-01

425

Unraveling Al Qaeda's Strategy.  

National Technical Information Service (NTIS)

Gauging the effectiveness of the U.S. strategy to counter international terrorism requires first an understanding of the objectives, ways and means, and implementation strategy of the adversary. In this case, the adversary is Al Qaeda and its network of a...

D. L. Shaffer

2005-01-01

426

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

427

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

428

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

429

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

430

Dar Al Islam Mosque  

Microsoft Academic Search

The mosque and school of the Dar Al Islam Foundation stand on a plateau above the Chama Valley, near the settlement of Abiquiu\\u000a to the north of the capital Sante Fe. The buildings and its inhabitants are part of a project that was initiated in the late\\u000a seventies. The project was born out of a Utopian notion of a liberal

Rudolf Stegers

431

Partnerwahl als konsensuelle Entscheidung  

Microsoft Academic Search

Zusammenfassung  Die vorliegende Studie setzt unsere Analysen der Kontaktierungsprozesse im Online-Dating (KZfSS 2\\/2009) fort. Da Paarbeziehungen\\u000a auf einer konsensuellen Entscheidung für eine gemeinsame Beziehung beruhen, widmet sich der vorliegende Beitrag der Frage,\\u000a wie Männer und Frauen auf Erstkontaktversuche reagieren. Die Datenstruktur von Online-Dating-Börsen bietet eine einzigartige\\u000a Chance, soziologisch im Detail zu rekonstruieren, wie Paarbeziehungen als konsensuelle Wahlhandlung nach und nach entstehen.

Florian Schulz; Jan Skopek; Hans-Peter Blossfeld

2010-01-01

432

Abu Musab Al Suri: Architect of the New Al Qaeda  

Microsoft Academic Search

Drawing on new sources, the authors argue that Abu Musab al Suri (real name Mustafa Setmariam Nasar), now in U.S. custody, is the principle architect of Al Qaeda's post–9\\/11 structure and strategy. His vision, which predated 9\\/11, of transforming Al Qaeda from a vulnerable hierarchical organization into a resilient decentralized movement, was largely the formula Al Qaeda adopted after the

Paul Cruickshank; Mohannad Hage Ali

2007-01-01

433

Wear behavior of Al{sub 2}O{sub 3}-TiCN composite ceramic sliding on stainless steel  

SciTech Connect

It is well known that austenitic stainless steel AISI 302 is relatively difficult to cut. In order to investigate the wear behavior of Al{sub 2}O{sub 3}-TiCN composite ceramic when machining austenitic stainless steels, a block-on-ring tribometer was used to simulate a real machining process. The test results showed that the wear of both the ceramic and the stainless steel increased rapidly with increasing load and speed. The boundary lubrication actions of water and oil used in this test could not reduce the wear of the rubbing materials. Scanning electron microscopy and energy-dispersive x-ray spectroscopy analyses identified material transferred between the ceramic and the stainless steel surfaces in rubbing process. On the one hand, stainless steel transferred on the ceramic surface because of adhesion; on the other, some ceramic fragments caused by microfracture of the ceramic were found to be embedded in the worn stainless steel surface. The wear of Al{sub 2}O{sub 3}-TiCN ceramic sliding against stainless steel was caused primarily by adhesion between the rubbing surfaces and the microfracture of the ceramic.

Zhao, X.Z.; Liu, J.J.; Zhu, B.L.; Luo, Z.B.; Miao, H.Z. [Tsinghua Univ. Beijing (China). Tribology Research Inst.

1996-08-01

434

Frequently Asked Questions about ALS and the ALS Registry  

MedlinePLUS

... on clinical trials? Questions About the ALS Registry Why was the registry created? Who created and is responsible for maintaining the ... Back to Top Questions About the ALS Registry Why was the ALS registry created? The registry was created as a tool to ...

435

DETERMINACIÓN DE LAS RESERVAS DE CARBONO EN LA BIOMASA AÉREA DE SISTEMAS AGROFORESTALES DE Theobroma cacao L. EN EL DEPARTAMENTO DE SAN MARTÌN, PERU DETERMINATION OF CARBON RESERVATIONS IN THE AERIAL BIOMASS OF AGROFORESTRY SYSTEMS OF Theobroma cacao L. IN THE DEPARTMENT OF SAN MARTÌN, PERU  

Microsoft Academic Search

Resumen En este estudio se evaluó la biomasa aérea en seis diferentes sistemas agroforestales de cacao (Theobroma cacao L.) asociado con especies forestales maderables y frutales; con el propósito de conocer el potencial de captura de carbono por cada sistema. El estudio se realizó en dos diferentes sitios ubicados en la región San Martín (provincias de San Martín y Mariscal

Juanita Y. Concha; Julio C. Alegre; Vicente Pocomucha

436

Plasmonen als Lichttransporter: Nanooptik  

NASA Astrophysics Data System (ADS)

Metallische Nanopartikel, Nanodrähte oder Filme können Licht in Oberflächen-Plasmonen einfangen. Dieses Phänomen spielt sich im optischen Nahfeld und im Subwellenlängenbereich ab. Dabei entsteht ein hybrider, optoelektronischer Anregungszustand aus Licht und oszillierenden Leitungselektronen. Metallische Nanopartikel können zum Beispiel als Hilfsantennen die Fluoreszenz von Biomolekülen erheblich verstärken. Das ist für Fluoreszenzsensoren interessant. Experimente zeigen, dass metallische Nanodrähte in Oberflächen-Plasmonen Licht transportieren können. Auf zweidimensionalen, strukturierten Metallfilmen wurden Bauelemente bis hin zum Interferometer für Plasmonen erfolgreich demonstriert. Das junge Feld der Plasmonik könnte wichtige Beiträge zu einer zukünftigen Nanooptik liefern.

Aussenegg, Franz; Ditlbacher, Harald

2006-09-01

437

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

438

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

439

Detecting frontotemporal dysfunction in ALS: utility of the ALS Cognitive Behavioral Screen (ALS-CBS).  

PubMed

Up to half of patients with ALS develop cognitive impairment during the course of the illness. Despite this, there is no simple tool for screening patients in the clinical setting. This study examines the sensitivity, specificity and accuracy of the ALS Cognitive Behavioral Screen (ALS-CBS). We administered the measure to 112 ALS patients, including 31 who also underwent comprehensive neuropsychological testing. Screen results were validated by determining the accuracy against the full battery. Optimal cut-off scores for predicting the correct diagnosis were determined, and mean scores were compared between patients, controls and different diagnostic groups. The results demonstrated that mean cognitive scores differed between ALS and normal controls (p < 0.0001). The cognitive section differentiated ALS-FTD from other ALS patients with 100% accuracy. Cognitively normal ALS patients could be distinguished from those with any cognitive deficit with 71% specificity and 85% sensitivity. A separate behavioral score was significantly lower in the ALS cohort compared to controls (p < 0.0001) and predicted ALS-FTD with 80% sensitivity and 88% specificity. In conclusion, the ALS-CBS can aid in detecting cognitive and behavioral impairment in a clinical setting, although it does not replace formal diagnostic assessment. Further validation with larger sample sizes will clarify its clinical utility. PMID:20433413

Woolley, Susan C; York, Michele K; Moore, Dan H; Strutt, Adriana M; Murphy, Jennifer; Schulz, Paul E; Katz, Jonathan S

2010-05-01

440

Interfacial reactions and oxidation behavior of Al 2O 3 and Al 2O 3/Al coatings on an orthorhombic Ti 2AlNb alloy  

NASA Astrophysics Data System (ADS)

The uniform and dense Al 2O 3 and Al 2O 3/Al coatings were deposited on an orthorhombic Ti 2AlNb alloy by filtered arc ion plating. The interfacial reactions of the Al 2O 3/Ti 2AlNb and Al 2O 3/Al/Ti 2AlNb specimens after vacuum annealing at 750 °C were studied. In the Al 2O 3/Ti 2AlNb specimens, the Al 2O 3 coating decomposed significantly due to reaction between the Al 2O 3 coating and the O-Ti 2AlNb substrate. In the Al 2O 3/Al/Ti 2AlNb specimens, a ?-TiAl layer and an Nb-rich zone came into being by interdiffusion between the Al layer and the O-Ti 2AlNb substrate. The ?-TiAl layer is chemically compatible with Al 2O 3, with no decomposition of Al 2O 3 being detected. No internal oxidation or oxygen and nitrogen dissolution zone was observed in the O-Ti 2AlNb alloy. The Al 2O 3/Al/Ti 2AlNb specimens exhibited excellent oxidation resistance at 750 °C.

Li, H. Q.; Wang, Q. M.; Gong, J.; Sun, C.

2011-02-01

441

„Leistung“ als Aktion und Präsentation  

Microsoft Academic Search

\\u000a Zusammenfassungen  Die sprachanalytische Untersuchung des Begriffs „Leistung“ führt zu der Konzeption einer „Philosophie der Leistung“ als einer\\u000a Theorienormativer Aussagen über „Leistung“. Handlungen werden anhand bestimmter Kriterien als „Leistungen“ identifiziert; es kommt daher der Präsentation dieser Aktionen\\u000a als „Leistungen“ Bedeutung zu: Eine „Leistung“ besteht immer aus einer „Aktions-“ und einer „Präsentations-Leistung“. Insbesondere\\u000a die „Präsentations-Leistung“ erfüllt eine entscheidende Funktion bei der Konstitution von

Gunter Gebauer

1972-01-01

442

Microstructures and properties of Al 2O 3\\/Al–AlN composites by pressureless infiltration of Al-alloys  

Microsoft Academic Search

Al alloys were infiltrated into Al2O3 preforms in N2 and N2– 2% H2 gas mixture in the temperature regime of 900–1200°C. The kinetics of nitridation during infiltration were continuously monitored by recording weight gained during infiltration of the preform. The weight gains that are attributed to the formation of AlN in the matrix were observed to increase with processing temperature.

N Nagendra; B. S Rao; V Jayaram

1999-01-01

443

Al Qaeda's Scorecard: A Progress Report on Al Qaeda's Objectives  

Microsoft Academic Search

Terrorism scholars are divided over whether terrorism is an effective tactic. Disagreement derives from the fact that the objectives of terrorist groups are often highly contested. Nowhere is this clearer than in contemporary statements on Al Qaeda. This article explores the most common interpretations for why Al Qaeda attacked the United States on 11 September 2001, and then analyzes their

Max Abrahms

2006-01-01

444

Cyclic response-electrochemical interaction in mono- and polycrystalline AISI 316L stainless steel in H[sub 2]SO[sub 4] solution-I. The influence of mechanical strain on the transient dissolution behavior during corrosion fatigue  

SciTech Connect

Mono-[gamma] and polycrystalline specimens of an AISI stainless steel were cycled in a 1N H[sub 2]SO[sub 4] solution under different potentials. The correspondence between strain wave form and transient current curve has been studied. Transient current, which has been measured with out-of-the-ordinary resolution, has been demonstrated to have two components: the current associated with plastic strain (CAPS) and the current associated with elastic strain (CAES), caused exclusively by plastic deformation and elastic deformation respectively. The strong interaction between the environment and the fresh area at slip steps is the main cause of the CAPS. The wave forms of the CAPS is affected by selective dissolution of iron, tension compression asymmetry, and the fatigue cracking process. The CAES is produced by the variation in the energetic status of the surface, and possibly by the charging effect of the electric double layer.

Li, Y.F.; Farrington, G.C.; Laird, C. (Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering)

1993-03-01

445

The influence of cold-work level on the irradiation creep and swelling of AISI 316 stainless steel irradiated as pressurized tubes in the EBR-II fast reactor  

NASA Astrophysics Data System (ADS)

Pressurized tubes of AISI 316 stainless steel irradiated in the P-1 experiment in the EBR-II fast reactor have been measured to determine the dependence of irradiation-induced strains resulting from plastic deformation, irradiation creep, void swelling and precipitation. It is shown that the Soderberg relation predicting no axial creep strains in biaxially-loaded tubes is correct for both plastic and creep strains. Swelling strains are shown to be isotropically distributed both for stress-free and stress-affected swelling, while precipitation strains are somewhat anisotropic in their distribution. When corrected for stress-enhancement of swelling, the derived irradiation creep strains appear to be identical for both annealed and 20% cold-worked specimens, and also for tubes strained by rise to power increases in pressure. For relatively small creep strains it is often difficult to separate the creep and non-creep components of deformation.

Gilbert, E. R.; Garner, F. A.

2007-08-01

446

AL Amyloidosis with Renal Involvement  

Microsoft Academic Search

Primary (AL amyloidosis) is a systemic disease characterized by an amyloid deposition process in many organs, with unsatisfactory survival of patients. The monoclonal light chains form the fibrils that deposit and accumulate in tissues. Renal involvement is very frequent in AL amyloidosis and could lead to development of nephrotic syndrome followed by the renal failure in many cases. Classic therapeutic

Romana Ryšavá

2007-01-01

447

AlN Substrate Applications.  

National Technical Information Service (NTIS)

The types of presently available AlN substrates are outlined along with the precautions to be taken in using them. Also discussed in detail are the factors to be considered in planning the introduction of AlN substrates and the structures, properties and ...

N. Iwase

1988-01-01

448

Al Qaeda: Ideology and action  

Microsoft Academic Search

Serious threats to global order are said to emanate from Al Qaeda, exemplified by bombings and multiple deaths in, inter alia, Bali, Dar es Salaam, Istanbul, Nairobi, New York and Madrid. These outrages raise the question about the ideological assumptions and goals of Al Qaeda – given that the majority of the dead were not Jews or Christians, but Muslims. What

JEFFREY HAYNES

2005-01-01

449

How al Qaeda lost Iraq  

Microsoft Academic Search

Al Qaeda in Iraq (AQI) has suffered a grave setback in the context of its ongoing campaign there. Since late 2006 Sunni tribal militias working in conjunction with Coalition forces have decimated AQI's ranks, and the organisation has been largely expelled from its former sanctuaries in western Iraq. This article seeks to explain the causes of al Qaeda's defeat with

Andrew Phillips

2009-01-01

450

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

451

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

452

The Advanced Launch System (ALS)  

NASA Astrophysics Data System (ADS)

The Advanced Launch System (ALS) is an unmanned vehicle that will achieve low hardware cost by using a reusable booster stage which flies back to the launch site, and a core stage in which the rocket engines and redundant avionics are in a module that is returned to earth and recovered for reuse. The booster's utilization of liquid propellant instead of solid propellant will help lower the consumable costs. The ALS also includes launch processing and flight control facilities, necessary support equipment, and ground- and flight-operations infrastructure. The ALS program studies show that, through the ALS, the United States can launch a major Mars initiative economically and with confidence. It is estimated that the objective ALS can be operational in the late 1990s.

Eldred, Charles H.

453

Stimulated emission in AlGaN/AlGaN quantum wells with different Al content  

NASA Astrophysics Data System (ADS)

Stimulated emission (SE) is studied in AlGaN/AlGaN multiple quantum wells (MQWs) with different Al content grown on sapphire substrate. The spectra of spontaneous and stimulated emission and their transformations with increasing temperature as well as stimulated emission thresholds were measured in the temperature range from 8 to 300 K. Phonon-assisted band broadening in low-Al-content MQWs and double-scaled potential profile in high-Al-content MQWs were observed in the samples and linked with carrier localization conditions. The temperature dependence of the stimulated emission threshold was similar in the samples where the stimulated transitions occur between extended states and in the samples where the transitions occur in localized states. The stimulated emission threshold depends predominantly on the density of nonradiative recombination centers.

Mickevi?ius, J.; Jurkevi?ius, J.; Kazlauskas, K.; Žukauskas, A.; Tamulaitis, G.; Shur, M. S.; Shatalov, M.; Yang, J.; Gaska, R.

2012-02-01

454

Al Cu Texture Enhancement by Underlayer Texture  

Microsoft Academic Search

Al Cu layered films and interconnections (Al\\/underlayers) were fabricated and investigatedto observe the effects of underlayer texture on Al texture development and of Al texture onelectromigration resistance. Al(111) texture was enhanced by controlling Ti and TiNunderlayer textures. Values of full width at half maximum for Al(111) rocking curves rangedfrom 0.64° to 4.7° for Al Cu films grown on Ti, TiN\\/Ti,

Tsutomu Sasaki; Hitoshi Dohnomae

1998-01-01

455

Comparing the Thermodynamic Behaviour of Al(1)+ZrO2(s) to Al(1)+Al2O3(s).  

National Technical Information Service (NTIS)

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 dire...

E. Copland

2004-01-01

456

Genetic inroads in familial ALS.  

PubMed

Amyotrophic lateral sclerosis (ALS) is a common neurodegenerative disease causing cell death of motor neurons and progressive muscle weakness. The disease is familial in ten percent of cases, of which one-fifth are due to mutations in the gene encoding Cu/Zn superoxide dismutase (SOD1). Two papers in this issue of Nature Genetics describe homozygous mutations in a new gene on chromosome 2q33 in 4 families of Arabian origin with a rare form of juvenile onset ALS (ALS2). The predicted protein structure has domains homologous to GTPase regulatory proteins, and both the types of mutation and the pattern of inheritance suggest that motor neuron degeneration is the result of a loss of function. Further work will determine the relevance of this breakthrough to other, more common forms of ALS. PMID:11586285

Shaw, P J

2001-10-01

457

Transcranial magnetic stimulation in ALS  

PubMed Central

Objective: To investigate transcranial magnetic stimulation (TMS) measures as clinical correlates and longitudinal markers of amyotrophic lateral sclerosis (ALS). Methods: We prospectively studied 60 patients with ALS subtypes (sporadic ALS, familial ALS, progressive muscular atrophy, and primary lateral sclerosis) using single pulse TMS, recording from abductor digiti minimi (ADM) and tibialis anterior (TA) muscles. We evaluated three measures: 1) TMS motor response threshold to the ADM, 2) central motor conduction time (CMCT), and 3) motor evoked potential amplitude (correcting for peripheral changes). Patients were evaluated at baseline, compared with controls, and followed every 3 months for up to six visits. Changes were analyzed using generalized estimation equations to test linear trends with time. Results: TMS threshold, CMCT, and TMS amplitude correlated (p < 0.05) with clinical upper motor neuron (UMN) signs at baseline and were different (p < 0.05) from normal controls in at least one response. Seventy-eight percent of patients with UMN (41/52) and 50% (4/8) of patients without clinical UMN signs had prolonged CMCT. All three measures revealed significant deterioration over time: TMS amplitude showed the greatest change, decreasing 8% per month; threshold increased 1.8% per month; and CMCT increased by 0.9% per month. Conclusions: Transcranial magnetic stimulation (TMS) findings, particularly TMS amplitude, can objectively discriminate corticospinal tract involvement in amyotrophic lateral sclerosis (ALS) from controls and assess the progression of ALS. While central motor conduction time and response threshold worsen by less than 2% per month, TMS amplitude decrease averages 8% per month, and may be a useful objective marker of disease progression. GLOSSARY ADM = abductor digiti minimi; ALS = amyotrophic lateral sclerosis; ANOVA = analysis of variance; CI = confidence interval; CMAP = compound motor action potential; CMCT = central motor conduction time; DTR = deep tendon stretch reflex; fALS = familial ALS; GEE = generalized estimation equations; LMN = lower motor neuron; MEP = motor evoked potential; PLS = primary lateral sclerosis; PMA = progressive muscular atrophy; sALS = sporadic ALS; TA = tibialis anterior; TMS = transcranial magnetic stimulation; UMN = upper motor neuron.

Floyd, A G.; Yu, Q P.; Piboolnurak, P; Tang, M X.; Fang, Y; Smith, W A.; Yim, J; Rowland, L P.; Mitsumoto, H; Pullman, S L.

2009-01-01

458

MADINAT AL-ZAHRAí: INVESTIGACI\\  

Microsoft Academic Search

The virtual reconstruction of the archeological site of Mad inat al-Zahraí in CÛrdoba (Spain) has permitted a new approach to the study and comprehension of this palatine city as well as to the typologies of Islamic architecture in Al-Andalus during the 10th century. Starting from fieldwork and from a photogrammetric survey of the site, the digital model has become a

Antonio Almagro Gorbea; Ana Almagro Vidal

459

Befähigungsgerechtigkeit als Ermöglichung gesellschaftlicher Inklusion  

Microsoft Academic Search

Soziale Gerechtigkeit gilt vielen — vor allem in Deutschland — noch immer als ein zuhöchst attraktiver Wert politischen Zusammenlebens,\\u000a der auch als gesellschaftliche Norm zu etablieren sei. Nicht nur in der politischen Rhetorik, sondern auch in der Sozialtheorie\\u000a und politischen Philosophie schillert der Begriff vielfach. Er ringt vor dem anthropologisch nicht zu bestreitenden Spannungsverhältnis\\u000a von Kooperationswilligkeit und Konkurrenz- und Konfliktbeladenheit

Peter Dabrock

460

Befähigungsgerechtigkeit als Ermöglichung gesellschaftlicher Inklusion  

Microsoft Academic Search

Soziale Gerechtigkeit gilt vielen – vor allem in Deutschland – noch immer als ein zuhöchst attraktiver Wert politischen Zusammenlebens,\\u000a der auch als gesellschaftliche Norm zu etablieren sei. Nicht nur in der politischen Rhetorik, sondern auch in der Sozialtheorie\\u000a und politischen Philosophie schillert der Begriff vielfach. Er ringt vor dem anthropologisch nicht zu bestreitenden Spannungsverhältnis\\u000a von Kooperationswilligkeit und Konkurrenz- und Konfliktbeladenheit

Peter Dabrock

461

Influence of the substrate bias voltage on the crystallographic structure and mechanical properties of Ti6Al4V coatings deposited by rf magnetron  

NASA Astrophysics Data System (ADS)

Physical and mechanical properties of pure titanium are improved when the material is mixed with aluminum and vanadium at specific concentrations. Specifically, the alloy composed by 90% of titanium, 6% of aluminum and 4% of vanadium (Ti-6Al-4V) is highly resistant to fatigue and corrosion titanium and their alloys can be deposited by two techniques: Chemical Vapor Deposition (CVD) and Physical Vapor Deposition (PVD). However, some problems are generated when carbonated steel substrates are used under the CVD technique, mainly because those substrates lost its carbon as a result of the high substrate temperature used during the deposition process. Alternatively, PVD (magnetron sputtering, ion plating) is a low temperature substrate process and also has the advantage that substrate bias can promote structure refinement through resputtering effects.Substrate bias influence on the crystalline structure of Ti6Al4V thin films prepared by rf magnetron sputtering are presented in this work. Samples were grown onto common glass and AISI 420 steel substrates using a Ti6Al4V (99.9 %) target. Substrate bias was varied from -100 V to -200 V. Samples were characterized by X-ray Diffraction (XRD), Energy Dispersive X-ray Spectroscopy (EDXS), Scanning Electron Microscopy (SEM), and Atomic Force Microscopy (AFM). Thin films stoichiometry were studied by EDX in agreement with the Ti-6Al-4V target. Finally, the studies of the mechanical behavior of the films on steel showed that the hardness increased 1100 Knoop when the bias voltage is raised to -160 V.

Alfonso, J. E.; Pacheco, Fernando; Castro P., Alvaro; Torres, J.

2005-08-01

462

FTD and ALS: genetic ties that bind.  

PubMed

Curiously, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD), seemingly disparate neurodegenerative disorders, can be inherited together. Two groups (DeJesus-Hernandez et al. and Renton et al.) show that the long sought after ALS/FTD mutation on chromosomal region 9p is a hexanucleotide expansion in C90RF72. These studies, plus a study on X-linked ALS/FTD, provide molecular starting points for identifying pathways that link ALS and FTD pathogenesis. PMID:22017980

Orr, Harry T

2011-10-20

463

AL1-dependent repression of transcription enhances expression of Tomato golden mosaic virus AL2 and AL3  

PubMed Central

Studies using Nicotiana benthamiana protoplasts have determined that repression of upstream transcription by AL1 protein enhances AL2 and AL3 expression in Tomato golden mosaic virus (TGMV). Mutations resulting in the inability of TGMV AL1 protein to associate with its cognate binding site, result in a decrease in both AL2 and AL3 expression. Reduced expression correlates with an increase in transcription from the AL62 start site, and decreased transcription from downstream initiation sites (AL1935 and AL1629) present within the AL1 coding region. The results demonstrate that, in a tobacco protoplast system, repression of AL62 transcription, regulated through binding of AL1 protein to sequences in the origin of replication, is required prior to AL2 and AL3 gene expression from the AL1935 and AL1629 viral transcripts. This provides a mechanism to regulate expression of AL2, which is involved in suppression of host defense responses and is required for late gene expression.

Shung, Chia-Yi; Sunter, Garry

2010-01-01

464

Muqtada al-Sadr: How to Demilitarize al-Sadr.  

National Technical Information Service (NTIS)

Muqtada al-Sadr has been one of the most influential individuals in Iraq since the U.S. invasion in March 2003. His Mahdi Army has actively confronted coalition forces and engaged in ethnic cleansing that has resulted in the displacement of thousands of I...

M. E. Hollinger

2009-01-01

465

Powder Metallurgy Processing of Dual Phase Al Rich Fe-Al Intermetallics.  

National Technical Information Service (NTIS)

A powder metallurgy technique was used to fabricate two different dual-phase Al-rich Fe-Al intermetallics, namely, FeAl2-Fe2Al5 and FeAl3-Fe2Al5. Powders were first produced by inert gas atomization, and then subsequently consolidated by hot pressing at 1...

Y. L. Jeng R. Hayes J. Wolfenstine E. J. Lavernia

1995-01-01

466

Triple A syndrome mimicking ALS.  

PubMed

We report a 22-year-old female who presented with distal muscular atrophy and weakness in all limbs for two years. Reflexes were symmetrically brisk and electrodiagnostic studies were consistent with upper and lower motor neuron involvement. A diagnosis of juvenile ALS was considered. However, surgery for achalasia in childhood and identification of alacrima and adrenal insufficiency suggested Triple A syndrome accompanied by neurological symptoms. Sequencing of the AAAS gene identified compound heterozygous mutations confirming the clinical diagnosis and demonstrating that Triple A syndrome can mimic juvenile ALS. PMID:18615337

Strauss, Maria; Koehler, Katrin; Krumbholz, Manuela; Huebner, Angela; Zierz, Stephan; Deschauer, Marcus

2008-10-01

467

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

468

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

469

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 perm...

L. Niu

2008-01-01

470

Interview with Mumna Al Banchaabouchi  

NSDL National Science Digital Library

An interview with Dr Mumna Al Banchaabouchi, researcher in the Mouse Phenotyping Core at EMBL in Monterotondo Italy. This video is two minutes and 55 seconds in length, and available in Quicktime (25 MB) and Windows Media Player (29 MB). All Stem Cells videos are located at: http://www.hhmi.org/biointeractive/stemcells/video.html.

Howard Hughes Medical Institute (Howard Hughes Medical Institute;)

2007-03-31

471

Cómo hacer frente al cáncer  

Cancer.gov

Existen muchos recursos de ayuda y apoyo para las personas con cáncer, sus familiares y amigos. Infórmese sobre las reacciones psicológicas al cáncer y la forma de hacer frente a estas situaciones. Conozca los servicios que ofrecen las comunidades locales y las organizaciones nacionales para ayudarle con los diferentes aspectos del tratamiento y la recuperación del cáncer.

472

Al Qaeda: A Different Diagnosis  

Microsoft Academic Search

When doubt and confusion reign, when things are--or look--complicated, one should revert to fundamental questions. What is Al Qaeda? This is the question addressed by this article. But as a first step, and in a broader perspective, the real danger in the world today is defined.?

XAVIER RAUFER

2003-01-01

473

Dry sliding wear behaviour of Al–12Si and Al–12Si–3Cu cast alloys  

Microsoft Academic Search

This paper attempts to investigate the influence of the microstructural changes on the dry sliding wear behaviour of Al–12Si and Al–12Si–3Cu cast alloys by grain refinement (Al–1Ti–3B), modification (Al–10Sr) and combined action of both (Al–1Ti–3B+Al–10Sr). Results indicate that combined grain refined and modified Al–12Si–3Cu cast alloys have microstructures consisting of uniformly distributed ?-Al grains, eutectic Al–silicon and fine CuAl2 particles

K. G. Basavakumar; P. G. Mukunda; M. Chakraborty

2009-01-01

474

Molecular Dynamics Study of Velocity Dependence of Sliding Friction at Al/Al and Al2O3/Al2O3 Interface  

NASA Astrophysics Data System (ADS)

Using the newly developed reactive force field, the static and kinetic friction behavior of Al/Al (flat and rough), Al2O3/Al2O3 (commensurate and incommensurate) interfaces have been studied by molecular dynamics simulations. It is found that the commensurate Al2O3/Al2O3 interface has higher friction than incommensurate Al2O3/Al2O3 interface. For both interfaces, at lower velocities, friction exhibits dry friction, whereas above a critical speed, the velocity dependence follows a viscous relation. For Al/Al flat interface, only viscous friction is observed. Roughness on the surface would increase friction and change velocity dependence. The simulation results indicate that the different behaviors of velocity dependence are from the interfacial interaction or potential surface for these friction samples. The origin of static friction is also discussed.

Zhang, Qing; Cagin, Tahir; Goddard, William A.; Qi, Yue; Hector, Louis G.

2004-03-01

475

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

476

Thermal conductance of a pressed Al-Al contact  

NASA Astrophysics Data System (ADS)

Thermal conductance of a screw-fastened joint between two blocks of Al-alloys has been measured. An AlMg4.5Mn-block, the end of which is cooled by liquid helium, constitutes the upper part of the sample and the contact is formed at the face surface of a cylindrical extension of that block onto which a cylinder, made of AlMgSi1, is pressed by means of a copper-nickel screw. Pressing of the contact was carried out at room temperature by applying a defined torque, M, to the fastening screw. Three samples of the same shape but with differently treated surfaces of contact (machined flat, electro-chemically polished, with gold plated contacts) were studied. The results showed that the machined flat surfaces yield the best contact and that the contact conductance (measured in the range 4.2 K to 1.8 K) of all samples increased with increasing torque. In addition to thermal measurements, a study of the electrical conductance would be very interesting to determine the different contributions of phonon and electron heat conduction by means of the Wiedemann-Franz law. The work is useful for the GIRL (German Infra-Red Laboratory) space experiment.

Wanner, M.

1981-01-01

477

Cyclic response-electrochemical interaction in mono- and polycrystalline AISI 316L stainless steel in H[sub 2]SO[sub 4] solution-III. Potential dependence of the mechanical behavior during corrosion fatigue  

SciTech Connect

Measurements of mechanical parameters and surface examinations have been carried out on mono- and polycrystalline specimens of an AISI 316L stainless steel which were cycled in a 1N H[sub 2]SO[sub 4] solution. Analysis was made in relation to both the number of cycles and the applied potentials. The environment was found to have no influence on such bulk properties as the softening rate and flow stress, because the oxide film on the stainless steel is very thin. The magnitude of the strain localization was enhanced by preferential dissolution of atoms in the slip bands, a tendency which decreased with increase in potential. Crack nucleation within the slip bands was caused by either the high dissolution rate imposed by the applied potential (in the corrosion and the transition regions) or by the galvanic effect (in the passive I region). General corrosion was found to have major effects on the crack propagation process in both the corrosion region, where blunting inhibited propagation, and the transition region where corrosion-stimulated sharpening promoted propagation. In the passive II region, environment-assisted strain localization and the galvanic effect were prevented by the stable passive film and the rapid passivation reaction.

Li, Y.F.; Farrington, G.C.; Laird, C. (Univ. of Pennsylvania, Philadelphia, PA (United States). Dept. of Materials Science and Engineering)

1993-03-01

478

Dissimilar metal joining of aluminum alloy to galvanized steel with Al–Si, Al–Cu, Al–Si–Cu and Zn–Al filler wires  

Microsoft Academic Search

Aluminum alloy sheets were lap joined to galvanized steel sheets by gas tungsten arc welding (GTAW) with Al–5% Si, Al–12% Si, Al–6% Cu, Al–10% Si–4% Cu and Zn–15% Al filler wires. Different amounts of Si, Cu and Zn were introduced into the weld through different filler wires. The effects of alloying elements on the microstructure in the weld and tensile

Honggang Dong; Wenjin Hu; Yuping Duan; Xudong Wang; Chuang Dong

479

The effect of Si in Al-alloy on electromigration performance in Al filled vias  

NASA Astrophysics Data System (ADS)

Electromigration performance of vias filled with Al-Si-Cu alloys on Ti glue layers was investigated in comparison with W-stud vias. In Al-Si-Cu filled vias, voids were formed at only a few locations in the test structure, while voids were formed at every via in W-stud via chains. It is supposed that Al moves through the Al-Si-Cu via during electromigration in spite of the existence of a glue layer at the via bottom. This phenomenon was observed only in the vias filled with Al-Si-Cu alloy. Al movement was prohibited in Al-Cu filled vias. In Al-Si-Cu filled vias, an Al-Ti-Si alloy was formed at the via bottom while Al3Ti was formed at Al-Cu filled vias. Al is speculated to move through this Al-Ti-Si alloy during electromigration.

Kageyama, Makiko; Hashimoto, Keiichi; Onoda, Hiroshi

1998-01-01

480

Growth processes in molecular beam expitaxy of single-crystal Al layers on AlAs  

Microsoft Academic Search

The molecular beam epitaxial growth processes of Al single-crystal layers deposited at room temperature on As-stabilized and on Al-stabilized AlAs surfaces are investigated insitu using reflection high-energy electron diffraction (RHEED). The epitaxy relationship of Al with the underlying AlAs is (011)[100]Al\\/\\/(001)[110]AlAs irrespective of the surface stoichiometry of AlAs. Detailed RHEED investigation suggests that the initially deposited two one-monolayer-thick Al layers

Hiroaki Nakahara; Hirofumi Matuhata; Yasumasa Okada; Tateki Kurosu; Masamori Iida; Takafumi Yao

1991-01-01

481

Ion beam mixing in the Al\\/NixAl1 - x\\/Ni system  

Microsoft Academic Search

Thin-film alloy samples of Al\\/NixAl1?x\\/Ni (x=0.75, 0.5, 0.25) were irradiated at room temperature and at 160 °C with 280 and 560 keV Xe ions to a dose of 1.1×1016 Xe ions\\/cm2. The samples were analyzed by Rutherford backscattering spectrometry. In the Al\\/Ni3Al\\/Ni configuration the Ni3Al layer mixes more strongly with Al than with Ni. In the Al\\/NiAl\\/Ni samples, the NiAl

E. Rimini; M. Nastasi; J. Liu; J. C. Barbour; J.-P. Hirvonen; J. W. Mayer

1986-01-01

482

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

483

Photoemission study of Al adlayers on Mn  

NASA Astrophysics Data System (ADS)

Al overlayers on Mn, studied by photoemission spectroscopy, show a large lowering of the Al 2p core-level binding energy by 0.5 eV at submonolayer (0.1 ML) coverage. The binding energy increases with coverage and reaches the bulk Al value at ?1.3 ML. The Al 2p core-level spectrum exhibits extra components related to the different chemical environment at the interface, which decrease in intensity with increasing Al coverage. The Al related plasmon loss features appear above 1 ML. The present results are explained by a strong Al s,p-Mn 3d hybridization at the submonolayer coverage due to interface alloying, whose influence on the spectra is dominated by metallic bonding in the Al layer as coverage increases. The valence-band spectra demonstrate systematic suppression of Mn 3d-like states and emergence of a parabolic free-electron-like Al density of states.

Dhaka, R. S.; Shukla, A. K.; Horn, K.; Barman, S. R.

2011-12-01

484

Synthesis of AlN/Al Polycrystals along with Al Nanoparticles Using Thermal Plasma Route  

SciTech Connect

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 AlN crystal and aluminium nanoparticles was done by using the x-ray diffraction method, scanning electron microscopy and transmission electron microscopy.

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)

2011-07-15

485

The strengthening effect of Al 3Ti in high temperature deformation of Al–Al 3Ti composites  

Microsoft Academic Search

A series of Al–Al3Ti composites with systematic variation of Al3Ti content were prepared by mechanical alloying. Microstructural observations have indicated that among these composites, the only distinct variable is the Al3Ti content, while the other microstructural variables are essentially the same. The high temperature (623–773K) deformation behavior of these composites was found to be similar to that of dispersion-hardened aluminum.

S. H. Wang; P. W. Kao

1998-01-01

486

Processing of In-Situ Al-AlN Metal Matrix Composites via Direct Nitridation Method.  

National Technical Information Service (NTIS)

The primary objective of this research was to provide a fundamental understanding of the processing science necessary to fabricate the Aluminum Nitride (AlN) reinforced Aluminum (Al) composites via direct nitration of the Al alloy melt. From the thermodyn...

K. S. Shin Y. S. Kim N. J. Kim

1998-01-01

487

Investigation of Wear Anisotropy in a Severely Deformed Al-Al3Ti Composite  

NASA Astrophysics Data System (ADS)

In the current investigation, Al-Al3Ti composite was processed by equal channel angular pressing (ECAP). ECAP was carried out using routes A and BC up to eight passes of deformation. It was observed that increasing the number of ECAP passes causes fragmentation of Al3Ti platelet particles and decreases their sizes compared to their original sizes in the undeformed Al-Al3Ti specimens. Moreover, the microstructure of route A-ECAPed Al-Al3Ti composite samples showed a strong alignment of the fragmented Al3Ti particles parallel to the pressing axis. On the other hand, ECAPed Al-Al3Ti alloy specimens by route BC have a relatively homogeneous distribution of Al3Ti particles. Because of the platelet Al3Ti particle fragmentation by ECAP, all the ECAPed specimens showed small anisotropy in their wear property in spite of this observed anisotropic microstructure induced by route A-ECAP.

El-Hadad, Shimaa; Sato, Hisashi; Watanabe, Yoshimi

2012-05-01

488

The preparation and mechanical properties of Al 2O 3\\/Ni 3Al composites  

Microsoft Academic Search

Al2O3\\/Ni3Al composites containing 10vol% of intermetallic phase have been studied in this work. Ni3Al particles with two different morphologies were added to the alumina matrix, viz. Ni3Al as-prepared (AP) by atomization and Ni3Al finely ball-milled (BM) in argon for 96h. Both AP and BM composites were prepared by pressureless sintering at a relatively low temperature. As-prepared Ni3Al powder was also

Vincenzo M Sglavo; Francesco Marino; Bing-Rong Zhang

1999-01-01

489

Effects of the Al content on pore structures of porous TieAl alloys  

SciTech Connect

Porous TieAl alloys with different nominal compositions were fabricated through a reactive synthesis of Ti and Al elemental powders. It has been found that the pore parameters vary with the Al contents, indicating that the nature of the pores can be manipulated through changing the Al contents. In addition, detailed structural characterizations showed that the fabricated porous TieAl alloys can have three crystalline phases (i.e., a2-Ti3Al, g-TiAl, and TiAl3) when using different compositions. The fundamental reasons behind these phenomena have been explored.

Jaing, Y [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China; He, Y H [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China; Xu, N P [Membrane Science and Technology Research Center, Nanjing University of Technology, Nanjing 210009, C; Zou, J [School of Engineering and Centre for Microscopy and Microanalysis, The University of Queensland, QLD; Huang, B [State Key Laboratory for Powder Metallurgy, Central South University, Changsha 410083, China; Lui, C T [Oak Ridge National Laboratory (ORNL)

2008-01-01

490

Phosphorus Enhances Al Resistance in Al-resistant Lespedeza bicolor but not in Al-sensitive L. cuneata Under Relatively High Al Stress  

PubMed Central

Background and Aims Aluminium (Al) toxicity and phosphorus (P) deficiency often co-exist in acidic soils and limit crop production worldwide. Lespedeza bicolor is a leguminous forage species that grows very well in infertile, acidic soils. The objective of this study was to investigate the effects of Al and P interactions on growth of Lespedeza and the distributions of Al and P in two different Al-resistant species, and to explore whether P can ameliorate the toxic effect of Al in the two species. Methods Two species, Lespedeza bicolor and L. cuneata, were grown for 30 d with alternate Al and P treatments in a hydroponics system. Harvested roots were examined using a root-system scanner, and the contents of Al, P and other nutrient elements in the plants were determined using inductively coupled plasma-atomic emission spectroscopy (ICP-AES). Haematoxylin staining was used to observe the distribution of Al in the roots of seedlings. After pre-culture with or without P application, organic acids in the exudates of roots exposed to Al were held in an anion-exchange resin, eluted with 2 m HCl and then analysed using high-performance liquid chromatography (HPLC). Key Results Lespedeza bicolor exhibited a stronger Al resistance than did L. cuneata; Al exclusion mechanisms may mainly be responsible for resistance. P application alleviated the toxic effect of Al on root growth in L. bicolor, while no obvious effects were observed in L. cuneata. Much less Al was accumulated in roots of L. bicolor than in L. cuneata after P application, and the P contents in both roots and shoots increased much more for L. bicolor than for L. cuneata. Lespedeza bicolor showed a higher P/Al ratio in roots and shoots than did L. cuneata. P application decreased the Al accumulation in root tips of L. bicolor but not in L. cuneata. The amount of Al-induced organic acid (citrate and malate) exudation from roots pre-cultured with P was much less than from roots without P application; no malate and citrate exudation was detected in L. cuneata. Conclusions P enhanced Al resistance in the Al-resistant L. bicolor species but not in the Al-sensitive L. cuneata under relatively high Al stress, although P in L. cuneata might also possess an alleviative potential. Enhancement of Al resistance by P in the resistant species might be associated with its more efficient P accumulation and translocation to shoots and greater Al exclusion from root tips after P application, but not with an increased exudation of organic acids from roots.

Sun, Qing Bin; Shen, Ren Fang; Zhao, Xue Qiang; Chen, Rong Fu; Dong, Xiao Ying

2008-01-01

491

Nonstoichiometry of Al-Zr intermetallic phases.  

National Technical Information Service (NTIS)

Nonstoichiometry of metastable cubic (beta)(prime) and equilibrium tetragonal (beta) Al-Zr intermetallic phases of the nominal composition Al(sub 3)Zr in Al-rich alloys has been extensively studied. It is proposed that the ''dark contrast'' of (beta)(prim...

V. Radmilovic G. Thomas

1994-01-01

492

Rethinking ALS: The FUS about TDP43  

Microsoft Academic Search

Amyotrophic lateral sclerosis (ALS) is an adult-onset neuro- degenerative disorder in which premature loss of motor neu- rons leads to fatal paralysis with a typical disease course of 1 to 5 years. Most forms of ALS are sporadic, but ~10% of patients have an inherited familial form of the disease and a clear family history. Understanding of ALS pathogenesis began

Clotilde Lagier-Tourenne; Don W. Cleveland

2009-01-01

493

Correlation between Al2O3 particles and interface of Al Al2O3 coatings by cold spray  

NASA Astrophysics Data System (ADS)

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 10:1 wt% and 1:1 wt%. Al2O3 particles were successfully incorporated into the soft metal matrix of Al. It was found that crater formation between the coatings and substrate, which is typical characteristic signature of cold spray could be affected by initial starting Al2O3 particles. In addition, when the large hard particles of fused Al2O3 were employed, the deep and big craters were generated at the interface between coatings and hard substrates. In the case of pure soft metal coating such as Al on hard substrate, it is very hard to get proper adhesion due to lack of crater formation. Therefore, the composite coating would have certain advantages.

Lee, Ha Yong; Jung, Se Hun; Lee, Soo Yong; You, Young Ho; Ko, Kyung Hyun

2005-12-01

494

Long term corrosion on T91 and AISI1 316L steel in flowing lead alloy and corrosion protection barrier development: Experiments and models  

NASA Astrophysics Data System (ADS)

Considering the status of knowledge on corrosion and corrosion protection and especially the need for long term compatibility data of structural materials in HLM a set of experiments to generate reliable long term data was defined and performed. The long term corrosion behaviour of the two structural materials foreseen in ADS, 316L and T91, was investigated in the design relevant temperature field, i.e. from 300 to 550 °C. The operational window of the two steels in this temperature range was identified and all oxidation data were used to develop and validate the models of oxide scale growth in PbBi. A mechanistic model capable to predict the oxidation rate applying some experimentally fitted parameters has been developed. This model assumes parabolic oxidation and might be used for design and safety relevant investigations in future. Studies on corrosion barrier development allowed to define the required Al content for the formation of thin alumina scales in LBE. These results as well as future steps and required improvements are discussed. Variation of experimental conditions clearly showed that specific care has to be taken with respect to local flow conditions and oxygen concentrations.

Weisenburger, A.; Schroer, C.; Jianu, A.; Heinzel, A.; Konys, J.; Steiner, H.; Müller, G.; Fazio, C.; Gessi, A.; Babayan, S.; Kobzova, A.; Martinelli, L.; Ginestar, K.; Balbaud-Célerier, F.; Martín-Muñoz, F. J.; Soler Crespo, L.

2011-08-01

495

Nanoscale interaction layer at the interface between Al films and SiO2 substrates of Al/AlOx/Al Josephson tunnel junctions  

NASA Astrophysics Data System (ADS)

An interaction layer is found at the Al/SiO2 interface in Al/AlOx/Al tunnel junctions grown on SiO2 substrates. The amorphous intermixing layer has an average thickness of about 5 nm. We present the detailed structure of this interfacial layer as determined by transmission electron microscopy. The layer contains alumina with aluminum being octahedrally coordinated according to electron energy loss spectroscopy analysis rather than tetrahedrally coordinated, where the latter coordination is the most common type in amorphous alumina. Depth profiles of the Al-O and Si-O bonding characteristics were also investigated using energy loss near edge structure.

Zeng, L. J.; Greibe, T.; Nik, S.; Wilson, C. M.; Delsing, P.; Olsson, E.

2013-04-01

496

Oxidation induced softening in Al nanowires  

NASA Astrophysics Data System (ADS)

The mechanical properties of metallic nanowires depend dramatically on the atmospheric conditions. Molecular-dynamics simulations with ReaxFF were conducted to study tensile elastic deformation of oxidized Al nanowires. The thin amorphous oxide shell formed around Al nanowires had a very low Young's modulus of 26 GPa, due to its low density and low Al-O coordination. Consequently, for diameters less than 100 nm, the composite Young's modulus of oxide-covered Al nanowires showed a size dependence implying that in this case ``smaller is softer.'' The model developed also explained the discrepancies in the reported modulus values of nanometer-scale Al thin films.

Sen, Fatih G.; Qi, Yue; van Duin, Adri C. T.; Alpas, Ahmet T.

2013-02-01

497

A Thermodynamic Description of the Al-Cr-Si System  

Microsoft Academic Search

The Al-Cr-Si system was critically assessed using the CALPHAD technique. The solution phases (liquid, bcc, fcc, and diamond)\\u000a were described by a substitutional solution model. The compounds CrSi2, Cr3Si, AlCr2, ?Al8Cr5, ?Al8Cr5, Al4Cr, and Al11Cr2 in the Al-Cr-Si system were treated with sublattice models (Cr, Si)(Al, Cr, Si)2, (Cr, Si)3(Al, Cr, Si), (Al, Cr, Si)(Al, Cr)2, ?(Al, Cr, Si)8(Al, Cr,

Yu Liang; Cuiping Guo; Changrong Li; Zhenmin Du

2009-01-01

498

High-temperature tribological properties of CrAlN, CrAlSiN and AlCrSiN coatings  

Microsoft Academic Search

Cr–Al–Si–N coatings with high and low Cr\\/Al ratios (CrAlSiN and AlCrSiN, respectively) were deposited on WC substrates by cathodic arc and compared with a reference Cr–Al–N coating. The silicon content was close to 3at.%. X-ray diffraction analysis showed that CrAlN and CrAlSiN coatings exhibited the cubic Cr(Al)N structure, whereas in AlCrSiN a mixture of cubic Cr(Al)N and wurtzite-type AlN was

Tomas Polcar; Albano Cavaleiro

2011-01-01

499

Instandhaltungsmanagement als Gestaltungsfeld Ganzheitlicher Produktionssysteme  

NASA Astrophysics Data System (ADS)

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 als 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.

Dombrowski, Uwe; Schulze, Sven; Otano, Isabel Crespo

500

Reactive Plasma Spraying of Fine Al2O3/AlN Feedstock Powder  

NASA Astrophysics Data System (ADS)

Reactive plasma spraying (RPS) is a promising technology for in situ formation of aluminum nitride (AlN) coatings. Recently, AlN-based coatings were fabricated by RPS of alumina (Al2O3) powder in N2/H2 thermal plasma. This study investigated the feasibility of RPS of a fine Al2O3/AlN mixture and the influence of the plasma gases (N2, H2) on the nitriding conversion, and coating microstructure and properties. Thick AlN/Al2O3 coatings with high nitride content were successfully fabricated. The coatings consist of h-AlN, c-AlN, Al5O6N, ?-Al2O3, and a small amount of ?-Al2O3. Use of fine particles enhanced the nitriding conversion and the melting tendency by increasing the surface area. Furthermore, the AlN additive improved the AlN content in the coatings. Increasing the N2 gas flow rate improved the nitride content and complete crystal growth to the h-AlN phase, and enhanced the coating thickness. On the other hand, though the H2 gas is required for plasma nitriding of the Al2O3 particles, increasing its flow rate decreased the nitride content and the coating thickness. Remarkable influence of the plasma gases on the coating composition, microstructure, and properties was observed during RPS of the fine particles.

Shahien, Mohammed; Yamada, Motohiro; Yasui, Toshiaki; Fukumoto, Masahiro

2013-10-01