13 Matching Results

Search Results

Advanced search parameters have been applied.

in subjects: "Transition Element Compounds 360103* -- Metals & Alloys-- Mechanical Properties"

open access

First-principles investigation of mechanical behavior of B2 type aluminides: FeAl and NiAl

First-principles calculations of the elastic constants, shear fault energies, and cleavage strength of NiAl and FeAl are presented. For NiAl, we find that the dissociation of {l angle}111{r angle} superdislocation into partial dislocations is unlikely, due to a high antiphase boundary energy and a weak repulsive elastic force between partial dislocations. FeAl has a high ideal cleavage strength as a result of the directional d-bond formation at the Fe sites. The strong ordering behavior of NiAl… more

Date: January 1, 1990

Creator: Fu, C. L. & Yoo, M. H.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Bauschinger effects and work-hardening in spheroidized steels

The effects of cementite particles and subgrain boundaries on work-hardening behavior of spheroidized carbon steels were investigated by making direct measurements of residual internal stresses. These internal stresses developed due to plastic incompatibilities between elastic particles and an elastic-plastic matrix. A continuum analysis of these internal stress fields, based upon a multiple slip model, is presented and is found to be in good accord with the experiments. The internal stresses a… more

Date: May 1, 1977

Creator: Chang, Y W

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Rolling-contact and wear resistance of hard coatings on bearing-steel substrates

Ever-increasing needs for high-performance ball- and roller-bearing components that can endure extreme applications have led to a growing interest in hard coatings for improved fatigue life and wear resistance. In particular, hard TiN and TiC coatings and, quite recently, diamond like carbon films have attracted much attention from manufacturers that produce bearing systems for both rolling- and sliding-contact applications. This paper presents an overview that highlights recent incremental pro… more

Date: February 1, 1992

Creator: Erdemir, A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Tribological behavior of oil-lubricated, TiN-coated steel

The effects of titanium nitride (TiN) coatings on the tribological behavior of M50 and 52100 steels under both dry and synthetic polyol ester-based oil lubrication were evaluated using a reciprocating sliding pin-on-flat test machine. Under dry conditions, the TiN coating reduced the wear, which occurred by abrasion as well as the oxidation of the sliding surface. It also reduced the amount of wear-debris accumulation at the contact interface. During oil lubrication, wear and roughening of the … more

Date: February 1, 1992

Creator: Ajayi, O.O.; Erdemir, A.; Fenske, G.R.; Nichols, F.A. (Argonne National Lab., IL (United States)); Sproul, W.D.; Graham, M. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Atom-probe investigation of a micro-crack associated with hydrogen in a Fe-Ti alloy. [Fe-0. 29 wt % Ti]

We have for the first time witnessed the formation of a micro-crack and its development into a fracture using field ion microscopy. The crack initiated at a grain boundary intersection and propagated mainly, though not entirely, along the grain boundary. Compositional analysis at a hydrogen-produced micro-crack in a Fe-0.29 wt % Ti alloy by the high-performance time-of-fight atom-probe showed a large amount of hydrogen at the crack (H and H/sub 2/) and iron-hydrides (FeH, FeH/sub 2/). In contra… more

Date: January 1, 1980

Creator: Kuk, Y.; Sakurai, T. & Pickering, H.W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Superplasticity in a nickel silicide alloy: Microstructural and mechanical correlations

The superplastic properties of a nickel silicide based intermetallic alloy have been investigated as a function of strain, strain-rate, and temperature. The evolution of the microstructure during superplasticity, including grain growth, grain refinement, and cavitation, is reviewed. The relationship of the flow stress to strain and to strain-rate and the activation energy of the deformation process have been established. Finally, deformation mechanisms for superplasticity in the alloy at interm… more

Date: January 1, 1991

Creator: Stoner, S.L. (Lawrence Livermore National Lab., CA (United States)); Oliver, W.C. (Oak Ridge National Lab., TN (United States)) & Mukherjee, A.K. (California Univ., Davis, CA (United States). Dept. of Mechanical, Aeronautical and Materials Engineering)

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Nonmetallic inclusions in JBK-75 stainless steel

Stainless steel alloys that are chemically complex, such as A-286 or JBK-75, are designed to improve such high-temperature properties as strength. This is accomplished by precipitating secondary phases during aging. Such multicomponent systems, however, can also produce undesirable phases that are detrimental to forgeability and final mechanical properties. Cast segregation and numerous nonmetallic inclusions can have a degrading influence on the toughness and ductility of the alloy. Several di… more

Date: March 14, 1977

Creator: Brewer, A. W.; Krenzer, R. W.; Doyle, J. H. & Riefenberg, D. H.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Constant stress of XD trademark TiAl containing nitrogen

Ti-47at%Al+7vol%(TiN+TiB{sub 2}) alloys, produced by the Martin Marietta XD{trademark} process, were subjected to tensile constant stress creep deformation in the range 760--850{degree}C temperature and 138--276 MPa (20--40 ksi) stress. These alloys have a matrix of TiAl and Ti{sub 3}Al initially containing 1 to 10 {mu}m diameter equiaxed particles of TiB{sub 2} and Ti{sub 2}AlN. Microstructures were examined using optical, SEM and TEM methods in an attempt to correlate the substructures with t… more

Date: January 1, 1990

Creator: Robertson, E. & Martin, P. L.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Influence of radiation-induced segregation on ductility of a nickel-silicon alloy

Flat tensile specimens 60 ..mu..m thick of Ni-8 at. % Si were irradiated to bulk damage levels of 0.1 to 0.3 dpa with either 7 MeV protons or 28 MeV alpha particles at 750 K. The alpha bombarded specimens incurred 750 at. ppM He per 0.1 dpa in the course of their damage-generating irradiation. Radiation-induced silicon segregation gave rise to Ni/sub 3/Si layers at internal and external surfaces. Postirradiation tensile tests conducted either at 300 K or 720 K revealed fully ductile (chisel-edg… more

Date: January 1, 1986

Creator: Packan, N. H.; Schroeder, H. & Kesternich, W.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Structure and mechanical properties of Fe--Cr--Mo--C alloys with and without boron

Nonconventional heat treatments were designed to improve the mechanical properties of these martensitic steels. Results show that the as-quenched structures of both steels consist mainly of dislocated martensite. In the boron-free steel, there are more lath boundary retained austenite films. The boron-treated steel shows higher strengths at all tempering temperatures but with lower Charpy V-notch impact energies. Both steels show tempered martensite embrittlement when tempered at 350/sup 0/C fo… more

Date: May 1, 1976

Creator: Chen, Y. L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Novel concepts in weld metal science: Role of gradients and composite structure

The effects of compositional and microstructural gradients on weld metal properties are being investigated. Crack propagation is solidified alloy structures is being characterized as to solidification orientation and the profile of the compositional variations. The effects of compositional gradients, are considered based on a thermodynamic analysis, referred to as the Cahn-Hillard analysis, which describes the degree to which a local surface energy is modified by the presence of a compositional… more

Date: November 1991

Creator: Matlock, D.K. & Olson, D.L.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Effects of delta ferrite content on the mechanical properties of E308-16 stainless steel weld metal

The effects of ferrite content on the properties of type 308 stainless steel shielded metal-arc (SMA) welds were investigated. Welds were made at four levels of ferrite content ranging from 2 to 15 FN (Ferrite Number). Creep and tensile tests were performed. Specimens were aged at 1100/sup 0/C (593/sup 0/C) for times up to 10,000 h (36 Ms) and Charpy V-notch impact tests were performed. Chemical analysis of the original deposits, Magne-gage evaluations, and metallographic evaluation of tested s… more

Date: January 1, 1978

Creator: Edmonds, D. P.; Vandergriff, D. M. & Gray, R. J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

The effect of aging at 343 degrees C on type 308 stainless steel weldments

The effect of long-term aging at intermediate temperatures on the mechanical properties of stainless steel welds has been studied. Three type 308 multipass shielded metal-arc welds with ferrite levels of 4, 8, and 12% were aged up to 343{degrees}C. Tensile tests showed little effect of aging on either the yield or ultimate tensile strengths, but the impact toughness was significantly degraded. The extent of the degradation increased with increasing ferrite content and increasing aging time. Exa… more

Date: January 1, 1990

Creator: Alexander, D. J.; Alexander, K. B.; Miller, M. K. & Nanstad, R. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department