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in creator/contributor: "Lesuer, D R"

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High Strain Rate-High Strain Response of an Ultrahigh Carbon Steel Containing 1.3% C and 3% SI

The mechanical response of a UHCS-1.3C material deformed at approximately 3000 s{sup -1} to large strains (60%) has been studied. The influence of three different heat treatments, which resulted in pearlitic, martensitic and tempered martensitic microstructures, on the stress-strain response has also been examined. Failure, at both the macroscopic and the microscopic levels, and the ability of the material to absorb energy in compression have been evaluated. Failure for all heat treatments occu… more

Date: February 19, 2003

Creator: Lesuer, D R; Syn, C K; Sherby, O M & Kum, D W

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Stress-Strain Rate Relations in Ultra High Carbon Steels Deformed in the Ferrite Range of Temperature

The stress-strain rate relations in ultrahigh carbon steels (UHCSs) have been analyzed at high temperatures in the ferrite range where dislocation slip is the principal deformation mechanism. Specifically, the present investigation centers on the factors influencing the strength of UHCS in the ferrite range of 500 to 700 C and in the strain rate range of 10{sup -3} to 10{sup 3} s{sup -1}. These steels contain iron carbide as a second phase either in the form of spheroidite or pearlite and vary … more

Date: February 20, 2003

Creator: Syn, C K; Lesuer, D R; Sherby, O D & Taleff, E M

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Creep fracture during solute-drag creep and superplastic deformation

Creep fracture behavior has been studied in Al-Mg and Al-Mg-Mn alloys undergoing solute-drag creep and in microduplex stainless steel undergoing both solute-drag creep and superplastic deformation. Failure in these materials is found to be controlled by two mechanisms, neck formation and cavitation. The mechanism of creep fracture during solute-drag creep in Al-Mg is found to change from necking-controlled fracture to cavitation-controlled fracture as Mn content is increased. Binary Al-Mg mater… more

Date: October 1, 1996

Creator: Taleff, E. M.; Lesuer, D. R.; Syn, C. K. & Henshall, G. A.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Superplastic deformation in two microduplex stainless steels

The deformation behavior and mechanisms of superplastic flow in two microduplex stainless steels (SuperDux64 and Nitronic 19D) were studied at {similar_to}0.7T{sub m}. The two steels differed in initial grain size by a factor of 3. Both steels exhibited solute-drag-controlled grain boundary sliding in a high temperature {gamma}+{delta} phase field. In a lower temperature {gamma}+{sigma} phase field, the fine-grained steel ({bar L}=5{mu}m) exhibited climb-controlled grain boundary sliding and th… more

Date: September 1, 1996

Creator: Lesuer, D. R.; Nieh, T. G.; Syn, C. K. & Taleff, E. M.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanical behavior of ultrahigh strength ultrahigh carbon steel wire and rod

Ultrahigh-carbon steels (UHCSS) can achieve very high strengths in wire or rod form. These high strengths result from the mechanical work introduced during wire and rod processing. These strengths have been observed to increase with carbon content. In wire form, tensile strengths approaching 6000 MPa are predicted for UHCS containing 1. 8%C. In this paper, we will discuss the influence of processing (including rapid transformation during wire patenting) and micros ct- ure on the mechanical beha… more

Date: July 22, 1997

Creator: Lesuer, D. R.; Syn, C. K.; Sberby, O. D. & Whittenherger, W. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Processing and mechanical behavior of hypereutectoid steel wires

Hypereutectoid steels have the potential for dramatically increasing the strength of wire used in tire cord and in other high strength wire applications. The basis for this possible breakthrough is the elimination of a brittle proeutectoid network that can form along grain boundaries if appropriate processing procedures and alloy additions are used. A review is made of work done by Japanese and other researchers on eutectoid and mildly hypereutectoid wires. A linear extrapolation of the tensile… more

Date: June 25, 1996

Creator: Lesuer, D. R.; Syn, C. K.; Sherby, O. D. & Kim, D. K.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An Analysis of Gas Pressure Forming of Superplastic AL 5083 Alloy

Al 5083 disks of a superplastic forming grade were gas-pressure formed to hemispheres and cones at constant forming pressures with and without back pressure. The forming operation was performed using an in-house designed and built biaxial forming apparatus. The temporal change of dome heights of the hemispheres and cones were measured for the different forming and back pressures applied. The flow stresses and strain rates developed at the top of the dome during the forming step were shown to cl… more

Date: May 4, 2001

Creator: Syn, C K; O'Brien, M J; Lesuer, D R & Sherby, O D

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

An Evaluation of Power Law Breakdown in Metals, Alloys, Dispersion Hardened Materials and Compounds

Creep at high stresses often produces strain rates that exceed those that would be predicted by a power law relationship. In this paper, we examine available high stress creep data for pure metals, solid solution alloys, dispersion strengthened powder metallurgy materials and compounds for power law breakdown (PLB). The results show that, if PLB is observed, then the onset of PLB is generally observed at about {epsilon}/D{sub eff} = 10{sup 13} m{sup -2}, where D{sub eff} is the effective diffus… more

Date: October 20, 1999

Creator: Lesuer, D. R.; Syn, C. K. & Sherby, O. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanical and Thermal Properties of Ultra-High Carbon Steel Containing Aluminum

The properties of ultrahigh carbon steels (UHCS) are strongly influenced by aluminum additions. Hardness studies of quenched UHCS-Al alloys reveal that the temperature for the start of transformation increases with increases in aluminum content. It is shown that this change is a function of the atomic percent of solute and of the valence state when comparisons are made with UHCSs containing silicon and tin as solutes. The thermal expansion of UHCSs with dilute aluminum additions shows no discon… more

Date: October 3, 2005

Creator: Syn, C. K.; Lesuer, D. R.; Goldberg, A.; Tsai, H. C. & Sherby, O. D.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Mechanism of Ultrafine Grain Formation During Intense Plastic Straining in an Aluminum Alloy at Intermediate Temperatures

The mechanism of grain formation during equal channel angular extrusion (ECAE) in a 2219 Al alloy has been studied at intermediate and high temperatures. It was shown that continuous dynamic recrystallization (CDRX) occurred during intense plastic straining and resulted in the formation of submicrometer grains at temperatures ranging from 250 C to 300 C. Higher temperatures (< 300 C) hindered CDRX. This is caused by the fact that nucleation controls CDRX in the aluminum alloy. Dislocation re… more

Date: September 21, 2000

Creator: Kaibyshev, R.; Sitdikov, O.; Mazurina, I. & Lesuer, D. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Enhanced tensile ductility in Al-Mg alloys by solid-solution interactions

The development of methods for obtaining high tensile elongation in aluminum alloys is of great importance for the practical forming of near-net-shape parts. Current superplastic alloys are limited in use by high material costs. The utilization of solute-drag creep processes, the approach used in this study, to obtain enhanced tensile ductility in aluminum alloys has lead to tensile elongations of up to 325% in simple, binary Al-Mg alloys with coarse grain sizes. This method has the advantage o… more

Date: November 29, 1995

Creator: Taleff, E. M.; Henshall, G. A.; Lesuer, D. R.; Nieh, T. G. & Wadsworth, J.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Enhanced tensile ductility of coarse-grain Al-Mg alloys

The effective forming of near-net-shape parts from aluminum alloys is of significant interest for automotive and aerospace applications. It has traditionally been thought that the very high tensile ductilities necessary for many near-net-shape forming operations, in excess of 100%, were only available in fine-grain superplastic materials. Tensile ductilities in excess of 300%, however, have been attained in coarse-grain, non-superplastic, binary Al-Mg alloys as a result of a solute-drag-control… more

Date: December 20, 1995

Creator: Taleff, E. M.; Henshall, G. A.; Lesuer, D. R.; Nieh, T. G. & Wadsworth, J.

Item Type: Report

Partner: UNT Libraries Government Documents Department

open access

Laminated metal composites of ultrahigh carbon steel/brass and Al/Al-SiC: Processing and properties

We have fabricated laminated metal composites of (i) ultrahigh carbon steel (1.8%C) and brass (70Cu-30Zn), and (ii) aluminum 5182 and aluminum 6061 with 25 vol.% SiC{sub p}. The laminates were prepared by hot pressing alternating layers of the component materials in an argon gas atmosphere. The steel was thermo-mechanically processed to produce a fine grained microstructure that exhibited superplasticity. The brass and aluminum materials were obtained from commercial sources and used in the as-… more

Date: October 1, 1991

Creator: Syn, C. K.; Lesuer, D. R.; Cadwell, K. L.; Sherby, O. D. & Brown, K. R.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Fracture behavior of laminated discontinuously reinforced aluminum material

Laminated metallic composites are being developed for applications which require high specific stiffness and fracture resistance. Recent work with laminated discontinuously reinforced aluminum (DRA) materials has demonstrated the potential for marked improvements in stable crack growth resistance via extrinsic toughening. The purpose of this work is to compare the fracture mechanisms and fracture resistance of laminated DRA materials to unlaminated DRA materials. In particular, the production o… more

Date: May 1, 1994

Creator: Osman, T. M.; Lewandowski, J. J.; Lesuer, D. R.; Syn, C. K. & Hunt, W. H. Jr

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On the Development of MMCS Containing Copper with Silicon Carbide Reinforcement using Nanomaterials and Dynamic Compaction

Metal matrix composites (MMCs) are promising engineering materials for a wide spectrum of applications. There are many possible matrix-reinforcement combinations including MMCs containing copper or copper alloy matrices [1-3]. The present study is concerned with copper reinforced with SiC particles. The materials studied here were processed from nano-scale matrix powders and consolidated using dynamic compaction.

Date: April 10, 2002

Creator: Popov, V A; Lesuer, D R; Kotov, I A; Ivanov, V V; Smirnov, O M; Marmulev, A V et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

Roll forming technology for manufacturing axisymmetric automotive components

A unique roll forming technology that permits complex axisymmetric components, such as automobile wheels and turbine disks, to be formed in a single forming operation, has been developed by two Russian Institute, the Institute of Technical Physics of the Russian Federal Nuclear Center and the Institute for Metals Superplasticity Problems. This process was used to fabricate automobile wheels from a Russian AVT alloy, a 6010 aluminum alloy equivalent. The process included steps of isothermal roll… more

Date: October 28, 1997

Creator: Syn, C. K.; Lesuer, D. R.; Bieh, T. G.; Yang, H. S.; Brown, K. R.; Kaibyshev, R. O. et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department

open access

On the Development of Microstructure in a Metal Matrix Composite Using Nano-Materials

Metal matrix composites (MMCs) containing matrices with nanometer grain sizes have been produced from pure aluminum nano-powders (particle sizes 50-200 nm) with SiC reinforcement (particle sizes 3-10 {micro}m). The pure Al nano-powders were produced using an exploding wire technique. Dynamic loading using a magnetic impulse technique has been used to compact the MMC to high density. The dynamic compaction process results in excellent wetting of the SiC particles by the nanocrystalline Al powder… more

Date: September 10, 2001

Creator: Popov, V A; Lesuer, D R; Kotov, I A; Ivanov, V V; Aksenov, A A; Khodos, I I et al.

Item Type: Article

Partner: UNT Libraries Government Documents Department