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Title: The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation

Abstract

The plastic anisotropy resulting from the initial deformation microstructure and various aging treatments applied to several regions of an AA2090 near-net-shape extrusion has been investigated. Yield behavior was measured by uniaxial compression in multiple orientations of each region. Two models of the plastic anisotropy were generated: the Taylor/Bishop-Hill model, based on crystallographic texture, and the plastic inclusion model, developed by Hosford and Zeisloft, which incorporates anisotropic-precipitate effects. In overaged conditions, the Taylor/Bishop-Hill model adequately describes the observed plastic anisotropy. As the strengthening increment due to second-phase particles increases, there is a concurrent increase in the magnitude of the precipitate contribution to anisotropy. This anisotropy can not be accurately predicted solely by crystallographic texture. By incorporation of terms describing the precipitate anisotropy, the plastic inclusion model correctly predicts the yield strength variation in all regions tested. Examination of the fundamental interaction between matrix and precipitation strengthening reveals that there is a stronger basis for taking the critical resolved shear stress (CRSS) of the precipitates as a constant, rather than their effective yield strength. This consideration provides a more consistent and accurate form of the plastic inclusion model.

Authors:
;  [1]
  1. Univ. of Virginia, Charlottesville, VA (United States). Dept. of Materials Science and Engineering
Publication Date:
Sponsoring Org.:
National Aeronautics and Space Administration, Washington, DC (United States)
OSTI Identifier:
413283
Resource Type:
Journal Article
Journal Name:
Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science
Additional Journal Information:
Journal Volume: 27; Journal Issue: 11; Other Information: PBD: Nov 1996
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM BASE ALLOYS; DEFORMATION; MICROSTRUCTURE; LITHIUM ALLOYS; COPPER ALLOYS; ZIRCONIUM ADDITIONS; PLASTICITY; MATHEMATICAL MODELS; TEXTURE; PRECIPITATION; AGING; YIELD STRENGTH; PREDICTION EQUATIONS

Citation Formats

Lyttle, M T, and Wert, J A. The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation. United States: N. p., 1996. Web. doi:10.1007/BF02595442.
Lyttle, M T, & Wert, J A. The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation. United States. doi:10.1007/BF02595442.
Lyttle, M T, and Wert, J A. Fri . "The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation". United States. doi:10.1007/BF02595442.
@article{osti_413283,
title = {The plastic anisotropy of an Al-Li-Cu-Zr alloy extrusion in unidirectional deformation},
author = {Lyttle, M T and Wert, J A},
abstractNote = {The plastic anisotropy resulting from the initial deformation microstructure and various aging treatments applied to several regions of an AA2090 near-net-shape extrusion has been investigated. Yield behavior was measured by uniaxial compression in multiple orientations of each region. Two models of the plastic anisotropy were generated: the Taylor/Bishop-Hill model, based on crystallographic texture, and the plastic inclusion model, developed by Hosford and Zeisloft, which incorporates anisotropic-precipitate effects. In overaged conditions, the Taylor/Bishop-Hill model adequately describes the observed plastic anisotropy. As the strengthening increment due to second-phase particles increases, there is a concurrent increase in the magnitude of the precipitate contribution to anisotropy. This anisotropy can not be accurately predicted solely by crystallographic texture. By incorporation of terms describing the precipitate anisotropy, the plastic inclusion model correctly predicts the yield strength variation in all regions tested. Examination of the fundamental interaction between matrix and precipitation strengthening reveals that there is a stronger basis for taking the critical resolved shear stress (CRSS) of the precipitates as a constant, rather than their effective yield strength. This consideration provides a more consistent and accurate form of the plastic inclusion model.},
doi = {10.1007/BF02595442},
journal = {Metallurgical and Materials Transactions. A, Physical Metallurgy and Materials Science},
number = 11,
volume = 27,
place = {United States},
year = {1996},
month = {11}
}