skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: First-principles study of crystal structure and stability of Al-Mg-Si-(Cu) precipitates

Abstract

Al-Mg-Si-(Cu) alloys form the basis of a wide variety of commercial precipitation-hardened alloys, and the observed precipitation sequence in these alloys is complex and involves a wide variety of metastable phases (e.g. GP zones, {beta}'', U1, U2, B{sup '}, {beta}{sup '}). Calculations of metastable phase equilibria in these alloys are virtually nonexistent due to the lack of quantitative information on the thermodynamics of the precipitate phases. We have undertaken an extensive, systematic first-principles study of energetics of all the reported precipitate phases of Al-Mg-Si-(Cu) alloys, using density functional-based calculations in both the local density and generalized gradient approximations. Our calculations help clarify the energetics of the metastable precipitate phases, and in certain cases, provide insight into the compositional changes of precipitates during aging. In addition to energetics, we also examine the relative volumes of the various phases, and discuss cases of significant deviation from that of the solid solution.

Authors:
;
Publication Date:
OSTI Identifier:
20634747
Resource Type:
Journal Article
Journal Name:
Acta Materialia
Additional Journal Information:
Journal Volume: 52; Journal Issue: 14; Other Information: DOI: 10.1016/j.actamat.2004.05.037; PII: S1359645404003106; Copyright (c) 2004 Elsevier Science B.V., Amsterdam, The Netherlands, All rights reserved; Country of input: International Atomic Energy Agency (IAEA); Journal ID: ISSN 1359-6454
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; ALUMINIUM ALLOYS; COPPER ALLOYS; CRYSTAL STRUCTURE; DENSITY FUNCTIONAL METHOD; FORMATION HEAT; MAGNESIUM ALLOYS; PRECIPITATION; SILICON ALLOYS; THERMODYNAMICS

Citation Formats

Ravi, C, and Wolverton, C. First-principles study of crystal structure and stability of Al-Mg-Si-(Cu) precipitates. United States: N. p., 2004. Web. doi:10.1016/j.actamat.2004.05.037.
Ravi, C, & Wolverton, C. First-principles study of crystal structure and stability of Al-Mg-Si-(Cu) precipitates. United States. https://doi.org/10.1016/j.actamat.2004.05.037
Ravi, C, and Wolverton, C. 2004. "First-principles study of crystal structure and stability of Al-Mg-Si-(Cu) precipitates". United States. https://doi.org/10.1016/j.actamat.2004.05.037.
@article{osti_20634747,
title = {First-principles study of crystal structure and stability of Al-Mg-Si-(Cu) precipitates},
author = {Ravi, C and Wolverton, C},
abstractNote = {Al-Mg-Si-(Cu) alloys form the basis of a wide variety of commercial precipitation-hardened alloys, and the observed precipitation sequence in these alloys is complex and involves a wide variety of metastable phases (e.g. GP zones, {beta}'', U1, U2, B{sup '}, {beta}{sup '}). Calculations of metastable phase equilibria in these alloys are virtually nonexistent due to the lack of quantitative information on the thermodynamics of the precipitate phases. We have undertaken an extensive, systematic first-principles study of energetics of all the reported precipitate phases of Al-Mg-Si-(Cu) alloys, using density functional-based calculations in both the local density and generalized gradient approximations. Our calculations help clarify the energetics of the metastable precipitate phases, and in certain cases, provide insight into the compositional changes of precipitates during aging. In addition to energetics, we also examine the relative volumes of the various phases, and discuss cases of significant deviation from that of the solid solution.},
doi = {10.1016/j.actamat.2004.05.037},
url = {https://www.osti.gov/biblio/20634747}, journal = {Acta Materialia},
issn = {1359-6454},
number = 14,
volume = 52,
place = {United States},
year = {Mon Aug 16 00:00:00 EDT 2004},
month = {Mon Aug 16 00:00:00 EDT 2004}
}