First-principles calculations of theβ-Mg7Gd precipitate in Mg-Gd binary alloys

The metastable β phase is often the most effective hardening precipitate in Mg-Gd based alloys. In this paper, the structural, elastic and electronic properties of the recently identified β-MgTGd precipitate in Mg-Gd binary alloys were investigated using first-principles calculations based on densit...

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Bibliographic Details
Published in:Chinese science bulletin 2011-04, Vol.56 (11), p.1142-1146
Main Authors: Gao, Lei, Zhou, Jian, Sun, ZhiMei, Chen, RongShi, Han, EnHou
Format: Article
Language:English
Subjects:
Chemistry/Food Science
Earth Sciences
Engineering
Humanities and Social Sciences
Life Sciences
multidisciplinary
Physics
Science
Science (multidisciplinary)
二元合金
密度泛函理论
弹性模量
机械性能
第一原理计算
金沉淀
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Summary:The metastable β phase is often the most effective hardening precipitate in Mg-Gd based alloys. In this paper, the structural, elastic and electronic properties of the recently identified β-MgTGd precipitate in Mg-Gd binary alloys were investigated using first-principles calculations based on density functional theory. The lattice mismatches between the coherent [Y-MgvGd precipitate and α-Mg matrix are discussed and used to rationalize the experimentally observed morphology of the precipitate. The mechanical properties were investigated through analysis of the single-crystal elastic constants and the polycrystalline elastic moduli. It is found that β′-Mg7Gd is brittle in nature. Strong covalent bonding in β′-Mg7Gd, as inferred from its electronic structure, further explains its mechanical properties. Our theoretical results show good agreement with experimental measurements.
ISSN:1001-6538
1861-9541
DOI:10.1007/s11434-010-4061-z