Abstract
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′-Mg7Gd precipitate in Mg-Gd binary alloys were investigated using first-principles calculations based on density functional theory. The lattice mismatches between the coherent β′-Mg7Gd 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.
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Gao, L., Zhou, J., Sun, Z. et al. First-principles calculations of the β′-Mg7Gd precipitate in Mg-Gd binary alloys. Chin. Sci. Bull. 56, 1142–1146 (2011). https://doi.org/10.1007/s11434-010-4061-z
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DOI: https://doi.org/10.1007/s11434-010-4061-z