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Indexed by:期刊论文

Date of Publication:2019-02-15

Journal:COMPUTATIONAL MATERIALS SCIENCE

Included Journals:SCIE、Scopus

Volume:158

Page Number:359-368

ISSN No.:0927-0256

Key Words:Molecular dynamics; Atomistic simulation; Vacancy cluster; Stacking fault tetrahedra; Volumetric strain

Abstract:The transformation between voids and stacking fault tetrahedra (SFTs) under volumetric strain has been systematically investigated by atomistic computer simulation. It has been found out that equiaxial voids or SFTs have high stability under tensile or compressive strain. Molecular dynamic simulations show that the SFTs can transform to voids even at extremely low temperature under constant tensile strain. On the contrary, the equiaxial voids can transform to SFTs under constant compressive strain. The voids and SFTs can also transform to each other under cycling strain. During the transformation from SFTs to voids, four atoms at the vertex of SFT move outward first. Then, the {1 1 1} plane atoms move by layers toward one of the vertices. Finally, the opposing {1 1 1} plane atoms move toward the opposite direction, thereby forming planar voids. The planar voids transform to SFT through the opposite process. This strain-induced transformation is remarkably affected by temperature and strain rate. High temperature can advance the strain of the transformation, while the strain rate exerts opposite effects.