Stability of vacancy-type defect clusters in Ni based on first- principles and molecular dynamics simulations

SJ Zhao and YW Zhang and WJ Weber, SCRIPTA MATERIALIA, 145, 71-75 (2018).

DOI: 10.1016/j.scriptamat.2017.10.003

Using first-principles calculations based on density-functional theory, the energetics of different vacancy-type defects, including voids, stacking fault tetrahedra (SFT) and vacancy loops, in Ni are investigated, It is found that voids are more stable than SET at 0 K, which is also the case after taking into account the volumetric strains. By carrying out ab initio molecular dynamics simulations at temperatures up to 1000 K, direct transformations from vacancy loops and voids into SFT are observed. Our results suggest the importance of temperature effects in determining thermodynamic stability of vacancy dusters in face-centered cubic metals. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.

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