Atomistic simulation of the point defects in TaW ordered alloy

• Published in: Pramāṇa 2011, Vol.76 (1), p.127-138
• Main Authors: LIN, ZHONG-LIANG, ZHANG, JIAN-MIN, ZHANG, YAN, JI, VINCENT
• Format: Article
• Language: English
• Subjects: Astronomy; Astrophysics and Astroparticles; Observations and Techniques; Physics; Physics and Astronomy
• ISSN: 0304-4289; 0973-7111
• DOI: 10.1007/s12043-011-0005-7

. Combining molecular dynamics (MD) simulation with modified analytic embedded-atom method (MAEAM), the formation, migration and activation energies of the point defects for six-kind migration mechanisms in B 2 -type TaW alloy have been investigated. The results showed that the anti-site defects Ta W and W Ta were easier to form than Ta and W vacancies owing to their lower formation energies. Comparing the migration and activation energies needed for six-kind migration mechanisms of a Ta (or W) vacancy, we found that one nearest-neighbour jump (1NNJ) was the most favourable because of its lowest migration and activation energies, but it would lead to a disorder in the alloy. One next-nearest-neighbour jump (1NNNJ) and one third-nearest-neighbour jump (1TNNJ) could maintain the ordered property of the alloy but required higher migration and activation energies. So the 1NNNJ and 1TNNJ should be replaced by straight [100] six nearest-neighbor cyclic jumps (S[100]6NNCJ) (especially) or bent [100] six nearest-neighbour cyclic jumps (B[100]6NNCJ) and [110] six nearest-neighbor cyclic jumps ([110]6NNCJ), respectively.