| Abstract Scope |
In this paper, α sublattice of D0<sub>22</sub>-Ni<sub>3</sub>V is subdivided into α1 and α2 according to the location they reside. We use an atomic-scale microscopic phase field to study the occupancy probabilities (OP) of α1 and α2, including antisite defect, substitutional defect and phase transition. The results are as follows: Antisite defect (V<sub>α1</sub>, V<sub>α2</sub>) and substitutional defect (Al<sub>α1</sub>, Al<sub>α2</sub>) coexist in both α1 and α2, and the sequence of OP ranked in magnitude is Ni<sub>α1</sub>, Ni<sub>α2</sub>, V<sub>α2</sub>, Al<sub>α2</sub>, V<sub>α1</sub>, and Al<sub>α1</sub>. The inherent atom (Ni<sub>α1</sub>, Ni<sub>α2</sub>) decline but defects rise with the elevated temperature. At temperature lower than 1150K, part of the being substituted Ni exchanges V on β sublattice and the other dissolves into matrix or enters L12 structure, while at temperature higher than 1150K the being substituted Ni together with Ni from matrix enters β sublattice, which accounts for the complicated phase transition from D0<sub>22</sub> to L1<sub>2</sub>. |