OCCUPANCY PROBABILITY OF a SUBLATTICE OF D022-NI3V IN NI-AL-V SYSTEM: DETERMINED BY MICROSCOPIC PHASE FIELD METHOD

alpha sublattice of D0(22)-N(i)3V is subdivided into alpha 1 and alpha 2 according to their coordination environment difference, which is different from the traditional view that alpha 1 and a2 are equals in crystallographic. We use a microscopic phase field method to study the occupancy probability (OP) of al and alpha 2, and conclude that: Antisite defects (V-alpha 1, V-alpha 2) and alloying elements (AlO2, Al-alpha 1) coexist in both al and alpha 2. The sequence of OP ranked in decreasing magnitude is Nial, Ni-alpha 2, V-alpha 2, Al-alpha 1, V-alpha 2, and AlO2 with a strong site preference of Ni, Al on alpha 1 while V on alpha 2. The inherent atom (Ni-alpha 1, Ni-alpha 2) have a negative correlation while the antisite defects (V-alpha 1, V-alpha 2) and alloying elements (Al, Alai) have a positive correlation to temperature, which involves the redistribution of Ni, Al and V atom, further, the phase transformation from D0(22) to L1(2).