The Impact of Aging Processes on Site Occupancy Probability of L12 and D022 Phase: Studied by Microelasticity Phase Field Model

摘要

The microelasticity phase field model is used to study the site occupancy probability (SOP) of L12-Ni3Al and D022-Ni3V phase which suffers the 1000K single temperature aging process (1000K STAP), 1000K and 1200K cyclic temperature aging process (CTAP), and 1200K single temperature aging process (1200K STAP), respectively. During the transformation of aging processes from 1000K STAP via CTAP to 1200K. STAP the SOP of inherent atom NiNi and AlAlin Ll2 phase together with NiNiand Vv in D022 phase decrease, but the antisite defect NiAl, Niv, Vni, and AlNi together with the substitutional defects AlNi, Alv, Val, and Vni increase. The SOP of NiNi in Ll2 is higher than NiNi in DO22, but AlAl is lower than Vv, additionally, the SOPs of antisite defect and substitutional defect of Ll2 are generally greater than that of DO22. The temporal evolution curves of CTAP are "great wall" like with the peek values are lower than the relevant higher calculated equilibrium values of the other two aging processes but trough values higher than the relevant lower ones.