Stability of phase boundary between L12-Ni3Al phases: A phase field study

Abstract

The evolution and stability of phase boundaries (PBs) between L12-Ni3Al phases in Ni75Al11V14 alloy aged at 1050k was studied using the microscopic equation phase-field method (MPFM). Four types of L12 PBs were found through atomic configuration, migration and occupation probability (OP). The evolution of metastable PBs and formation of stable PBs were tracked and explored, the effect of coherent elastic strain energy on the evolution and stability of PBs is also investigated by coupling the micro elastic theory with MPFM. In addition, the formation enthalpy, interface energy and electron distribution function of PBs are calculated by FP method, and the stability of PBs is further quantitatively predicted from the perspective of thermodynamic energy and gaining or losing electrons. FP calculation results are consistent with MPFM prediction, and the essence of the transition and stability of PBs is revealed based on the atomic migration dynamics, interface evolution morphology and thermodynamic energy. This is an effective method to further explore the formation and structure of PBs and design high stability PBs.