Microscopic Phase-Field Study on the Compositions of Ordered Domain Interfaces Formed between L12 Phases in Ni75AlxV25-x Alloys

Abstract:

Microscopic phase-field model was used to study the effect of atomic structure of interfaces, composition of alloys and elastic strain energy on the compositions of ordered domain interfaces formed between L12-Ni3Al phases in Ni75AlxV25-x alloys. The results demonstrate that the depletion degree of Ni is the lowest, and the depletion degree of Al and the segregation degree of V are the highest at the interface (100)//(200)·?[001]; the depletion degree of Ni is the highest, and the depletion degree of Al and the segregation degree of V are the lowest at the interface (200)//(200) among the three kinds of interfaces formed between L12-Ni3Al phases. With the Al concentration of alloys increasing, the concentration of Al increases while the concentrations of Ni and V decrease at the ordered domain boundaries formed between L12-Ni3Al phases. When the elastic strain energy is considered during the simulation, the concentrations of Ni and Al increase while the concentration of V decrease at the three kinds of ordered domain interfaces. The effect of elastic strain energy on the composition of (200)//(200)·?[001] and (100)//(200)·?[001] is much more remarkable than on that of (200)//(200).