Interfacial instability-driven amorphization/nanocrystallization in a bulk Ni45Cu5Ti33Zr16Si1 alloy during solidification

Abstract

We report on experimental evidence for local amorphization∕nanocrystallization at the interfaces between the B2-ordered Ni(Ti,Zr) phase and the NiTiZr phase with P63∕mmc during solidification of a multicomponent Ni45Cu5Ti33Zr16Si1 alloy. So far there are several well-known mechanisms for interfacial amorphization in the solid state but no interfacial instability-driven amorphization∕nanocrystallization during transition from liquid to solid state has been reported to our knowledge. The curvature of the interfacial area of the ordered Ni(Ti,Zr) phase is locally negative accompanying reverse atomic diffusion. This results in the frustration of the strong ordering tendency of the Ni(Ti,Zr) phase, and induces local amorphization∕nanocrystallization.