Role of Structural Heredity in Aging-Induced Microstructure and Transformation Behavior in Ni-rich Titanium Nickelide

摘要

The effect of different types of the initial structure of the Ti-50.7 at. Ni alloy obtained as a result of various processing (including cold drawing, severe plastic deformation, solution treatment at different temperatures) on specific features of aging-induced microstructure is studied. It was revealed that the peculiarities of the evolution of the martensitic transformation under aging strongly depend on both of above factors. A correlation between grain/subgrain size as well as the Ti3Ni4 precipitates and the temperature range of the reverse martensitic transformations was revealed. The narrowest range of the As(Rs)–Af reverse MT is realized in a material with a nanocrystalline structure formed as a result of aging of a predominantly amorphized structure obtained as a result of SPD. The widest range is typical for a coarse-grained recrystallized structure. The revealed regularities make it possible varying the temperature range of reverse martensitic transformations from 4 to 61 K.