Effect of aging temperature and time on the transformation behavior of a Ti-50.8 at.% Ni alloy with small grains

A Ti-50.8 at.% Ni alloy with small grains (average grain size of 1.8 μm) was subjected to various aging treatments. It is found that the frequently reported multi-stage martensitic transformation, i.e. the transformation including two B19’ martensite or two rhombohedral R-phase transformations, is absent in this study. The samples aged at 523–573 K show a single stage austenite↔Rphase transformation. A normal austenite→R-phase→martensite transformation is detected in the samples aged at 623–823 K.status: publishe