Effect of plastic deformation on stress-induced martensitic transformation of nanocrystalline NiTi alloy

A nanocrystalline NiTi alloy with average grain size of 16 nm was acquired by cold drawing and annealing. The effect of plastic deformation on stress-induced martensitic transformation of the nanocrystalline NiTi alloy was investigated by the tension loading-unloading and heating-cooling cyclic tests. The results reveal that the nanocrystalline NiTi alloy experiences plastic deformation during the tensile loading process. The plastically deformed nanocrystalline NiTi alloy keeps the Lüders-type deformation, which is different from the coarse-grained and ultrafine-grained NiTi alloys.