Electron Irradiation Induced Multistage Martensitic Transformation in Ti-Rich Ti−Ni Alloy

This paper focuses on the microstructure and martensitic transformation of titanium−nickel (Ti−Ni) alloys under electron irradiation. There is no observable change of the microstructure after irradiation. Abnormal multistage martensitic transformations are observed in Ti-rich Ti-48 at % Ni alloys after electron irradiation. The three-stage reverse martensitic transformation can be achieved in the irradiated alloy, while unirradiated counterpart displays normal one-stage transformation during heating processes. The abnormal reverse martensitic transformation behavior caused by electron irradiation is due to the local stress field and the excessive defect concentration. The martensitic transformation behavior and temperature after annealing at 250 °C are consistent with the unirradiated counterpart. Additionally, the irradiated alloy exhibits superior thermal cycle stability to unirradiated samples.