Effects of proton irradiation on transformation behavior of TiNi shape memory alloy thin films

In this work, Ti-49.8 at.% Ni shape memory alloy (SMA) thin films were irradiated by 60-keV protons with two types of doses: 5×1016 and 1×1017 H+/cm2. The influence of proton irradiation on the transformation behavior of TiNi shape memory alloy films was investigated by differential scanning calorimetry (DSC) and glancing-incidence X-ray diffraction (GIXRD). The martensite transformation temperatures and austenite transformation temperatures shifted to lower value after proton irradiation, whereas proton irradiation has little effect on the R-phase transformation temperatures. This observation can be attributed to the formation of hydrides after proton irradiation.