Influence of 18 MeV proton irradiation on the R-phase transformationof a TiNi shape memory alloy

Ti-50.6at.%Ni shape memory alloy specimens were irradiated under the austenite state (parent phase) using a tandem accelerator by 18MeV protons with doses of 1.53×1013and 1.53×1014H+/cm2. The microstructure and phase transformation of the specimens before and after irradiation were examined by transmission electron microscopy (TEM) and differential scanning calorimetry (DSC). After the irradiation the parent phase (austenite) was stabilized. R-phase transformation start temperature and the reverse martensitic transformation finish temperature decreased with the increasing proton fluence. They decreased about 13K and 6K at a dose of 1.53×1014H+/cm2, respectively. The reverse martensitic transformation start temperature and Rphase transformation finish temperature were not affected by t