Combinatorial search for Ti-Ni-Hf high formable shape memory alloys

In this study, we searched for Ti-Ni-Hf high formable shape memory alloys (HFSMAs) using combinatorial methods. By adding Hf to Ti-Ni SMAs, the potential is that Ti-Ni SMAs become metallic glasses. For efficient material search, the glass transition temperature was evaluated through combinatorial measurement of electrical resistance during crystallization. From the results, we searched for Ti-Ni-Hf HFSMAs, which undergo glass transition in the amorphous state. Ni-rich Ti-Ni-Hf thin-film amorphous alloys with more than 10 at% Hf content became thin film metallic glasses, whereas Ni-poor samples did not. Further, we evaluated the effect of annealing temperature on the martensitic transformation temperature of Ti-Ni-Hf SMAs using combinatorial methods. From the results, we measured the reverse transformation start temperature A s at 368-404 K, and it varied with the annealing temperature and Hf composition.