Martensitic transformation behaviors of Ti-rich Ti–Ni alloy fibers fabricated by melt overflow

Abstract Ti 50 Ni 50 , Ti 50.5 Ni 49.5 , Ti 51 Ni 49 and Ti 51.5 Ni 48.5 fibers were fabricated by melt overflow process. The rapid solidification can increase the solubility above the equilibrium solubility. The effects of the rapid solidification of Ti-rich Ti–Ni alloys on the microstructure, transformation temperatures and shape memory characteristics are investigated. The addition of 0.5 at.% Ti in Ti 50 Ni 50 alloy greatly increases the transformation temperature. However, the transformation temperatures decrease again for Ti content exceeding 51 at.%. Results of thermal cycling tests under various constant stress levels reveal that the recoverable elongation associated with B2–B19 martensitic transformation of Ti 50.5 Ni 49.5 fibers is two times larger than that of Ti 51.5 Ni 48.5 alloy fiber.