Grain refinement of a rapidly solidified Ti–30Ni–20Cu alloy by two-step annealing

Ti–30Ni–20Cu (at.%) alloy ribbons with an average grain size of 0.25–0.28 μm were obtained by applying two-step annealing, comprising a first annealing step at 773–823 K and a second annealing step at 748 K, to amorphous melt-spun ribbons, which was very small compared with ribbons obtained by one-step annealing at 748–823 K (0.64–1.20 μm). Hysteresis and elongation associated with the B2–B19 transformation were decreased by two-step annealing, while the fracture stress and strain increased.