Phase transformation behaviors of Ti-50.9 at.% Ni alloy after Equal Channel Angular Extrusion

Ti-50.9 at.% Ni alloy was subjected to Equal Channel Angular Extrusion (ECAE) at 723 K and 773 K. The initial coarse grains were refined after eight passes ECAE at 773 K, 0.2–0.3 μm as processed, the grains on longitudinal plane of samples were elongated along the shearing force direction of ECAE process. The R phase transformation of Ti-50.9 at.% Ni alloys was stimulated after ECAE processes, corresponding thermal peaks underwent within a larger temperature range, and the reverse R phase transformations of Ti-50.9 at.% Ni alloy after eight passes ECAE at 773 K, or four passes ECAE at 723 K, were eventually observed on heating. With the increase of extrusion passes, the martensitic transformation peak temperature (Mp) was lowered gradually.