Crystallization and martensitic transformation behavior of Ti–Ni–Sn alloy ribbons

Crystallization behavior of rapidly solidified Ti–Ni–Sn alloys amorphous ribbons and martensitic transformation behavior after crystallization were examined by means of differential scanning calorimetry (DSC), X-ray diffraction (XRD) and transmission electron microscopy (TEM). Glass forming ability of Ti–Ni–Sn alloys increased with increasing Sn content and activation energy for crystallization increased from 151.2 ± 7.0 kJ/mol to 165.1 ± 9.0 kJ/mol with increasing Sn content from 5 at% to 7 at%, above which it almost kept constant. Crystallization occurs in the sequence of amorphous → (Ti,Sn)2Ni and B2 → B2 and Ti3Sn when Sn content is ≤5 at%, amorphous → (Ti,Sn)2Ni → B2 → B2 and Ti3Sn when Sn content is in the range of 5 at% and 10 at%, amorphous → (Ti,Sn)2Ni → Ti3Sn → B2 and Ti3Sn when Sn content is ≥10 at%. The crystallized Ti–Ni–Sn alloys showed the B2-R-B19′ martensitic transformation behavior. Rapid solidification was effective to separate the B2-R transformation from the R-B19′ transformation in Ti–Ni–Sn alloys.