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

Abstract

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)(2)Ni and B2 -> B2 and Ti3Sn when Sn content is <= 5 at%, amorphous -> (Ti,Sn)(2)Ni -> B2 -> B2 and Ti3Sn when Sn content is in the range of 5 at% and 10 at%, amorphous -> (Ti,Sn)(2)Ni -> 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. (C) 2012 Elsevier Ltd. All rights reserved.