Martensitic transformation behavior of Ti-Ni-Sn alloys

Abstract

Microstructural features and martensitic transformation behavior of Ti-Ni-Sn alloys were investigated by means of electron probe microanalysis (EPMA), X-ray diffraction (XRD) and differential scanning calorimetry (DSC). In a Ti-49.5Ni-0.5Sn alloy, Ti2Ni phase embedded in Ti-Ni matrix containing 0.7 at%Sn was observed. In a Ti-49.0Ni-1.0Sn alloy, Ti2Ni, unknown phase and Ti-Ni matrix containing 1.1 at%Sn were observed, while Ti2Ni and two different Ti-Ni matrices with 2.1 at%Sn and without Sn were observed in a Ti-50.0Ni-1.0Sn alloy. In a Ti-48.5Ni-1.5Sn alloy, Ti2Ni, Ti3Sn and Ti-Ni matrix containing Sri about 1.2 at% were observed. The B2-R-B19' transformation occurred in Ti-49.5Ni-0.5Sn, Ti-49.0Ni-1.0Sn and Ti-48.5Ni-1.5Sn alloys, while the B2-B19' transformation occurred in a Ti-50.0Ni-1.0Sn alloy. Substitution of Sn for Ni of an equiatomic TiNi alloy was effective to induce the R phase transformation. (C) 2012 Elsevier B.V. All rights reserved.