Martensitic transformation behavior in Ti-Ni-X (Ag, In, Sn, Sb, Te, Tl, Pb, Bi) ternary alloys

Abstract

The microstructures and transformation behaviors of Ti-Ni-X (Ag, In, Sn, Sb, Te, TI, Pb, Bi) ternary alloys were investigated using electron probe micro-analysis (EPMA), X-ray diffraction (XRD), differential scanning calorimetry (DSC) and Micro Vickers hardness tests. All specimens consisted of Ti-Ni matrices and second phase particles. Ag, In and Sn were soluble in Ti-Ni matrices with a limited solubility (<= 1.0 at%), while Sb, Te, TI, Pb and Bi were not soluble. Two-stage B2-R-B19' transformation occurred in Ti-48.8Ni-1.2Ag, Ti-49.0Ni-1.0In and Ti-49.0Ni-1.0Sn alloys, while one-stage B2-1319' transformation occurred in Ti-49.0Ni-1.0Ag, Ti-49.0Ni-1.0Sb, Ti-49.0Ni-1.0Te, Ti-49.0Ni-1.0Pb and Ti-49.0Ni-1.0Bi alloys. Micro Vickers hardness of the alloys displaying the B2-R-B19' transformation (Hv 250-368) was much larger than that (<Hv 200) of the alloys displaying the B2-1319' transformation. Solid solution hardening was an important factor for inducing the B2-R transformation in Ti-Ni-X (X = non-transition elements) alloys. (C) 2013 Elsevier Ltd. All rights reserved.