Influence of texture and transformation strain on the superelastic performance of a new Ti–20Zr–3Mo–3Sn alloy

Abstract In this work, the superelastic behavior of a new metastable β Ti–20Zr–3Mo–3Sn (at.%) biomedical alloy displaying stress-induced α" martensitic transformation (SIM) was investigated by cyclic tensile tests, electron back-scattered diffraction (EBSD) and in situ synchrotron X-ray diffraction (SXRD) for 3 different solution treatment temperatures: 700 °C, 800 °C and 900 °C. The EBSD observations revealed that the Ti–20Zr–3Mo–3Sn alloy showed a strong dependence of the solution treatment temperatures on crystallographic texture. SXRD diffraction profiles acquired under cyclic loading/unloading tensile tests clearly illustrated the reversible SIM α" transformation. In addition, the lattice parameters of β and SIM α" phases were measured for each cycle in order to establish the evolution of lattice parameters during the deformation and to calculate the maximum transformation strain for any crystallographic direction. A high recovery strain of 3.5% was obtained by tensile test after a solution treatment at 700 °C for 30 min. This high recovery strain is due to the fact that the maximum transformation strain is obtained along the tensile direction displaying the favorable β {100} β recrystallization texture. The performance of the Ti–20Zr–3Mo–3Sn alloy is discussed and compared with other superelastic alloys such as NiTi and (Ti–Nb)-based alloys.