Study of the textural evolution in Ti-rich NiTi using synchrotron radiation

Abstract

The aim of the present work is to investigate the textural evolution in high-temperature phase (austenite – B2) of Ti-rich NiTi (Ni–51at%Ti) shape memory alloys (SMA). The alloy was subjected to different thermomechanical treatments involving various heat treatments and cold rollings (10% and 40%). The qualitative texture analysis was performed at BM20 (ROBL-CRG) of the European Synchrotron Research Facility (ESRF) using in-situ high-temperature X-ray diffraction (XRD) with a wavelength of 0.154nm. In-situ high-temperature texture determination has been carried out for the first time for Ni–Ti alloys, by annealing at different temperatures up to 800°C under a vacuum better than 10−4Pa. The discussion highlights the evolution of texture during annealing at high temperatures and the change in the coherency domain size and microstrain.