Structural evolution on thermal cycling in Ti-rich NiTi SMA

Shape-memory alloys (SMA) represent a class of metallic materials that has the capability of recovering a previously defined initial shape when subjected to an adequate thermomechanical treatment. Annealing of a Ti-rich Ni-Ti alloy has been followed by in situ high temperature diffraction in order to register the texture as well as the microstrain/microstress evolution. This type of study is relevant to the envisaged applications, because the type of preferential orientation and the corresponding anisotropic response of the material conditions contributes to the success of the SMA application. In the present study we have tested the feasibility of high temperature pole figures determination at ROBL (BM20) at the ESRF, and we have shown that there is a relation between the preferential orientation changing and the structural evolution taking place during annealing.