Structural and Textural Evolution during Cold Work in Ti-Rich Ni-Ti Shape Memory Alloy

The properties and cost have made the Nickel-Titanium (NiTi) shape memory alloys (SMA) attractive for a variety of applications wherein shape memory effect (SME) / superelasticity (SE) and biocompatibility are important. Anisotropy of the shape recovery associated with shape memory effect strongly depends on the type of preferential orientation, that is present, as well as the ‘strength’ of the texture. The goal of the present work is to investigate the structural and textural evolution in annealed (at 500°C for 30 minutes in air) Ti-Rich Ni-Ti SMA (Ni51at%Ti) when subjected to cold rolling at 8 distinct thickness reduction (2, 4, 6, 8, 10, 20, 30 and 40%). The textural results were obtained by X-Ray Diffraction (XRD) at room temperature (B19’ phase). The structural evolution was observed by temperature dependent XRD spectra. Indentation hardness test at room temperature (B19’) was also performed. Differential Scanning Calorimetry (DSC) was used to identify the transformation temperatures and the phase stabilization after all steps of cold work treatments