Study on Phase Transformation and Electrochemical Corrosion of TiNi Alloy Formed by Laser Solid Forming

TiNi shape memory alloy (SMA) prepared by laser solid forming (LSF) has wide application prospect and research value. In this work, LSF-Ti49.2Ni50.8 alloy was tested by X-ray diffraction (XRD), differential scanning calorimetry (DSC), and transmission electron microscopy (TEM). The microscopic characterization results show that there is a small amount of martensitic slat in TiNi alloy besides the TiNi substrate. Lenticular R phase is densely distributed around the martensitic slat. B2→R and R→M phase transitions occur in the alloy due to the high cooling rate during laser solid forming. The results of methyl thiazolyl tetrazolium (MTT) assay and electrochemical corrosion test show that the alloy has good biocompatibility and excellent corrosion resistance and has the potential to be used as a biomedical material.