Effect of hot isostatic pressing on the mechanical and corrosive properties of Ti–Ni alloy fabricated by selective laser melting

Abstract

Hot isostatic pressing (HIP) is capable of mitigating the internal defects of materials, such as pores and cracks, resulting in improved mechanical properties and corrosion resistance, so it is particularly suitable as a post-treatment technology for the Ti–Ni alloys fabricated by selective laser melting (SLM), which display a broad application prospect in the biomedical field. Herein, the effect of HIP treatment on the mechanical and corrosion-resistant properties of SLM Ti–Ni alloys was systematically investigated. It was demonstrated that HIP treatment did not substantially affect the phase transformation behavior of the SLM Ti–Ni alloy, only showing a slight decrease in the values of As and Ms. However, HIP treatment improved the ultimate tensile strength and the elongation to fracture of the SLM Ti–Ni alloy by 67.3% and 23.2%, respectively. Meanwhile, the corrosion current density was reduced by two orders of magnitude after HIP treatment, indicating the significantly increased corrosion resistance. The enhanced mechanical properties and corrosion resistance of SLM Ti–Ni alloy were credited with the elevated temperature and pressure applied during the HIP process, which significantly eliminated the porosity defects and made the microstructure more uniform. These findings highlight the importance of performing HIP to enhance the comprehensive properties of SLM Ti–Ni alloys, which can expand the application prospects of SLM Ti–Ni alloys in the biomedical field.