Effects of HIP Process Parameters on Microstructure and Mechanical Properties of Ti-6Al-4V Fabricated by SLM

Abstract

Ti-6Al-4V titanium alloy products formed by selective laser melting (SLM) are characterized by high strength and low plasticity. In addition, there may be pores inside the material, which may become a fracture sprouting point and accelerate the failure of the parts. Using an optical microscope (OM), scanning electron microscope (SEM), and electronic universal testing machine, the effects of hot isostatic pressing (HIP) parameters on the microstructure and tensile property of SLM-formed Ti-6Al-4V titanium alloy were investigated. The results show that HIP performed below the β-phase transition temperature, and the structure of the Ti-6Al-4V titanium alloy is composed of an α phase and β phase. With the increase in the HIP temperature, the α lath coarsens into a short rod, the content of the β phase increases and coarsens, and the tensile strength and yield strength of Ti-6Al-4V show a decreasing trend. With an HIP process performed at a temperature of 910 °C and pressure of 130 MPa for 2 h, the Ti-6Al-4V titanium alloy obtains the best matching of strength and plasticity.

Keywords

• Ti-6Al-4V
• selective laser melting
• hot isostatic pressing
• microstructure
• mechanical properties