Effect of hot isostatic pressing on the microstructure and mechanical properties of porous Ti-6Al-4V alloy manufactured by laser powder bed fusion

Laser powder bed fusion (LPBF) enables the production of Ti-6Al-4V alloys with tailored porous structures, which are beneficial for biomedical applications due to their reduced elastic modulus and enhanced bone integration potential. This study examines the effect of hot isostatic pressing (HIP) on the microstructure and mechanical properties of diamond and gyroid porous structures fabricated by LPBF. Solid tensile specimens served as reference materials. HIP significantly reduced porosity, decreased ultimate tensile strength and hardness, but markedly increased ductility (from 6% to 17%). Compressive strengths reached approximately 100 MPa (diamond) and 240 MPa (gyroid), with HIP causing only a slight increase in strain. However, HIP notably improved bending performance, raising the flexural strength of gyroid structures from 280 MPa (as-printed) to 340 MPa (post-HIP). The strength of LPBF-fabricated Ti-6Al-4V porous structures is reduced by HIP, but their ductility and bending performance are enhanced, making them more suitable for biomedical applications.