Effect of hot isostatic pressing followed by heat treatment on mechanical properties of additively manufactured Ti6Al4V alloy

Abstract

The growing application of additive manufacturing (AM) in aerospace, biomedical, and automotive industries has led to increased interest in optimizing the performance of Ti6Al4V alloy components fabricated by the Direct Metal Laser Sintering (DMLS) process. This study investigates the effect of Hot Isostatic Pressing (HIP) followed by post- processing heat treatments on the mechanical properties and microstructural evolution of additively manufactured Ti6Al4V alloy. Test specimens were fabricated via the DMLS technique and subjected to HIP at various temperatures 700°C, 910°C and 1060°C, followed by controlled heat treatments at different temperature. A comprehensive analysis was conducted to assess changes in density, hardness, tensile strength in multiple build orientations, wear resistance, and corrosion behavior. The results demonstrate that HIP significantly reduces internal porosity and promotes a more homogeneous microstructure, while subsequent heat treatment further enhances mechanical integrity. Tensile properties in x and y build directions (parallel to the build plane) showed higher tensile strength and ductility compared to the z direction and due to alteration in microstructure results in changes in the hardness of the material were observed, along with better tribological and corrosion performance in treated samples compared to their as-built sample. This study provides insights into optimizing post-processing protocols to enhance the structural performance of AM Ti6Al4V components.