Tensile and fatigue properties of additively manufactured titanium alloy: Effects of heat treatment and surface processing

Titanium alloy has been regarded as one of the most demandable and potential materials in the additive manufacturing (AM) community due to its good printability and extensive applications. While the durability and ductility of the as-built titanium alloy specimens were markedly lower than the forgings due to the rough surfaces, acicular martensite structure and high stress state. Here, heat treatment and surface treatment (i.e., shot blasting and machining) were performed on the laser powder bed fused (LPBF) Ti-6Al-4V specimens and forging counterparts to investigate the effects of surface roughness and microstructure on the tensile and fatigue properties. The results indicated that the tensile and fatigue strength were greatly improved after surface treatment, and fatigue limits was further improved after heat treatment. The optimized combination of heat treatment and surface processing provides reliable strategy guidance for the mechanical property improvement of LPBF-produced Ti-6Al-4V alloy.