Microstructure refinement induced by elastic compressive stress in Ti-6Al-4V alloy

The β→α transformation is a crucial and fundamental phase transformation in titanium and its alloys. This work investigated the effect of elastic compressive stress (ECS) on the microstructure and mechanical property during cooling from β phase region to α + β phase region in Ti-6Al-4V alloy. Results indicated that ECS in this process results in significant refinement and increased aspect ratios of α lamellae (α_L) and α colonies (α_C). These changes are attributed to the enhanced phase transformation driving force to promote nucleation of α lamellae. The ECS-cooling induced alloy exhibits higher hardness than the stress-free counterpart, mainly resulting from the refined microstructure. This work provides a potential method to tailor the microstructure and improve the mechanical properties of Ti alloys.