Quantitative analysis of the effect of α-phase on mechanical property of Ti-6Al-4V alloy during hot working process

In this paper, the morphologic evolution of α-phases and their influence on mechanical properties during the hot working process of the Ti-6Al-4V alloy has been quantitatively investigated. Samples with a variety of different features of α-phase were obtained by hot working. A quantitative analysis of SEM/OM images is carried out to determine the features of α-phase before and after deformation, including the length, thickness, aspect ratio and volume fraction of α-phase. It was found that the α-phase platelet thickness increases with the increasing of forging height reduction on subsequent solution and aging treatment, larger height reduction would reduce the aspect ratio and length of α-phase and further makes the α-phase closest to equiaxed morphology. Moreover, the influence of the α-phase features on the mechanical properties was systematically investigated. The results indicate that the mechanical properties are strongly determined by the features of the α-phase, especially the thickness and volume fraction of the α-phase. This work will optimize the mechanical property by means of microstructural control and deepen the understanding of influence of α-phase features on the mechanical properties.