Static coarsening behavior of equiaxed α phase in Ti−8Al−1Mo−1V alloy

To get a deep understanding of the evolution behavior of equiaxed α phase in Ti−8Al−1Mo−1V alloy during annealing, its static coarsening mechanism was studied based on the calculations of coarsening exponent n and the activation energy for α boundary migration. The result of n=6 indicates a special coarsening mechanism of equiaxed α phase. The activation energy for α boundary migration is calculated to be 138 kJ/mol, which is close to the activation energy for grain growth of pure α-Ti. It is revealed that the coarsening of equiaxed α can be mainly attributed to the self-diffusion of Ti atoms across the α/α boundaries. Based on the experimental findings, a static coarsening kinetics model of equiaxed α grains in the α+β field is established. At last, the effects of the coarsening behavior of equiaxed α on tensile properties were studied.