Formability of Ti14 alloy during semisolid deformation

The semisolid formability for Ti14, an α+Ti2Cu alloy, is compared with the conventional warm formability from the point of forgeability. The forgeability is evaluated by upsetting and die forging tests. The results show that excellent upsettability with the upsetting reduction in height of 70-85% and low upsetting force could be obtained in semisolid state ranging from 1000 to 1100°C, which is better than that in conventional processing. Die forging tests also show excellent workability with a forging ratio of 75% at the temperature range of 1000-1050°C. It can be concluded that the existence of liquid may serve to relax the stress concentrations caused by solid deformation, which causes low deformation resistance and results in improvement of forgeability. Furthermore, dynamic recrystallisation occurred during thixoforging, and the grain refinement was attained, which also results in the improvement of the semisolid formability.