Packed forging and microstructure optimization of β-solidified TiAl alloy

The displacement-load curves of Ti-43Al-5(Nb,Mo,B) alloy isothermally compressed at different strain rates and temperatures on Gleeble-1500D thermal-simulation machine were investigated.The results indicated that the load increased sharply first,and then kept constant,and finally increased again as the displacement increased continuously.A crack-free pancake was obtained when the ingot was packing forged at 1150℃ and with strain rate of 0.1/s.The microstructure of the pancake consisted of major kinked/broken lamellae and dynamic recrystallization grains,minor residual β phase and remnant lamellae.After annealed at 1180℃ for 5 hours,a homogeneous microstructure with fine and equiaxed grains was obtained.With elimination of the residual β phase,the uniformity of the microstructure was greatly improved as well.