Investigation of the workability of pilot ingot of high Nb containing TiAl based alloy

Thermomechanical processing parameters for high Nb containing TiAl based alloy were investigated by thermal simulation tests. According to the results can forging processes of pilot ingots were conducted, and the microstructures of the ingots before and after hot working were analyzed by optical microscopy and scanning electron microscopy (SEM). The results showed that the high Nb containing TiAl alloy had good deformability and the deformation resistance decreased with the increase of temperature and the decrease of strain rate. Good appearance, crack-free pancakes can be obtained by can forging at the temperature of α + γ phase region for the ingots with a height-to-diameter (H/D) ratio of 1.10-2.13. The as-forged microstructures consisted of the refined duplex microstructure for the major part of the pancakes with retained lamellar colonies and partially recrystallized grains for the near surface zone of the pancakes.