Isothermal deformation of gamma titanium aluminide

1. During isothermal forming the microstructure affects workability limits. The processing window for the finer grained hot extruded and heat treated material is larger than that for the as-cast material in terms of the minimum temperature, highest strain rate, and maximum strain under which deformation occurs without observable macroscopic failure. 2. The processing limits at a final strain of 0.7 (50% upset) are: for conventionally cast material (0.75″, 19mm dia.), strain rate maximum between 0.1 and 1s-1, and minimum temperature of 950°C; for material extruded 16:1 and heat treated material, strain rate maximum of 1s-1, and minimum temperature of 700°C, and for P/M material, strain rate maximum of 1s-1, and minimum temperature of 700°C.