Incremental deformation and the forgeability of gamma titanium aluminide

Hot die forging has been undertaken on cube shaped workpieces of cast two-p hase gamma titanium aluminide. The inhomogeneous as-cast microstructure cau ses non-uniform deformation and low ductility. Incremental deformation usin g hot dies aims to break down large alpha (2)+gamma lamellae in the structu re by using an accumulation of small amounts of deformation with interspers ed with periods for material recovery. The effect of various forms of incre mental deformation, with or without subsequent isothermal forging, on micro structure is discussed. It is shown that the use of hot-die forging to refi ne microstructure is limited by chilling of the workpiece and loss in ducti lity. (C) 2001 Published by Elsevier Science Ltd.