EFFECTS OF THERMO-MECHANICAL TREATMENTS ON MICROSTRUCTURE OF Ti-43Al-9V-Y ALLOY

Ti-43Al-9V-Y alloy billets was prepared by the quasi-isothermal canned forging processing, and effect of heat treatment processes on the microstructure of as-forged Ti-43Al-9V-Y alloy was investigated. The results show that, as-forged Ti-43Al-9V-Y alloy has streamline microstructure including a large number of recrystallized grains and broken lamellae, and different heat treatment processes were employed to obtain different microstructures of Ti-43Al-9V-Y alloy. After heat treatment at 1250°C, the microstructure of as-forged Ti-43Al-9V-Y alloy becomes γ+B2 microstructure. Comparing with the microstructure after HT of 1250°C/30 min, the precipitation of B2 lath phase in γ equiaxed grains increased and γ grains refined after HT of 1280°C/30min or 1320°C/30min. However, after the heat treatment of 1300°C/30 min, the duplex microstructures can be gained.