TITANIUM ALUMINIDE ALLOY MATERIAL FOR HOT FORGING, FORGING METHOD FOR TITANIUM ALUMINIDE ALLOY MATERIAL, AND FORGED BODY

摘要

This TiAl alloy material for hot forging has a chemical composition comprising, in terms of atomic ratio, 43.0-45.0% of Al, 4.0-6.0% of Nb, 1.5-3.5% of Cr, and a remainder of Ti and unavoidable impurities. In addition, the TiAl alloy material for hot forging may optionally contain boron. The TiAl alloy material for hot forging is prepared, the temperature is held within a phase equilibrium temperature range for one of the β phase, the (β+α) phase, and the (β+α+γ) phase indicated in the TiAl alloy phase diagram, and the TiAl alloy material is forged in a non-oxidizing atmosphere. First and second heat treatments are performed after forging. The present invention improves isothermal forgeability in a TiAl material and makes it possible to perform hot forging at a lower forging temperature.