SUPERPLASTIC BEHAVIOR OF HOT-FORGED TiAl-BASED ALLOY
(State Key Laboratoryfor Powder Metallurgy,Central South University of Technology, Changsha 410083, P. R. China)
Abstract: Aγ-TiAl based material with a composition of Ti-33Al-3Cr-0.5Mo(mass fraction, %) was hot forged to produce fine-grained microstructure with good homogeneity. Samples of the hot-forged material were tested at strain rates ranging from 8×10-5s-1to 8×10-4s-1and temperatures between 1 000℃and 1 075℃to investigate its superplastic behavior. Results showed the occurrence of strain hardening and highm values which led to the good superplasticity of this alloy. Optimum superplastic forming conditions were at 1 075℃and a strain rate of 8×10-5s-1. Under these conditions, the maximum elongation to fracture of 517% was achieved.
Key words: TiAl deformation superplasticity strain rate