SUPERPLASTIC DEFORMATION OF TiAl BASED ALLOY
(1.National Key Laboratory For Powder Metallurgy, Central South University of Technology, Changsha 410083, P. R. China;
2.University of Aeronautics and Astronautics Nanjing, Nanjing210016, P. R. China)
2.University of Aeronautics and Astronautics Nanjing, Nanjing210016, P. R. China)
Abstract: The tensile properties of thermomechanically processed Ti-33Al-3Cr-0.5Mo (mass fraction, %) alloy were determined at 1000℃. In an initial strain rate range of 2.0×10-4~6.0×10-4s-1 superplastic deformation behaviour of fine grained specimens was observed, and the relative elongations ranging from 200%~305% were obtained. After deformation grain size became finer, a lot of dislocations were found. Combined with TEM observations, it was suggested that superplastic deformation was controlled by grain boundary sliding accomodated by movement of dislocation and dynamic recrystallization.
Key words: superplastic deformation TiAl alloy dynamic recrystallization dislocation