Study on hot deformation behavior and hot processing map of as-extruded TiAl alloy
Aiming at the difficulty of thermoplastic deformation of TiAl alloy,the thermal deformation behavior of as-extruded Ti-47Al-2Cr-2Nb alloy at deformation temperature of 1000-1300℃,strain rate of 0.001-1 s-1 and engineering strain of 60%was studied by using MMS-200 thermal simulator.The constitutive equation of the alloy based on strain compensation was derived by Arrhenius function model.Based on the dynamic material model,the hot processing maps of the alloy with engineering strain of 60%were established.The results show that the alloy has positive strain rate sensitivity and negative temperature sensitivity.It is found that the ideal deformation parameters are 1100-1150℃,0.001-0.05 s-1and 1200-1300℃,0.001-0.01 s-1,which breaks through the traditional recognition that TiAl alloy can only deform at high temperature and low strain rate.It is found that the alloy can still obtain better formability by suitable forming tem-perature matching with high strain rates of 0.01 and 0.1 s-1.
as-extruded TiAl alloyconstitutive modelhot processing map
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