Superplastic Deformation Based on Strain-induced and maximal m Value in TC4-DT Titanium Alloy

The superplastic deformation characteristics of TC4-DT titanium alloy were investigated at 850-900℃ and Pre-stain of 1. 0-2. 0 by the method of strain-induced superplastic deformation based on the maximal m value method. Then the optimum process parameters were determined. The results show that the elongations of the alloy increase and then decrease with the increasing of the deformation temperature under the same pre-stain. The elongations of the alloy increase and then decreased with the increasing of the prestain at the same temperature. Dynamic recrystallization obviously occurred in the alloys superplastic deformation. The main deformation mechanism of strain-induced superplasticity deformation based on maximal m value is grain boundary sliding and the anxiliary mechanism of deformation is dynamic recovery and recrystallization. The best process parameters of the strain-induced superplastic deformation were the deformation temperature of 870℃ and pre-strain of 1. 5. and the elongation ratio could reach 1033%