Hot deformation and constitutive modeling of a Ti-Al-Sn-Zr-Mo-Cr-Nb alloy

Titanium alloys are the ideal structural materials for automotive and aerospace industries, and hot deformation is widely used to modify the microstructure of the alloy. In this work, a Ti-Al-Sn-Zr-Mo-Cr-Nb alloy was hot deformed at various strain rates and temperatures. The deformation behavior, microstructure, processing maps, and constitutive modeling are investigated. The results show that the hot deformation behavior of the studied alloy is sensitive to the processing parameters, the revised Johnson-Cook model with an average relative error of 1.463 %, and a correlation coefficient of 0.991 can accurately describe the hot deformation behavior of the alloy. Based on the established processing maps, the safe processing areas are 1133-1213 K, 0.004-0.1 s- 1 and 1093-1213 K, 0.001-0.004 s- 1. With the increased deformation temperature, both the fraction and size of the equiaxed alpha and lamellar alpha phases are gradually decreased, and the spheroidization degree of the lamellar alpha phase gradually decreases too. The strain rates have different influences on the evolution of alpha and (3 phases. With the increased strain rates, the fraction of recrystallized and deformed (3 phase is remarkably decreased, the fraction of sub-structured microstructures of (3 phase is obviously increased, while the fraction of deformed structures of the alpha phase is less affected.