Effect of Rolling Temperature on the Recrystallization Behavior and Texture Evolution of Mg-14gd-0.5zr Alloy

Abstract

Mg alloys containing high rare earth elements (REs) are hard to be rolled due to their low ductility at low temperatures; therefore, rolling at high temperatures is necessary. In this work, a Mg-14Gd-0.5Zr (wt.%) alloy was rolled one pass with 40% reduction at high temperatures over 450°C. The effects of rolling temperature on the microstructure and dynamic recrystallization behavior were analyzed in detail by the electron backscattered diffraction (EBSD) method. The results show that the alloy shows good rollability at high temperature due to the activity of nonbasal dislocation slip at high temperature accompanied by twining. However, dynamic recrystallization is difficult to take place because of the easy activation of mutislip system and thus more accumulated strain energy at high temperature. However, Gd segregation can partially enhance the dynamic recrystallization ratio. Static recrystallization annealing treatment at 300°C and 350°C was hard to form and coarse precipitation appeared, while static recrystallized recrystallization with large recrystallized grains took place at higher short-term interpass annealing treatment following the rolling process, and the texture evolution was discussed in this work. This result suggests that weakened Gd segregation will cause the formation of basal texture during short-term annealing treatment by the growth of dynamic recrystallized grains.

Keywords: Magnesium alloys, Hot rolling, Annealing, Recrystallization, EBSD