Effects of temperature and strain rate on the tension-compression asymmetric plastic deformation behavior of ME20M magnesium alloy: Experiments and modeling

Abstract

The tension-compression asymmetry of a rare-earth-containing alloy sheet, ME20M, is experimentally investigated along the rolling direction over a wide strain-rate range from 0.001 to 2500 s−1 and at temperatures from 213 to 488 K. The asymmetry of yield stress in tension and compression decreases with increasing temperature and decreasing strain rate. The strain-rate sensitivity of the tension-compression asymmetry during the plastic deformation stage increases with increasing temperature. It is observed that the compressive strain-hardening rate is much higher than the tensile one due to more {101-2} tension twins occurring in the compressive plastic deformation. A viscoplastic self-consistent (VPSC) model is employed to simulate the tensile and compressive stress-strain responses, deformation texture, and deformation mechanism evolution over wide ranges of strain rates and temperatures. Results indicate that the VPSC model is capable of capturing the macroscopic plastic deformation characteristics of ME20M alloy. Tensile plastic deformation is dominated by slip at strain rates up to 103 s−1, and basal slip and tension twinning are the main deformation modes in compressive plastic deformation. Effects of strain rate and temperature on the main plastic deformation mechanism of ME20M alloy are insignificant within the tested rate and temperature ranges.