EFFECT OF STRAIN RATE ON DYNAMIC RECRYSTALLIZATION IN A MAGNESIUM ALLOY UNDER COMPRESSION AT HIGH TEMPERATURE

摘要

Interrupted uniaxial compression tests were performed on anextruded Mg-Al-Mn magnesium alloy (AM30) at 450°C andvarious strain rates of 0.001 s~(-1), 0.1 s~(-1), 0.5 s~(-1) and 0.8 s~(-1). Textureand microstructure evolution were examined using electron backscattered diffraction (EBSD) and X-ray diffraction (XRD)techniques. Twinning was found to be ubiquitous at hightemperature but provided that a highly enough strain rate wasapplied. The results show that the deformation microstructureevolves with strong dependence on the strain rate as twinningtriggers and non-basal slips become harder. Schmid's factor andslip traces analyses elucidated the driving forces controllingdynamic recrystallization mechanisms and emphasized on the roleplayed by extension twinning and non-basal slips.