Deformation mechanism temperature-dependence of AZ31 magnesium alloy

Abstract

The deformation behavior of AZ31 Mg alloy is studied here in relation to the temperature. A rolled plate with a thickness of 50 mm was first homogenized at 400 °C for 4 h before preparing test specimens with the tensile axis parallel to the rolling direction (RD). A series of tensile tests was then carried out at a strain rate of 10−2/s together with load relaxation tests to obtain flow curves in terms of the stress and strain rate at room temperature (RT), 100 °C, 200 °C, and 300 °C. The flow curves were found to represent the usual grain matrix deformation (GMD) behavior, consisting of the accumulation and relaxation of glide dislocations at temperatures of less than 100 °C. At temperatures greater than 200 °C, grain boundary sliding (GBS) was found to play an important role, as described in theories related to an internal variable. The GBS could be characterized as a non-Newtonian viscous flow with a power index value of M g = 0.5.