Influence of the initial state on the microstructure and mechanical properties of AX41 alloy processed by ECAP

This study investigates the influence of the initial state of the commercial AX41 magnesium alloy on the microstructure evolution and mechanical properties after equal-channel angular pressing. Two initial conditions, an as-cast one with a grain size of 200 μm and a random crystallographic texture, and an extruded one having a grain size of 10 μm and a strong fibre texture, are compared. ECAP processing was performed at the temperature of 220 °C up to 8 passes via route BC. A much smaller grain size was obtained in the ECAP-processed as-cast material compared to the extruded one. This difference was attributed to the different evolution of the dislocation density and its fractions in different slip systems. Consequently, different refinement mechanisms were dominant in the later stage of ECAP processing. It was shown that ECAP processing leads to the formation of similar crystallographic textures for both initial states, having dominant basal texture component. The mechanical properties investigation showed improvement in the microhardness, tensile strength and elongation in both ECAP-processed samples.