Intricate interplay between shear stress and extrusion temperature in Mg−Al composite rods

The Mg−Al composite rods of aluminum core-reinforced magnesium alloy were prepared by the extrusion−shear (ES) process, and the microstructure, deformation mechanism, and mechanical properties of the Mg−Al composite rods were investigated at different extrusion temperatures and shear stresses. The experimental results show that the proportion of dynamic recrystallization (DRX) and texture for Al and Mg alloys are controlled by the combination of temperature and shear stress. The texture type of the Al alloys exhibits slight variations at different temperatures. With the increase of temperature, the DRX behavior of Mg alloy shifts from discontinuous DRX (DDRX), continuous DRX (CDRX), and twin-induced DRX (TDRX) dominant to CDRX, the dislocation density in Mg alloy grains decreases significantly, and the average value of Schmid factor (SF) of the basal <a> slip system increases. In particular, partial grains exhibit a distinct dominant slip system at 390 °C. The hardness and thickness of the bonding layer, as well as the yield strength and elongation of the Mg alloy, reach their maximum at 360 °C as a result of the intricate influence of the combined temperature and shear stress.