Microstructures and Mechanical Properties of Hot-Rolled Mg-Al-Ce Ternary Alloy Sheets with Different Al Contents

To develop wrought magnesium alloy sheet with excellent comprehensive mechanical property and low cost, as-cast Mg-xAl-4Ce (x = 3 similar to 6) alloy samples obtained by gravity casting were first homogenized, and then hot-rolled at 648 K with 70% deformation. The microstructures and phase compositions were analyzed by SEM, TEM, EBSD and XRD, and meanwhile, the hardness and tensile mechanical properties at ambient temperature were tested. The results show that the as-cast structures are mainly composed of alpha-Mg matrix, acicular Al11Ce3, blocky Al2Ce and irregular Mg17Al12 phases. By increasing the Al content, the Al2Ce and Mg17Al12 phases gradually increase in the number and size, while the Al11Ce3 phase first increases, and then decreases in the number. After hot rolling, the Al11Ce3 phase broken into short rods distributes in streamline along rolling direction, and the slightly refined Al2Ce phase still randomly distributes. By increasing the Al content, the significantly enhanced strength and hardness gradually increase, while the plasticity first increases, and then decreases. For the Mg-6Al-4Ce rolled sheet with the best comprehensive properties, the yield strength, ultimate tensile strength, elongation to fracture and hardness can reach 192 MPa, 273 MPa, 13.0% and 55.0 HV, respectively.