Mg–Al–Mn magnesium alloy processability and its extrusion simulation of complex profiles for automotive battery trays

Abstract

Although magnesium alloy thin-walled profiles possess significant lightweight potential for new energy vehicle battery trays, their processing has not been reported previously. This study systematically investigates the workability of an Mg-7.5Al-0.5Mn-0.3Ce alloy (a novel composition specifically designed for lightweight battery tray applications) and its extrusion process. Hot compression tests are performed to characterize the rheological behavior, resulting in the development of a strain-compensated Arrhenius-type constitutive model incorporating Zener-Hollomon parameters. The model demonstrates excellent predictive capability, with a correlation coefficient (R) of 0.9938 and an average absolute relative error (AARE) of 3.73%. The combination of this Arrhenius model with processing maps identifies an optimal processing window (approximately 723 K at low strain rates with power dissipation efficiency η >0.3), providing theoretical guidance for hot deformation process optimization. The use of custom-designed planar manifold combination dies, integrated with HyperXtrude numerical simulation, achieves uniform material flow at the profile outlet (maximum velocity difference: 0.5 mm/s). Experimental validation shows a close agreement between simulation and experimental extrusion results. Microstructural characterization confirms complete grain fusion in the weld seam with no detectable surface coarse grains. Mechanical tests demonstrate superior properties in the weld zone (tensile strength: 321.9 MPa) compared to the base material (310.6 MPa). These findings validate the optimized manifold die extrusion parameters, enabling high-quality forming of thin-walled profiles with large width-to-thickness ratios. This work provides a technical foundation for magnesium alloy applications in new-energy vehicle battery trays.