Experimental and numerical investigation into rectangular tube extrusion of high-strength magnesium alloy

In order to reduce weight in air and ground vehicles, hollow magnesium alloy profiles are widely concerned. This research was aimed to extrude the tubes of newly developed high-strength alloy Mg–Al–Zn-RE by the porthole die. The magnesium alloy tubes with rectangular sections were extruded at the conditions optimized through the finite element simulations of extrusion processes. The microstructure observation indicated that the magnesium alloy underwent complete dynamic recrystallization (DRX) during the hot extrusion. Moreover, plenty of fine particles dynamically precipitated from the magnesium matrix were distributed on the grain boundaries. Undergoing the dramatical evolution of microstructure, the fine grains and particles significantly strengthened the extruded magnesium alloy. The tensile test demonstrated that extruded tubes possessed maximum ultimate tensile strength 406 ± 7 MPa and elongation 21.8 ± 1.0% at the optimal extrusion parameters. © 2020 The Authors