Effect of Extrusion Temperature on Microstructure and Mechanical Properties of Mg–Al–Zn Alloy Prepared by Solid‐State Recycling of Mixed Waste Chips

Abstract

The recycled Mg–Al–Zn alloys are successfully fabricated through solid‐state recycling of mixed waste chips, including cold pressing and hot extrusion. The effects of extrusion temperature on the microstructure evolution, slip mode, tensile properties, and hardness are studied. The homogeneous fine dynamic recrystallization (DRXed) grains with an average grain size of less than 13.1 μm can be obtained at four different extrusion temperatures (250, 300, 350, and 400 °C). The average grain size of the DRXed grains continuously increases with the rising extrusion temperature. However, the yield strength (YS), ultimate tensile strength (UTS), and elongation to failure (EL) of the recycled alloys increase first and then decrease. The recycled Mg–Al–Zn alloys at 350 °C demonstrate excellent mechanical properties with the YS of 134.6 MPa, UTS of 286.2 MPa, EL of 7.4%, and Vickers hardness of 75.2 HV, respectively. In addition, the slip mode is transformed from the previous basal slip to the coactivation of multiple slips composed of the basal slip, prismatic slip, and pyramidal slip with the rising extrusion temperature.