Microstructure Evolution and Mechanical Properties of AQ80 Alloy During Forward Extrusion and Twist Deformation

A new severe plastic deformation technique, forward extrusion and twist deformation, was adopted to manufacture magnesium (Mg) alloys at different temperatures. The microstructure evolution and mechanical properties of extruded AQ80 alloy were investigated. The strain distribution in FETD extrusion was simulated with finite element simulation software. The extruded samples exhibit finer grain sizes, weaker basal textures, higher recrystallized volume fractions and higher strengths than the traditional forward extrusion samples. This technology can refine the microstructure and improve the mechanical properties of Mg alloys. At lower temperatures, the grain size is smaller with a finer second phase, which is detected as Mg17AL12. Mg17AL12 has a particle-stimulated nucleation effect and a retarding effect on grain growth, resulting in much finer DRXed grains. Due to the effects of fine-grained strengthening and second phase strengthening, the strength and elongation of AQ80 alloy can be improved significantly.