Effects of plastic deformation of solid phase on mechanical properties and microstructure of wrought 5A06 aluminum alloy in directly semisolid thixoforging

Abstract

Abstract A directly thixoforged technology of wrought 5A06 alloy with low-cost and short-process was proposed to form a bracket-shape component. The results showed that complex components with a minimum wall thickness of 6 mm, a draft angle of only 1° and an allowance of 1 mm were thixofored successfully. The billet’s shape had a slight influence on the filling process of the semisolid slurry during the thixforging. Solid grains in the microstructure of the thixoforged parts exhibited a large deformation degree. It led to an obvious improvement of the mechanical properties of the thixoforged parts. The yield strength (YS) varied from 129.28 MPa to 149.63 MPa, the ultimate tensile strength (UTS) varied from 293.92 MPa to 322.3 MPa, and the elongation varied from 18% to 41.48%. The YS is slightly higher than that of the rolled plate, the elongation is much higher than that of the rolled plate, and the UTS is slightly lower than that of the hot-rolled plate. The increase of plastic deformation degree caused by larger ellipsoid grains is beneficial to improve the mechanical properties of the thixoforged components. The significant improvement of elongation was attributed to homogeneous re-precipitation of the β phase (Mg5Al8) in the thixoforged process.