Effect of Extrusion Temperatures on Microstructures and Mechanical Properties of Mg-3Zn-0.2Ca-0.5Y Alloy

After solution treatment, the Mg-3Zn-0.2Ca-0.5Y alloy was subjected to extrusion at various temperatures and extrusion defects, microstructures and mechanical properties of as-extruded samples were studied in detail. The results show the extrusion temperature has a slight effect on DRXed grain size due to the presence of Y-containing phase with a good thermal-stability. On the contrary, the mechanical properties of as-extruded alloys are remarkably influenced by dynamic recrystallization degrees promoted by extrusion temperatures. A good formability of as-extruded bars with an optimal mechanical properties and fine-grained microstructure was obtained by extrusion at 250 °C and the mechanical performances are significantly superior to those of hot-rolled ZK60 obtained at the same temperature. In this paper, the magnesium alloy with fine-grained (<5 μm), high ductility (>30%) and high strength (>250 MPa) was fabricated easily by a simple extrusion process.