Microstructure and mechanical properties of extruded Mg-6.5Gd-1.3Nd-0.7Y-0. 3Zn alloy

The Mg-6.5Gd-1.3Nd-0.7Y-0.3Zn alloy ingot and sheet were prepared by casting and hot extrusion techniques, and the microstructure, age hardening behavior and mechanical properties were investigated. The results show that the as-cast alloy mainly contains α-Mg solid solution and compounds of Mg ₅RE and Mg₂₄RE₅ (RE=Gd, Y and Nd) phases. The grain size is refined after hot extrusion, and the Mg₅RE and Mg ₂₄RE₅ compounds are broken during the extrusion process. The extruded alloy exhibits remarkable age hardening response and excellent mechanical properties in the peak-aging state. The ultimate tensile strength, yield strength and elongation are 310 MPa, 201 MPa and 5.8 at room temperature, and 173 MPa, 133 MPa and 25.0% at 300 °C, respectively.