Microstructure and mechanical properties of high performance Mg–Gd based alloys

The Mg–12Gd–4Y–2Nd–0.3Zn–0.6Zr (wt.%) alloy was prepared by casting technology, and the structure, age hardening behavior and mechanical properties of the alloy have been investigated. The results demonstrated that the alloy was composed of α-Mg matrix, a lot of dispersed Mg24RE5 (RE = Gd/Y/Nd) and Mg5RE precipitates in the as-cast and the T6 state alloys. The alloy exhibited remarkable age hardening response and excellent mechanical properties from room temperature (RT) to 300 °C by optimum solid solution and aging conditions. The ultimate tensile strength, yield strength and elongation of the alloy at peak hardness were 310 MPa, 280 MPa and 2.8% at RT, and 293 MPa, 261 MPa and 5.8% at 300 °C, respectively. The high mechanical properties were mainly attributed to the fine microstructure, fine metastable precipitate and the dispersed precipitates in the matrix.