Microstructures and mechanical properties of high performance Mg–4Y–2.4Nd–0.2Zn–0.4Zr alloy

The microstructures and mechanical properties of the high performance Mg–4Y–2.4Nd–0.2Zn–0.4Zr alloy were investigated. The results showed that the alloy was mainly composed of α-Mg, Mg24Y5 and Mg12Nd phases in the as-cast condition. After the solution treatment at 500 °C for 6 h and subsequent ageing at different temperatures, alloy exhibited the remarkable mechanical properties. The values of ultimate tensile strength, yield strength and elongation were 339 MPa, 268 MPa and 4.0% in 200 °C peak-aged condition, and 330 MPa, 265 MPa and 6.5% in 225 °C peak-aged condition, respectively. The high mechanical properties were mainly attributed to a high volume fraction of fine metastable precipitates in the matrix.

► Adding 0.2 wt.% Zn into Mg–4.0Y–2.4Nd–0.5Zr alloy.
► Zn could improve greatly the mechanical properties of Mg–4.0Y–2.4Nd–0.5Zr alloy.
► Strengthening mechanism of the peak-aged alloy was investigated.