Effect of Zn on the Mechanical Properties and Microstructure of as-Cast and Solution-Treated Mg–6Y–2Nd–1Gd–0.5Zr Alloys

The effect of varying Zn contents (0, 0.4, and 0.8 wt.%) on the microstructure and mechanical properties of an Mg–6Y–2Nd–1Gd–0.5Zr alloy was systematically evaluated to improve the above characteristics. An as-cast alloy is shown to mainly consist of α-Mg, Mg 24 Y 5 , Mg 12 Nd, and Mg 5 Gd phases. An addition of Zn to the alloy results in the Mg 12 YZn phase formation and grain refinement. An increase in a Zn volume from 0.4 to 0.8 wt.% brings about a narrower solidification temperature range. After solution treatment, Mg 12 Nd and Mg 24 Y 5 mainly disappear, but a Mg 12 YZn content grows. The tensile strength, yield strength, and elongation of a solution-treated Mg–6Y–2Nd–1Gd–0.5Zr–0.4Zn alloy are 284 MPa, 218 MPa, and 6.5%, respectively.