Microstructural evolution and age‐hardening behavior of quasicrystal‐reinforced Mg–Dy–Zn alloy

Microstructural evolution and age‐hardening behavior of Mg–2Dy–6Zn (at%) alloy during solid‐solution and aging treatment were investigated. The microstructure of as‐cast alloy is composed of α‐Mg, Mg 3 DyZn 6 (I) phase, Mg 3 Dy 2 Zn 3 (W) phase, Mg(Zn,Dy) phase and a small amount of Mg 0.97 Zn 0.03 phases. After solid‐solution treatment (480 °C, 12 h), all the I phases and most W phases dissolve into α‐Mg matrix and the remainder W phases transform into Mg(Dy,Zn) phase and MgDy 3 phase. During aging treatment, I phase and small amounts of W phases co‐precipitate from α‐Mg matrix, respectively. The alloy exhibits a peak hardness of HV 77.5 at 200 °C for 8 h. The excellent age‐hardening behavior of alloy is mainly attributed to the co‐precipitation strengthening of I and W phases.