Precipitation and its effect on age-hardening behavior of as-cast Mg–Gd–Y alloy

Microstructures evolution of Mg–7Gd–3Y–0.4Zr (wt.%) alloy during aging at 200 °C was investigated by using optical microscope (OM), scanning electron microscope (SEM) and transmission electron microscope (TEM). The results showed that the alloy could exhibit remarkable age-hardening response by optimum solid solution and aging conditions. Especially, the highest Vickers hardness (HV) of this alloy was obtained when it was aged at 200 °C for 120 h, which was mainly attributed to a dense distribution of β′ precipitation in the matrix.