Dry sliding wear tests were performed on a Mg–10Y–4Gd–1.5Zn–0.4Zr alloy using a Ball-on-Flat type wear apparatus against an AISI 52100 type bearing steel ball counterface. The wear rates were measured within a load range of 3–25 N, a sliding speed range of 0.03–0.3 m/s and a sliding temperature range of 25–200 °C at a constant sliding distance of 400 m. The morphologies of the worn surfaces and wear debris were studied by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS). Comparatively, the wear properties of a hypereutectic Al–Si aluminium alloy under the same condition were measured. The results indicate that the wear rates of Mg–10Y–4Gd–1.5Zn–0.4Zr alloy are lower than that of cast+T6 AC9B aluminium alloy. The dominant mechanism of cast+T6 Mg–10Y–4Gd–1.5Zn–0.4Zr alloy is abrasion wear mixed with other wear mechanisms, which tends to be an abrasion and plastic deformation wear at high normal load such as 10–25 N, abrasion and plastic deformation wears with small participation of delamination and oxidative wears at high sliding speed such as 0.12–0.3 m/s, and an oxidative and abrasion wear at high test temperature such as 100–200 °C. The Mg12Y1Zn1 phase in Mg–10Y–4Gd–1.5Zn–0.4Zr alloy plays an important role in the wear rate.
