The problems of energy and environm

The problems of energy and environment are becoming the focus of the world at the present time and the lightweight design is an effective solution. Mg-based alloys exhibit the notable advantages to the automotive and aerospace industries as structural partsdue to their low densities and high strength per weight ratios. However, Mg alloys application has been limited to some components because of their low strength and poor heat resistance [1,2]. Rare earths, as important alloying elements, are often added in Mg alloys to improve their strength and heat resistance. WE type (Mg–Y–Nd–Zr) alloys have been successfully developed and applied in airplane [3]. It has been confirmed that Gd element can obviously improve the strength of Mg alloys at elevated temperature because of the strengthening phase stability [4]. Recent years, some Mg–Gd alloy systems with different Nd and Y content have been investigated as a research focus [5–8]. For example, Mg–8Gd–2Nd–1Y–0.6Zr alloy exhibits remarkable age-hardening behavior and reveals superior mechanical properties in as-cast and T6 state [9]. In the present work, the Mg–5Y–3Nd–0.6Zr–xGd alloys were prepared, and the structures and mechanical properties of the as-cast alloys were investigated.