Magnesium alloys is known to be the lightweight high strength material, are attractive for applications in electronics, aeronautics, astronautics and automobile industries [1–3]. However, the low strength and poor thermal stability limit their applications. Magnesium alloys containing RE element show good precipitation strengthening compared with the conventional AZ31, ZK60 and AZ80 magnesium alloys [4–6]. The addition of Zn to Mg–RE alloys can also further improve the mechanical properties due to solution, aging and long period stacking order (LPSO) structures strengthening [7–9], so the Mg–RE–Zn–Zr alloys have been attracting much more attentions from the researches [10–11].