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The effects of combined addition of 0.6 wt.% Nd and 0.4 wt.% Y on the microstructure and mechanical properties of Mg-7Zn-3Al alloy were investigated.The results indicated that the Nd and Y addition led to obvious dendrite coarsening.However,it could modify the morphology and distribution of-Mg 32(Al,Zn) 49 intermetallics.Moreover,Al 2 REZn 2 phase could be introduced into the alloy with the Nd and Y addition.With the effective second-phase strengthening,the ultimate tensile strength and elongation in as-cast state can be improved by the Nd and Y addition.After ageing treatment,the alloy with the Nd and Y addition exhibited better precipitation strengthening effects by forming finer MgZn 2 and Mg 32(Al,Zn) 49 precipitates into the-Mg matrix.As a result,the yield and ultimate strength of Mg-7Zn3Al-0.6Nd-0.4Y alloy could be increased to 182 and 300 MPa by peak-ageing treatment.
The effects of combined addition of 0.6 wt.% Nd and 0.4 wt.% Y on the microstructure and mechanical properties of Mg-7Zn-3Al alloy were investigated. The results indicated that the Nd and Y addition led to obvious dendrite coarsening. However, it could modify the morphology and distribution of-Mg 32 (Al, Zn) 49 intermetallics. Moreover, Al 2 REZn 2 phase could be introduced into the alloy with the Nd and Y addition .With the effective second-phase strengthening, the ultimate tensile strength and elongation in as-cast state can be improved by Nd and Y addition. After aging treatment, the alloy with the Nd and Y addition successfully improved precipitation strengthening effects by forming finer MgZn 2 and Mg 32 (Al, Zn) 49 precipitates As the result, the yield and ultimate strength of Mg-7Zn3Al-0.6Nd-0.4Y alloy could be increased to 182 and 300 MPa by peak-aging treatment.