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The microstructure and tensile properties of the as-cast and solution treatment Mg-4.5Zn-1Y-xNd-0.5Zr (x=0,1 wt.%,2 wt.%,3 wt.%) alloys were investigated.The results showed that the microstructure of Mg-4.5Zn-1Y-0.5Zr alloy consisted of α-Mg,Zn-Zr,W (Mg3Y2Zn3) and I (Mg3YZn6) phases.With the addition of Nd,I-phase disappeared and Mg3Y2Zn3 phase changed into Mg3(Nd,Y)2Zn3 phase.When the content of Nd reached 3 wt.%,T phase,i.e.,ternary Mg-Zn-Nd phase,formed.In addition,with the increase of Nd content in the alloys,the secondary dendritic arm spacing decreased,while the amount of intermetallic phases increased.For as-cast Mg-4.5Zn-1Y-xNd-0.5Zr alloys,after solution treatment,microsegregation was eliminated and the shape of eutectic structure of α-Mg+W transformed from lamellar into spherical.The tensile strength and elongation of Mg-4.5Zn-1Y-3Nd-0.5Zr alloy were increased from 219.2 MPa and 11.0% to 247.5 MPa and 20.0%,respectively.
The microstructure and tensile properties of the as-cast and solution treatment Mg-4.5Zn-1Y-xNd-0.5Zr (x = 0,1 wt.%, 2 wt.%, 3 wt.%) Alloys were investigated.The results showed that the microstructure of Mg-4.5Zn-1Y-0.5Zr alloy consisted of α-Mg, Zn-Zr, W (Mg3Y2Zn3) and I (Mg3YZn6) phases. By the addition of Nd, I-phase disappeared and Mg3Y2Zn3 phase changed into Mg3 (Nd, Y) 2Zn3 phase. Where the content of Nd reached 3 wt.%, T phase, ie, ternary Mg-Zn-Nd phase, formed. For as-cast Mg-4.5Zn-1Y-xNd-0.5Zr alloys, after solution treatment, microsegregation was eliminated and the shape of eutectic structure of α-Mg + W transformed from lamellar into spherical. tensile strength and elongation of Mg-4.5Zn-1Y-3Nd-0.5Zr alloy were increased from 219.2 MPa and 11.0% to 247.5 MPa and 20.0%, respectively.