Zr对铸造MgZn5Nd3.5合金组织和性能的影响

制备了不同Zr含量的MgZn5Nd3．5ZrX合金，研究了Zr元素对合金晶粒大小及铸态力学性能的影响。显微组织观察表明，当w（Zr）≤0．8％时，合金晶粒度随Zr含量增加而减小；当w（Zr）〉0．8％时，合金晶粒度基本保持不变。力学性能测试表明，Zr元素的添加，使合金铸态下的抗拉强度和伸长率均得到了提高。拉伸断口SEM形貌分析表明，合金断裂方式由准解理断裂向韧性断裂发生转变。

Effects of Zr on Microstructure and Properties of MgZn5Nd3.5 Alloy

The effects of different Zr contents on the grain size and as-cast mechanical properties of the MgZn5Nd3.5 alloy were studied.Microstructural observation indicates that grain size is increased with increase in the Zr content in case of Zr content less than 0.8%,while the grain size is somewhat changed with that in case of Zr content more than 0.8%.From the mechanical property measurements indicate that Zr addition can improve as-cast tensile strength and elongation of the alloy.SEM analysis shows that alloy rupture changes from quasi-cleavage fracture to ductility fracture.