Sb含量对铸态Mg-4Al-1Zn-1Si合金组织与性能的影响

Effects of Sb Content on Microstructure and Mechanical Properties of As-cast Mg-4Al-1Zn-1Si Alloy

研究了合金元素Sb对Mg-4Al-1Zn-1Si合金组织和性能的影响。结果表明:加入0.25wt%Sb时,合金中形成了Mg3Sb2相,原来大量聚集于晶界的粗大汉字状Mg2Si相颗粒转变为相对细小的汉字状Mg2Si相颗粒,呈弥散分布于晶界及晶内,同时出现了少量多边形块状Mg2Si相颗粒,此时合金的力学性能有所提高;当Sb为0.5%时,Mg2Si相颗粒尺寸迅速减小,转变为球状或短棒状,此时,合金的室温和高温抗拉强度、屈服强度和伸长率均达到最大值;当Sb含量为0.75%时,Mg2Si相颗粒尺寸未见明显变化,但又发生聚集现象;当Sb含量为1.0%时,Mg2Si相颗粒又转变为尺寸较大的汉字状颗粒,此时合金的力学性能发生下降。

The effects of Sb modification on the microstructure and properties of Mg-4AI-IZn-ISi alloy were investigated. The result show that the Mg3Sb： phase generates in the alloy by the addition of 0.25wt% Sb. Large numbers of coarse Chinese script shaped Mg2Si phases which accumulated originally in the grain boundary are refined, which dispersed in the grain boundary and inside. Meanwhile, a few of polygonal block Mg2Si particles appear, and the mechanical properties are improved. When the content of Sb is 0.5wt%, the Mg2Si particle size decreases rapidly and changes into block and rod shapes. At the same time, the room temperature and elevated temperature mechanical properties of the alloy can reach the maximum. When the content of Sb is 0.75wt%, the MgaSi particle size does not change obviously, but they start to aggregate. When the content of Sb is 1.0wt%, the Mg2Si phases change into large Chinese script shaped again, and the mechanical properties of the alloy reduce.