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研究了Si含量对铸态Mg-12Al-12Zn-x Si(x=1,2,4;wt%)合金显微组织和力学性能的影响。结果表明,加入Si元素后,合金主要由α-Mg基体、β-Mg17Al12相、Mg2Si相和Mg2Zn11相组成;随Si含量从1%增加到4%,合金中的Mg2Si颗粒从少量的多边形块状、花瓣状转变为大量的多边形块状、条棒状,最后转变为多边形块状和粗大的骨骼状;且Si含量为2%时,Mg2Si相颗粒呈相对弥散分布;此时,合金的室温和高温抗拉强度、屈服强度和伸长率达到最大值。合金的室温拉伸断裂形式为准解理脆性断裂。
The effects of Si content on the microstructure and mechanical properties of as-cast Mg-12Al-12Zn-xSi (x = 1,2,4; wt%) alloys were investigated. The results show that the alloy mainly consists of α-Mg matrix, β-Mg17Al12 phase, Mg2Si phase and Mg2Zn11 phase after addition of Si. With increasing Si content from 1% to 4%, the Mg2Si particles in the alloy grow from a small amount of polygonal block , The petal-shaped into a large number of polygonal block, rod-like, and finally transformed into polygonal massive and coarse bone; and Si content of 2%, Mg2Si phase particles were relatively dispersed distribution; at this time, the alloy at room temperature and high temperature Tensile strength, yield strength and elongation reached its maximum. Tensile fracture at room temperature in the form of quasi-cleavage brittle fracture.