通过光学显微镜、力学万能试验机、X射线衍射仪和扫描电镜分析了Mg含量对Al-20Si铝合金显微组织和力学性能的影响。结果表明:合金中主要有α-Al、共晶硅、初生硅和Mg2Si等相存在,随着Mg含量的增加初生硅数量逐渐减少,并且变得细小;抗拉强度逐渐增加,而伸长率呈先下降后上升的趋势,硬度与伸长率的变化趋势相反。 The effects of Mg content on the microstructure and mechanical properties of Al-20Si aluminum alloy were analyzed by optical microscope, universal mechanical testing machine, X-ray diffraction and scanning electron microscopy. The results show that there are mainly α-Al, eutectic silicon, primary silicon and Mg2Si in the alloy. The content of primary silicon decreases with the increase of Mg content, and becomes smaller; the tensile strength increases gradually, while the elongation After the first decline, the trend of rising, the trend of hardness and elongation changes the opposite.