基于液淬试样组织观察的结果， 对ＳｉＯ２ 与ＭｇＬｉ 合金熔体反应动力学进行了分析。建立了ＳｉＯ２与ＭｇＬｉ 熔体反应的动力学模型， 提出了控制粒子尺寸及其在熔体分布的措施。得出了ＳｉＯ２ 与ＭｇＬｉ 熔体反应的速度表达式， 确定了Ｍｇ２Ｓｉ 的形成位置。结果表明： ＳｉＯ２ 与ＭｇＬｉ 合金熔体的反应是分两步进行的， 即首先在界面处反应生成ＭｇＯ 与Ｓｉ， 而后Ｓｉ 与Ｍｇ 反应生成Ｍｇ２Ｓｉ。 Based on the results of microstructure observation of liquid quenched samples, the reaction kinetics of SiO2 and MgLi alloy melt was analyzed. The kinetic model of reaction between SiO2 and MgLi melt was established, and the control measures of particle size and its distribution in melt were proposed. The velocity expression of reaction between SiO2 and MgLi melt was obtained, and the formation position of Mg2Si was determined. The results show that the reaction between SiO2 and MgLi alloy melts is carried out in two steps, that is, the reaction of MgO and Si first occurs at the interface, and then Si reacts with Mg to form Mg2Si.