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采用第一性原理分子动力学研究1773 K下液态Mg?Si系的混合焓与结构序.通过计算转移电荷和差分电子密度,证实Si原子周围的化学环境由Si?Si相互作用所主导,由此决定混合焓在富Mg侧达到最小值.基于偏偶相关函数的HA键对分析结果显示,Si?Si原子对与Mg原子相吸引,且结构序随Si含量的演变可以描述为Si?Si原子对分散Mg原子以构成框架结构的过程.以局域Si原子构型的四面体序为研究对象,揭示混合焓与结构序之间的相关性,这能为理解液态Mg?Si二元系提供综合能量学与几何学的新视角.“,”The mixing enthalpies and structural order in liquid Mg?Si system were investigated via ab-initio molecular dynamics at 1773 K. By calculating the transferred charges and electron density differences, the dominance of Si?Si interactions in the chemical environments around Si was demonstrated, which determined that the mixing enthalpy reached the minimum on Mg-rich side. In terms of Honeycutt and Anderson (HA) bond pairs based on the partial pair correlation functions, the attraction between Si?Si pairs and Mg atoms was revealed, and the evolution of structural order with Si content was characterized as a process of constituting frame structures by Si?Si pairs that dispersed Mg atoms. Focusing on tetrahedral order of local Si-configurations, a correlation between the mixing enthalpy and structural order was uncovered ultimately, which provided a new perspective combining the energetics with geometry to understand the liquid Mg?Si binary system.