LAUSR

ABSTRACT Pb-Mg alloys have attracted attention in the metallurgical industry owing to their high electrode potential and lightweight characteristics. However, predicting their solid–liquid phase transition behaviour and component activity remains challenging. In this study, a modified embedded atom method (MEAM) combined with a molecular dynamics (MD) simulation is used to reveal the phase transition characteristics and microscopic mechanism of Pb-Mg alloys. The results show that the prediction deviations for the solid–liquid phase transition temperatures of Pb and Mg are less than 2%. The mixing enthalpy of Pb-Mg alloys shows significant negative deviations, which confirms that the strong interaction of the Pb-Mg atom pairs is dominant in the Pb-Mg liquid alloys. The change rule of the first coordination number in the phase transition process is obtained through analysis of the radial distribution function (RDF). This reveals the dynamic evolution of the degree of order of the system. The MEAM is extended to calculate the component activities of liquid alloys. The model based on the mixing enthalpy and Gibbs-Duhem equation can directly obtain the component activities without relying on experiments. The results provide a theoretical basis and data support for the optimisation of related alloy metallurgical processes.