Thermodynamic properties of molten LiMg alloy

The activity, the heat of mixing, the concentration fluctuation in the long wavelength limit (S_cc(0)) and the chemical short range order parameter (CSRO) have been studied as a function of composition in LiMg molten alloys by using first order quasi-chemical (QC) theory. The interchange energy has been considered a function of temperature and thus various thermodynamic quantities are calculated at elevated temperatures. The study reveals that though LiMg is considered a simple regular alloy, its various thermodynamic properties deviate from the ideal solution behaviour. S_cc(0) computed at different temperatures from QC-theory are found to be smaller than the ideal values and heterocoordination in the nearest neighbour shell is found to exist through the entire concentration range. On the other hand, S_cc(0) computed directly from the measured activity data indicates that the LiMg liquid alloy behaves as a segregating system for smaller content of Li (C_Li≤0.3). The building of heterocoordination starts around C_Li≥0.3 and remains for the rest of the compositions.