Mixing properties of Fe–Si alloys in liquid state based on linear temperature dependent energy parameters

A theoretical analysis of the thermodynamic, structural, and surface properties of liquid Fe–Si alloys has been conducted at various elevated temperatures using R–K polynomials. The thermodynamic parameters, including the free energy of mixing, heat of mixing, entropy of mixing, and activity of the components in Fe–Si alloys, were found to be in excellent agreement with the relevant experimental values. The structural behavior of the alloys indicates that the alloy has an ordering nature. Strongly ordered alloys produce more stable and homogeneous joints, which is desirable in welding. In addition, it was found that the surface tension of the alloy reduces as the temperature increases. The surface concentration of silicon was determined to be higher than the surface concentration of iron.