Modification and verification of Miedema model for predicating thermodynamic properties of binary precipitates in multi-element alloys

At present, there is still a certain difference between the calculated and experimental results of the original Miedema formation enthalpy model. Therefore, it is necessary to improve the calculation accuracy of the Miedema model to facilitate the development of the Miedema model and its application in alloy design. To address the problem, a new atomic size factor is introduced to modify the Miedema model in this paper. Then, the accuracy of the modified Miedema model is verified. Firstly, the formation enthalpies of various magnesium-based binary alloys are recalculated using the modified Miedema model. Secondly, the precipitation temperature of MgZn phase in Mg–6Zn-0.6Zr ternary alloy is predicted using the modified Miedema model combined with Chou model, which is compared with the experimental result. Thirdly, the precipitation of binary phases in Mg–Zn–Zr–Y quaternary alloy is analyzed by calculation based on the modified Miedema model. The final results show that the calculated results obtained from the modified Miedema model are in good agreement with the reported results, experimental results and phase diagram results, indicating that the modification is reasonable.