A sub-regular solution model used to predict the component activities of quaternary systems

A sub-regular solution model used to predict the component activities in a homogeneous region of a quaternary system was developed in Shanghai Enhanced Lab of Ferrometallurgy. It was designated as SELF-SReM4. The component activities were described with the polynomials of the content variables, in which a group of Ajkl parameters involves. It was evaluated along with the reliable boundary conditions. The deduction of the model and the procedure of the evaluation of Ajkl parameters were introduced in detail in this paper.