APPLICATION OF THE THERMODYNAMIC SOLUTION MODEL OF DILUTE BINARY-SYSTEMS II - EQUILIBRIUM SEGREGATION COEFFICIENT OF SOLUTE ELEMENTS IN INFINITE DILUTION

The thermodynamic solution model by Tanaka et al. for liquid binary sy stems was extended to solid binary systems. On the basis of this exten sion the activity coefficients of solute elements in the solid phase i n infinite dilution for transition metals were calculated in Part I of this paper. The determination of the activity coefficients in both so lid and liquid phases can enable one to predict the equilibrium segreg ation coefficient of the solute elements in transition metal base allo ys without the knowledge of equilibrium binary phase diagrams. The mod el was applied on Ti? Zr and Hf-base dilute alloys at their melting po ints. The calculated values of equilibrium segregation coefficients ar e compared with values derived by other methods. The effect of the mod el parameters on the value of equilibrium segregation coefficients was discussed.