THE THERMODYNAMIC SOLUTION MODEL OF DILUT E BINARY-SYSTEMS - PART II - EQUILIBRIUM SEGREGATION COEFFICIENTS OF SOLUTE ELEMENTS IN CR, MO, AND W BASE DILUTE ALLOYS

The extension of the thermodynamic solution model of Tanaka et al. to solid binary systems enables us to calculate activity coefficients of solute elements in liquid and in solid phase in infinite dilution. The determination of both activity coefficients in liquid and in solid ph ase makes it possible to predict the equilibrium segregation coefficie nt of solute elements in transition metal base alloys without knowledg e of binary phase diagrams. The model was applied to Cr, Mo, and W bas e dilute alloys at the melting point of the base metal. The calculated values of equilibrium segregation coefficients are compared with thei r values determined by using of binary phase diagrams. The effect of i nput model parameters on the value of equilibrium segregation coeffici ents is discussed.