THERMODYNAMIC SOLUTION MODEL OF DILUTE BI NARY-SYSTEMS PART I - ACTIVITY-COEFFICIENTS OF SOLUTE ELEMENTS IN SOLID-PHASE IN CR, MO AND W BASE DILUTE ALLOYS

The presented paper proposes an extension of the thermodynamic solutio n model by Tanaka et al. which enables us to predict the activity coef ficients of solute elements for infinite dilution in solid phase. This method integrates the calculation of partial enthalpy of mixing by Mi edema's semi-empirical method and Gokcen's first approximation of regu lar solutions. The activity coefficients of various solute elements we re calculated in solid phase of Cr, Mo, and W base dilute alloys at th eir melting point.