ANALYSIS OF LIQUID-SOLID INTERFACE COMPOSITIONS OF Fe-Cr-Ni ALLOYS.

The liquidus and solidus surface compositions have been investigated in an Fe-Cr-Ni alloy in the Fe corner. The liquid-solid equilibrium compositions were measured by the stationary melting method, and the equilibrium distribution coefficient ratio was determined for the delta and gamma phases. These data, with the aid of a morphological analysis of the primary phase observed in unidirectionally solidified specimens, were used to determine the peritectic-eutectic line. The liquidus and solidus temperatures measured by D. T. A. were used to draw the liquidus and solidus surfaces. These data, combined with thermodynamical data of binary systems, were then used to fit the thermodynamic parameters in the Extended Regular Solution Model to provide the calculated liquidus and solidus surfaces.