An optimized calculation of phase diagram and thermodynamic properties of the NiCr system

Abstract

Optimised calculations of phase diagram (PD) and thermodynamic properties of the Ni-Cr system were carried out in [12]–[14] The incorrect topology of phase diagram was obtained in these works (the eutectic diagram with two points of the equal concentration for L/Fcc equilibrium). There are some new experimental data on the thermodynamic properties of liquid phase [10] and phase equilibriums Fcc/Bcc [11] for solid alloys of this system. A calculation of phase diagram of the Ni-Cr system with consideration of topology was carried out in [15], that provides a correct form of this diagram. But the optimized procedure of experimental data on the thermodynamic properties and phase equilibriums was not realised, and the last experimental data from [10]–[11] were not used. In this work the optimisation of the different experimental data on the thermodynamic properties (67 values) and phase equilibriums (also 67 values) from work [1] which was published in 1937 year to work [11] was conducted with using restrictions, obtained from correct topology of experimental phase diagram. The choice of models for liquid, Fec and Bcc phases was carried out among the polynomial class of models for the excess thermodynamic Gibbs potential. The autonomic programme was used for the optimised calculation and choosing of models.