Thermodynamic assessment of the Fe-Nb-Ti-C-N system

A self-consistent thermodynamic description for the Fe-Nb-Ti-C-N quinary system has been developed. Because many different descriptions were already available for, most of the sub-binary and ternary systems, a selection among several parameter sets had to be made. This was done for the Fe-Ti, Ti-C, and Ti-N systems considering experimental information on the Fe-Ti-C, Fe-Ti-N, and Al-Ti-C systems. Thermodynamic reassessments were carried out for the Fe-Nb and Nb-C systems looking at the Fe-Nb-C and Fe-Nb-N systems. Such selections or assessments were also made for the Nb-Ti, Nb-Ti-C, Nb-Ti-N, Nb-C-N, and Ti-C-N systems by looking at the experimental information on phase equilibria in the Fe-Nb-Ti-C-N system as well as corresponding binary and ternary systems. By this, a thermodynamic description for the Fe-Nb-Ti-C-N system could be obtained, which is applicable to thermodynamic calculations in microalloyed steels and hard-coating materials. The thermodynamic parameters and comparisons between calculation and experimental data are presented.