Simulation of the sulfide phase formation in a KhN60VT alloy

The conditions of the existence of sulfide phases in Fe–Ni–S alloys and four-component Fe–50 wt % Ni–0.001 wt % S– R ( R is an alloying or impurity element from the TCFE7 database) systems are studied using the Thermo-Calc software package and the TCFE7 database. The modification of nickel superalloys by calcium or magnesium is shown to increase their ductility due to partial desulfurization, the suppression of the formation of harmful sulfide phases, and the uniform formation of strong sulfides in the entire temperature range of metal solidification. The manufacturability of superalloys can decrease at a too high calcium or magnesium content because of the formation of intermetallics with a low melting temperature along grain boundaries.