Effect of carbon on the phase formation in Fe85−xCr15Cx (x = 10–17) melts at low cooling rates

Abstract

The Fe-Cr-C alloys are promising hard facing materials with excellent wear resistance to address extreme technological environments which is provided by the presence of carbide chemical bonds stipulating high hardness. In this research, we study the influence of the carbon concentration from 10 to 17 at% on phase equilibria during heating, as well as crystallization processes of Fe-Cr-C alloys at 15 at% Cr and their relationship with the structure of the undercooled liquid state. The concentration dependence of undercoolability of Fe85−xCr15Cx (x = 10–17) melts revealed the minimum value in the region of the equilibrium eutectic near 14 at%C. Crystallization of Fe-Cr-C melts under cooling at a rate of 100 °C/min proceeds according to a nonequilibrium mechanism with the formation at the first stage of a solid solution based on fcc-Fe. Structure analysis of the undercooled Fe85−xCr15Cx melts (x = 10–17) showed that the nonequilibrium crystallization is related to peculiarities of interatomic interaction. Moreover, there is formation of structures with microhardness decreasing with growing carbon concentration in the alloy.