Phase Equilibria in the Fe-Mo-Co System: Experimental Investigation and Thermodynamic Calculation

Abstract

As a kind of high-performance tool material, the phase relationship and microstructure evolution of Fe-Mo-Co alloy during manufacturing processes deserve attention and study. In the present work, isothermal sections of the Fe-Mo-Co system at 800 and 1350 °C were investigated using the equilibrium alloy method and diffusion couple technology. No ternary compounds were found in either isothermal section. Four three-phase regions and two three-phase regions were determined at 1350 and 800 °C, respectively. The μ-Fe7Mo6 phase presents a continuous solid solution in the two isothermal sections. A set of self-consistent thermodynamic parameters of the Fe-Mo-Co ternary system were obtained. The calculated results using the obtained thermodynamic parameters are in good agreement with the experimental results.