An experimental investigation of liquidus and solidus projections for the Fe–Mn–Ce system

Abstract

Phase equilibria in the Fe–Mn–Ce system were studied using DTA, X-ray diffraction, SEM and electron probe microanalysis. Liquidus and solidus projections for this system over the whole concentration range were constructed. The ternary compounds Fe11Mn6Ce2 (τ1) (Th2Ni17–type) and Fe5Mn7Ce (τ2) (ThMn12–type) solidify incongruently by peritectic reaction L + (γFe,Mn) + (Fe2Ce) ⇄ τ1 and L + (γFe,Mn) + τ1 ⇄ τ2 at 974 and 953 °C, respectively. These ternary compounds are located along lines of constant Ce concentration of 10.5 and 8 at.% Ce, respectively, and have significant homogeneity ranges. The homogeneity range of the τ1–phase extends from 20 to 36 at.% Mn. The homogeneity range of the τ2–phase extends from 35 to 78 at.% Mn. The solubilities of Mn in Fe17Ce2 and Fe2Ce were established to be 18 and 33 at.%, respectively.