Experimental study of the phase relations in the Fe–Cr–Si ternary system at 700°C

Abstract The 700°C isothermal section of the Fe–Cr–Si ternary phase diagram has been determined experimentally by means of scanning electron microscopy coupled with energy dispersive X-ray spectroscopy and X-ray powder diffraction. Ten three-phase regions exist in the 700°C isothermal section. The binary σ phase contains 0–17.6 at.% Si and 31.4–59.2 at.% Cr; the Fe 5 Si 3 phase is stable at 700°C because of the dissolution of Cr. At this temperature, Fe and Cr cannot be entirely substituted by each other to form the FeSi or CrSi phases: the maximum possible Cr content in FeSi 2 , Fe 5 Si 3 and D0 3 is 3.9, 20.7 and 15.2 at.%, respectively, and the maximum soluble Fe in CrSi 2 , Cr 5 Si 3 and Cr 3 Si is 2.5, 20.4 and 16.8 at.%, respectively.