Abstract:Phase equilibria in the Zr-rich region of Zr-Fe-Si system at 580 ℃ was determined through equilibrated alloy method by using X-ray powder diffraction (XRD), scanning electron microscope (SEM) and energy dispersive x-ray analysis (EDX). Five two-phase equilibria Zr2Si + Zr2Fe, Zr2Fe + ZrFe2, Zr2Fe + Zr3Fe, Zr2Si + Zr5Si3, α-Zr + Zr2Si and two three-phase equilibria α-Zr + Zr2Fe + Zr3Fe, α-Zr + Zr2Si + Zr5Si3 were included in this study. The compounds Zr2Fe and Zr5Si3 which were marked as unstable phases at 580 ℃ in the available Zr-Fe and Zr-Si phase diagrams were observed, While the compound Zr3Si which was marked as stable phase in the Zr-Si phase diagram was not observed in this work.. It was shown that Zr2Fe and Zr2Si with same crystal structure were partially miscible. Solubility of Fe in Zr2Si is up to 5.95 at.% and solubility of Si in Zr2Fe is up to 6.38 at.%. ZrFe2 (cubic crystal structure) dissolves 3.11 at.% of Si.