The Cr–Fe–Nb ternary system: Experimental isothermal sections at 700 °C, 1050 °C and 1350 °C

•Determination of Phase Equilibria in the Cr–Fe–Nb system at 700, 1050 and 1350 °C.•Isothermal sections at 700, 1050 and 1350 °C were established.•Homogeneity range of Laves phases were determined.•Solubility of Fe and Cr and lattice parameter evolution in the ternary phases were determined.

The Cr–Fe–Nb system is an important constituent system in the development of Laves-phase reinforced steels. It contains two Laves-phase polytypes, i.e. C14–Fe2Nb and C15–Cr2Nb. While the first forms a substantial ternary solid solution with Cr, the latter only shows a limited solubility for Fe. The phase equilibria in the Cr–Fe–Nb system are shown in three isothermal sections at 700, 1050 and 1350 °C. Scanning electron microscopy coupled with energy dispersive X-ray analysis (SEM/EDX), X-ray diffraction (XRD) and electron back scatter diffraction (EBSD) were used to determine the phase equilibria from which the isothermal sections were constructed.