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.