The present work is a continuation of research on alloys based on iron, with the aim to understanding the solidification behaviour of Fe-V-Nb alloys. Solidification sequences are proposed in relation to the observed microstructures for Fe-V-Nb synthesis alloys. Fe-V-Nb binary alloys with different concentrations are arc melted and characterized systematically by means of differential thermal analysis, optical and scanning electron microscopy coupled to an energy dispersive X-Ray microprobe analysis, quantitative XRF spectrometry and X-Ray diffraction. In the present work, the thermal and microsructural behavior of Fe–V –Nb alloys with different concentrations have been studied with the aim of answering some questions and especially paying attention to the microstructures and temperature transition. Two primary surfaces are identified: a(Fe) and Fe2Nb. Moreover, one invariant line is also identified as a binary eutectic reaction (L « a + Fe2Nb), which is clearly shown according to the observed microstructure. In perspective, other shades of this ternary alloy will be studied for a path projection of liquidus surface.