Fe – V binary alloys with different vanadium concentrations (4 to 55 at.%) are arc melted and systematically characterized by means of; (1) differential thermal analysis, (2) optical and scanning electron microscopy coupled to an energy dispersive X-ray microprobe analysis, (3) quantitative X-ray fluorescence spectrometry, and (4) X-ray diffraction.The present work exhibits the solidification sequences according to the observed microstructures for Fe – V synthesis alloys. For the first time, a metastable -phase was observed in Fe rich alloy (4 at.% V). The phase transition is clearly shown. It takes place at 1320°C for the alloy V1 (4 at.% V).For higher vanadium contents (55 at.% V maximum), the -phase is no longer observable. The phase transition is also shown. The -phase precipitates directly by a congruent reaction from the -solid solution. It occurs at 1090°C for the alloy V3 (25 at.% V) and increases with the vanadium content (ranging from 25 to 55 at.% V). These results are plotted on the accepted Fe – V phase diagram.

C ast irons are used in industry due to their interesting mechanical properties and low manufacturing costs. Nevertheless, the performances of such alloys remain limited regarding some particular conditions of service (fatigue, abrasion, or corrosion). In fact, cracking occurs easily in graphite which causes mechanical failures, thereby reducing the mechanical resistance of the cast iron. Cast irons are widely used in applications involving resistance to abrasive wear. These parts can work under a wide variety of wear conditions, and the material structure can be modified to reinforce the friction properties. This structural modification can be obtained by localized quenching, or by superficial treatments [1] . Several studies have been conducted to investigate the effect of the alloying elements on the mechanical properties of gray cast irons [1][2][3][4][5] . It was found that aluminum could reduce quenching, refi ne the grains, give the graphite an inter-dendritic appearance,

The present work is a continuation of research on alloys based on iron, aiming at understanding the solidification behaviour of Fe-Cr-Nb alloys. Ternary Fe-Cr-Nb alloys with different concentrations were arcmelted and systematically characterized by means of; differential thermal analysis, optical and scanning electron microscopy coupled to an energy dispersive X-ray microprobe analysis and X-ray diffraction.For the first time, we suspect the presence of a metastable D'-phase in Fe-rich alloy. For higher vanadium and niobium contents a competition between two eutectics, E2 and E3, is clearly shown according to the observed microstructures and the solidification sequences.

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: (Fe) and Fe 2 Nb. Moreover, one invariant line is also identified as a binary eutectic reaction (L   + Fe 2 Nb), 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.

The boronizing kinetics of AISI 316L steel has been analyzed by employing five prediction models. The boron diffusion coefficients as well as the growth rate constants in the FeB and Fe2B phases were firstly evaluated in the range of 1123-1223 K. Afterwards, the values of boron activation energies in FeB and Fe2B were secondly deduced by adopting the Arrhenius relationships.In addition, the prediction models have been validated experimentally for two boronizing conditions (1170 K for 1.6 h and 1210 K for 1.1 h). The predicted results were deemed very concordant with the experiments. Furthermore, advantages and limitations about the applicability of these models were also discussed.