Stability of eutectic carbide in Fe-Cr-Mo-W-V-C alloy

The stability of the eutectic carbide in a self-designed Fe-Cr-Mo-W-V-C alloy during solidification was analyzed in this work. The carbide precipitation rule of the steel was calculated by Thermo-Calc. The typical microstructures at 1240 °C and 1200 °C were observed by optical microscope (OM), field emission scanning electron microscope (FESEM) and transmission electron microscope (TEM). The selected area diffraction patterns (SADPs) has been successfully used with TEM bright fields to identify the lattice structures of the carbides within a complex mixture of different types of carbides. The results show that the eutectic MC and M2C mix together along crystal grain boundary and exhibit the dendritic structure. The eutectic MC contains VC and WC, while the eutectic M2C contains V2C and Mo2C. The eutectic MC can exist stably and grows continuously, while the eutectic M2C disappears gradually.