Discussion On Forming Condition Of In-Situ VC Particles And Study In Corrosive And Abrasive Properties Of VC_p/Fe Composites

VC particles reinforced ferrous matrix composites were fabricated by in-situ reaction casting. According to thermodynamic result and phase diagram, properties and formation condition of VC particles were studied. The microstructure and tridimensional appearance were studied by XRD, SEM and EDX. The effect of melting parameters on the appearance of VC and mechanical properties of composite was also discussed. Estimative system was established to study the corrosion and wearing resistance of in-situ VCp/Fe composite compared with contrast-materials.According to thermodynamics result, Cr7C3 has the lowest Gibbs free energy in Fe-Cr-Ni-V-C smelting alloy system. It forms easily when the temperature below 1680℃. When the temperature surpasses 1680℃, Cr7C3 starts to decompose. VC particle forms rapidly at the same time, because VC has the lowest Gibbs free energy after decomposition of Cr7C3. The phase diagram of Fe-15Cr-V-C alloy shows that VC is formed firstly in the molten alloy in which the alloy is hypereutectic with the content of V and C is 8~10% and 2.4~3.0%. At the moment, VC has a fine spherical appearance, which distributes homogeneously in the matrix.Processing parameters including smelting temperature, reaction hour and nodularizer have obvious effects on the appearance of VC and mechanical properties of composite. VC particles are formed in large scale when the smelting temperature is above 1680℃. The content of Cr7C3 decreases with higher smelting temperature, which is helpful in increasing of toughness. The addition...