China Foundry (May 2010)
Study on in-situ WC particles/tungsten wire reinforced iron matrix composites under electromagnetic field
Abstract
By applying electromagnetic field to a system consisting of tungsten wires and grey cast iron melt, the grey cast iron matrix composite reinforced by either in-situ WC particles or the combination of in-situ WC particles and the residual tungsten wire was obtained. By means of differential thermal analysis (DTA), the pouring temperature of iron melt was determined at 1,573 K. The microstructures of the composites were analyzed by using of X-ray diffraction (XRD), scanning electron microscopy (SEM) equipped with an energy dispersive spectrum (EDS) and pin-on-disc abrasive wear test. The obtained results indicated that, with the enhancing frequency of electromagnetic field, the amount of in-situ WC particles gradually increases, leading to continuous decrease of the residual tungsten wires. When the electromagnetic field frequency was up to 4 kHz, tungsten wires reacted completely with carbon atoms in grey cast iron melt, forming WC particals. The electromagnetic field appeared to accelerate the elemental diffusion in the melt, to help relatively quick formation of a series of small Fe-W-C ternary zones and to improve the kinetic condition of in-situ WC fabrication. As compared with the composite prepared without the electromagnetic field, the composite fabricated at 4 kHz presented good wear resistance.
