Tribology characteristics of WC/Fe composites by spark plasma sintering

The WC particles reinforced Fe matrix composites were fabricated by spark plasma sintering (SPS) with the WC particle mass friction of approximately 40%. The influence of sintering temperature on the density, micro-structure and mechanical properties of friction and wear properties of the WC/Fe composites were investigated. The phases of WC/Fe composites under different sintering temperatures were analyzed by XRD and SEM. The worn surface morphologeies of the two kinds of samples were observed by SEM and the wear mechanisms of samples were determined. The specific wear rates of the WC/Fe composites and matensitic wear-resistant steel were measured on a pin-disc tester (the counter face was a grade~80 μm Al₂O₃ abrasive paper). As the results, the complete densified WC/Fe composites can be obtained under 1080℃ and a homogenous distribution of WC particles within the Fe matrix with good interfacial bonding is obtained. The hardness and wear resistance of the WC/Fe composites increase gradually with the composites fully densification. The wear resistant performance of WC/Fe composites is far better than that of matensitic wear-resistant steel. The main wear mechanism of the matensitic wear-resistant steel is plough wear, and that of WC/Fe composites is oxidation wear and abrasive wear. Under low load condition, oxide film rupture is caused by particles break away from the substrate and lead to the worn surface; Under high load condition, brittle WC ceramics accelerate oxidation film broken, which lead to speed up the loss of WC/Fe composites.