Microstructural and Mechanical Properties of In Situ WC-Fe/Fe Composites

In this study, Fe matrix reinforced with column-shaped WC-Fe composite was designed and fabricated by a novel in situ method. The WC-Fe/Fe composite exhibited a similar structure to that of reinforced concrete. The microstructure, microhardness, impact toughness, and wear resistance of the composites were characterized using scanning electron microscopy, and x-ray diffraction, as well as microhardness, impact, and wear tests. Small amounts of graphite (G), α-Fe, and WC were the predominant phases in the reinforcing bar of the composites. WC particulates improved the wear resistance of the composite, and the highest wear resistance was 96 times higher than that of gray cast iron under a load of 20 N with SiC abrasive particles. The wear resistance mechanism involved protection of the matrix behind the WC bundles by hard carbides. The excellent fracture toughness of the composite was mainly attributed to the disappearance of G flakes from the Fe matrix because of the in situ reaction, which reduced the split action to the matrix. The matrix absorbed a large amount of the crack propagation energy.