Microstructures and wear resistance of large WC particles reinforced surface metal matrix composites produced by plasma melt injection

Large WC particles (-840 mu m-+420 mu m) reinforced surface metal matrix composites (SMMCs) were produced using plasma melt injection (PMI) process on a Q235 (similar to ASTM A570 Gr. A) low carbon steel substrate. Microstructures of the SMMC were observed using scanning electron microscope (SEM), and the composition was determined with energy dispersion spectroscopy (EDS). Phases were analyzed with X-ray diffraction. Micro-hardness of the SMMC was tested. Wear losses of the SMMC layer were evaluated under dry friction conditions and compared with those of the substrate material. The results show that the large WC particles are caught by crystallized metal and stay in the upper part of the SMMC layer, and there is only a little melting on the outer surface. No sinking down of WC particles occurs. The SMMC layer is well bonded to the substrate, and the interface is crack free. The wear resistance of the Q235 substrate is greatly improved with large WC particles injected. (C) 2007 Elsevier B.V. All rights reserved.