WCp/Fe metal matrix composites produced by laser melt injection

Laser melt injection (LMI) was used to produce WC particles (WCp) reinforced metal matrix composites (MMCs) layer on the mild steel. During the LMI process, different parameters were applied, and the processing window of this technique was obtained. The MMCs layers were studied by X-ray diffraction (XRD) and scanning electron microscopy (SEM). The SEM result reveals that none macro-defects except few pores can be found in the MMCs layer, and the WCp distribute uniformly in the layer. In addition, some new phases can be found in the MMCs layer, where Fe3W3C is the predominant phase. At the same time, the amount of dissolved WCp plays a key role in the microstructure of the MMCs layer. The WC particle dissolved into the melt pool leads to the appearance of reaction products in the matrix, such as various primary Fe3W3C dendrites, and the liquid WC remained on the solid WC particle results in the formation of a thicker reaction layer. (C) 2007 Elsevier B.V. All rights reserved.