Metal matrix composite production by means of laser dispersing of SiC and WC powder in Al alloy

The properties and processing parameters of the metal matrix composite (MMC) surface layers, obtained under conditions of the superposition of intense laser radiation with the kinetic effect due to gas-dynamically controlled particle injection, are investigated for the case of laser dispersing of the SiC and WC powders in the soft Al 6061 alloy. With substrate preheating above 600 K the nearly homogeneous distribution of SiC particles up to depths of about 1 mm, characterized by their content of about 35% by volume, is revealed by the scanning electron microscopes (SEM) inspection. In the microstructure the presence of the Al4C3 plates separated by the eutectic regions of Si-Al is observed and confirmed by the Xray diffraction (XRD) and energy-dispersive spectrometer (XEDS) measurements. The surface layers (25 cm(2)) consisting of parallel processing traces show the wear rate of about 3 x 10 (4) mm(3)/N m which is markedly lower than that of the reference substrate. For WC under similar processing conditions the particle enriched layer of thickness of about 100 mm is covered by the alloy material. The experimental data confirm that laser dispersing combines the advantages of the soft matrix with these of the wear and corrosion resistant material, and results in the improvement of the properties of composite material. (C) 2008 Elsevier B. V. All rights reserved.