Reinforced SiC/Al composite layer produced by laser particle injection

SiC particles with a mean size of 80 mu m were injected into Al substrate:by the laser particle injection process with the aim to improve the surface properties of aluminium. Experimental difficulties induced by the big difference in absorptivity of laser energy between Al and SiC lead to an extremely small operational window of processing parameters.A combination of parameters of Nd:YAG laser beam, SiC powder stream and Al substrate pre-heating temperature which leads to the formation of single laser tracks was found experimentally. The injection depth is discussed from the point of view of a simple injection model.Optical, scanning and (high-resolution) transmission electron microscopy were used to study the microstructure of the produced particle reinforced metal matrix composite. Partial thermal decomposition of SiC and reaction with liquid Al lead to the formation of new phases presented in the laser tracks, detected as Al4C3 and elemental Si.