Microscopic study of Al–SiC particulate composites processed by laser shocks

Coatings of composite Al+50 wt% SiC were initially deposited using the high velocity oxy-fuel (HVOF) technique and subsequently submitted to shocks generated by a Nd:glass laser. The as-sprayed and laser-treated samples of the coatings were analyzed with an optical microscope (OM) and a transmission electron microscope (TEM). The OM study evidenced the improvement of the contact between the aluminum matrix and SiC reinforcement in the laser shock-treated samples. TEM investigations enabled us to find a high concentration of linear defects at the surface of the samples. These defects, indicating the plastic deformation of the aluminum matrix, are related to the poor performance of laser-treated composites in the sliding wear tests.