Influence of the Preliminary Heating of A7075 Aluminum Alloy on the Strength of a SiC-Containing Composite Coating

摘要

We created composite coatings on the surfaces of A7075 aluminum alloy by the method of laser melting of the substrate and injection of highly dispersed silicon-carbide (SiC) particles with additional preheating of the base metal and without it. The method of digital image correlation is adapted for the evaluation of the elastoplastic deformation of the material in different zones of the coating. The averaged values of local critical strains are obtained for the coated specimens under the conditions of static bending. It is shown that the preliminary heating of the substrate up to 100 degrees C weakly affects the deformability of the heat-affected zone as compared with heating up to 250 degrees C or without it. At the same time, we show that the fracture force and critical deflection of the specimens preheated to 100 degrees C become higher (almost by one-third) than for the specimens without heating. This can be explained by the formation of Al4C3 aluminum carbides on the boundaries of silicon carbide (SiC) particles.