Effect of machining parameters on surface properties in slide diamond burnishing of aluminium matrix composites

The implementation of light weight construction often requires the use of composites such as aluminium matrix composites. However, machining of suchlike materials is more difficult compared to unreinforced alloys. The heterogeneous structure of the metal matrix composites involves high tool wear and surface imperfections. For an increase of the fatigue strength, smooth surfaces and strongly compressive residual stresses in the surface layer are beneficial. The limits of cutting processes concerning surface properties can be overcome by using forming processes like slide diamond burnishing, which enables a highly efficient surface finishing of even thin-walled components. The effect of machining parameters and diamond sphere radius on surface properties are analysed. Experimental investigations in slide diamond burnishing of AA2124 with 25 % volume proportion of SiC particles show that surface roughness values and imperfections like voids can be reduced significantly. Furthermore, absolute values for residual stresses generated in the surface layer are in the order of the yield strength of the aluminium alloy. The application of slide diamond burnishing offers high potential for an increase of the tolerable load or a reduction of the mass of reliable components. (C) 2015 Published by Elsevier Ltd.