Modeling and experimental study on tool-particle interaction and surface integrity in milling SiCp/Al metal matrix composites

High-efficient machining of SiC particles reinforced composites is always challenging mainly due to their poor surface integrity. In this study, a two-phase finite element model including the Al alloy matrix with Johnson-Cook model and SiC particle with elastic-brittle failure model were developed. The main purpose is to comprehensively investigate particle removal mechanisms and surface integrity following simulation and experimental studies on milling SiCp/Al composites. Specifically, the distributions of residual stress along the depth direction were predicted using finite element model. Results indicated that compressive residual stress mainly appeared on the machined surface, while tensile residual stress distributed at deeper depth down to 0.02 mm. Besides, different relative positions between tool and particle induced specific particle removal modes, which eventually led to various surface defects. Higher level of cutting speed (180 m/min) and feed rate (0.09 mm/tooth) aggravated surface defects and increased the thickness of broken-SiC layer in subsurface. The simulated machined surface defects and surface residual stress correlated well with the experimental observation, and the maximum error value of cutting force was less than 15%. The proposed finite element model was efficient to predict cutting force and distribution of residual stress along the depth direction.