Towards understanding the drilling-induced subsurface damage mechanism of SiCp/Al composite based on microscale numerical modeling and experimental analysis

SiC particle reinforced aluminum matrix (SiCp/Al) composite is one of the key light metal matrix composites in the aerospace and electronics industries due to its outstanding material properties. However, the drilling-induced subsurface damage is crucial for its reliable application. This paper focuses on the subsurface damage mechanism (particle damage and crack damage) in the drilling of SiCp/Al composites based on microscale numerical modeling and experimental analysis. The proposed numerical model effectively simulates particle damage, including fracture and spalling. The crack formation and propagation mechanism are revealed. Specifically, stress concentration at the particle tip is the initial formation of the crack, and plastic deformation of the matrix material promotes the crack to extend to the subsurface, and eventually, the crack convergence damage is formed in combination with other cracks. The drilling-induced subsurface damage depth is determined based on microhardness tests, approximately 180–220 μm. The study provides a theoretical basis for the low damage machining of SiCp/Al composites.