The influence of manufacturing-induced anisotropy on tool wear in drilling of Silicon carbide reinforced metal matrix composites

Materials with high specific strength, stiffness, and wear resistance are highly desirable in the aerospace and automotive industries. Among these materials, particulate-metal-matrix composites, which combine hard reinforcements such as silicon carbide with a metal matrix such as aluminum alloys, hold particular significance. Compared to monolithic alloys, these composites provide higher mechanical, thermal, and chemical properties. However, the inclusion of hard reinforcements significantly increases tool wear, impacting machining time, tool costs, and final surface quality. The objective of this thesis is to investigate the effect of manufacturing-induced anisotropy on the drilling of a metal matrix composite formed from an aluminum alloy matrix reinforced with silicon carbide particles. Due to the stir casting production method, the composite's internal and external regions have different silicon carbide rates. Drilling tests were conducted under specified conditions using tungsten carbide twist drill. The study examined the mechanical properties, thrust forces, adhesion, and tool wear in different regions of the metal matrix composite sample by comparing the pure aluminum sample. The results demonstrated that machining performance is significantly influenced by anisotropy, caused by the non-uniform distribution of silicon carbide resulting from the stir casting process. Regions with higher silicon carbide rate higher tool wear, adhesion, and thrust forces, while regions with a more uniform silicon carbide distribution exhibited improved machinability. Mechanical testing clarified that anisotropy also affects toughness, deformation, and tensile strength.