The performance of SiAlON ceramics on drilling operations of carbon fiber reinforced polymer composites

Carbon fiber reinforced polymer (CFRP) composites are very promising materials in aerospace industry due to their high specific strength and outstanding fatigue resistance and their use in aerospace industry increases gradually. However, the abrasive character of the carbon fibers oriented in different directions in the composite makes these materials difficult to cut. Therefore, it is a prerequisite to develop high wear resistant cutting materials for machining of CFRP composites. In this thesis, it was aimed to determine the performance the SiAlON based materials, which are used in many wear applications due to their high mechanical, chemical and thermal properties, in drilling operation of CFRP composites. In this scope, besides the effect of drill bit geometry and machining parameters (cutting speed, v and feed rate, f) on the drilling process, the relationship between the wear resistance and the material properties of different SiAlON drill bits were investigated. It was observed that the micro-chipping is the main wear mechanism at early stage of the drilling operation. While the fracture toughness of the cutting material controls the wear of the drill bits at this stage, the abrasive wear, which becomes the dominant mechanism at further stages, is controlled by the hardness of the cutting material