Microstructure Characterization and Performance Evaluation on AA7075 Metal Matrix Composites Using RSM Technique

Ceramic particles-reinforced casted aluminium matrix composites are extensively used in aircraft and in the manufacturing of automobile components due to its excellent properties such as light weight, high strength and increased hardness. In this present research work, conventional liquid metallurgy method has been adopted to fabricate the AA7075/BN-reinforced metal matrix composites. The boron nitride ceramic powder is added with different wt% such as (0, 4 & 8). The distribution of reinforcement particles in the matrix material is identified through scanning electron microscopy. Drilling experiments are performed on fabricated composites through vertical CNC drilling machine using fully carbide drill bit and by modifying the process parameters such as spindle speed, feed and point of angle. Subsequently by varying the cutting tool angle (118°, 108° & 98°), drilling experiment is conducted. Mill tool dynamometer is used to find out the thrust force while drilling. Response surface methodology is used to optimize the output responses of thrust force and surface roughness effects from drilled metal matrix composites. The setting of experimental parameters is made with L₂₇ Box–Behnken design factors and is performed with four factor three level. This investigation has shown that feed and point of angle are major influencing factors affecting the thrust force and surface roughness. Also, the tool wear, chip morphology and hardness of the fabricated composite material were examined.