Impact of SiC Particle Incorporated Dielectric Medium on Machining Performance of AA7050/SiC/Al₂O₃ Hybrid Composites

Abstract

The component produced with best surface quality increases the life time of the product and with the objective of attaining it. AA7050 hybrid composites was processed using the electric discharge machining (EDM) technique. Composites with varying weight percentage of reinforced particles were manufactured using the stir casting technique. SiC and Al2O3 with an average particles size of 5 μm was used as reinforcement. EDM experimentation was conducted on the composites by varying pulse on time (Ton), current (A), powder concentration, and reinforcement weight percentage and the experimental runs were designed using Taguchi mixed orthogonal array, Material removal rate (MRR), tool wear rate (TWR), surface roughness (Ra), and machined surface hardness were recorded as response. When SiC particles were added into the dielectric fluid, MRR increased. The generated heat was uniformly spread throughout the machined surface due to the low thermal conductivity of SiC particles. TWR for composites machined with 2 wt% reinforcing materials increased significantly when powder particles were introduced, reaching 32.61 mg/min. The dispersed particles settled across the machined surface due to high density of SiC particles (4.36 g/cm3), lowering the surface quality. Black spots, remelted particles, globules, and micro pits are some of textures observed on machined surface morphology.