Assessment of the surface characteristics of aerospace grade AA6092/17.5 SiCp-T6 composite processed through EDM

• Published in: CIRP journal of manufacturing science and technology 2021-05, Vol.33, p.123-132
• Main Authors: Das, Shirsendu, Acharya, Uttam, Rao, S.V.V.N. Siva, Paul, Swarup, Roy, Barnik Saha
• Format: Article
• Language: English
• Subjects: AMC; Cavities; Cracks; EDM; Flushing; Hardness; MRR; Roughness; Surface; Texture
• ISSN: 1755-5817; 1878-0016
• DOI: 10.1016/j.cirpj.2021.03.005

The recently developed composite ‘AA6092/17.5 SiCp-T6’ is gradually capturing the attention of the defense and aviation sectors, where various fabrication and material processing are required to accomplish. Considering this emerging demand, it may require to generate a few integrated shapes or micro-slots on this material. Therefore, the responses and textural features of the surfaces are analyzed here to evaluate the suitability of EDM-operation for future processing. Experiments are executed for various flushing velocities and three different discharge conditions and noticed an excellent response in all aspects. The machining rate increases with flushing velocity for low and medium discharge conditions but finally drops by 35–37.5% when the velocity is more than 10 m/s. However, the higher discharge energy can hold the machining rate up to a higher velocity level and the highest MRR of 29.27 mm3/min is obtained at 12 m/s flushing velocity. The textural features are mostly akin for low and medium discharges, and few solidified defects like indentation, flakes, thermal spots, cracks, etc., appear on the surface, which is absent for high discharge energies. The EDM-process ensures proper carbonation and heat-treatment to the surface, and a better hardness can be obtained with a higher current and low duty factor.