Title: Bio-dielectric based eco-friendly electrical discharge machining of Ti6Al4V: assessment of the machined-surface morphology and micro-hardness

Authors: Shirsendu Das; Swarup Paul; Biswanath Doloi

Addresses: Mechanical Engineering Department, Techno College of Engineering Agartala, Tripura, 799004, India ' Production Engineering Department, National Institute of Technology Agartala, NIT Agartala, Barjala, Jirania, Agartala, Tripura, 799046, India ' Production Engineering Department, Jadavpur University Kolkata, Jadavpur, Kolkata, West Bengal, 700032, India

Abstract: This article aims to assess the impacts of the vegetable oil-based bio-dielectric (BD) mediums on the morphological features, recast layer, and micro-hardness of the processed surface. The analysis apparently disclosed the presence of fine cracks, surface inconsistencies, and migration of some flecks from the tool and dielectrics. Furthermore, some flurry holes are also detected on the surface, which are developed due to the clemency of trapped gases during the re-solidification process. The rapid periodic-discharge cycles of EDM cause abrupt discrepancies of temperatures and provokes residual stresses on the zones, which are already thermally influenced. It is observed that the cracks are comparatively shallow in the case of kerosene but much wider for bio dielectrics. The recast layer is 27-38% thinner, and the micro-harness of the recast and heat affected zone is 13.34% and 15% more with BD than those of the kerosene.

Keywords: EDM; bio-dielectric; BD; cracks; recast layer; surface-defects; textural defects; micro-hardness.

DOI: 10.1504/IJSURFSE.2023.135789

International Journal of Surface Science and Engineering, 2023 Vol.17 No.4, pp.339 - 357

Received: 11 Feb 2023
Accepted: 21 Apr 2023
Published online: 05 Jan 2024 *

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