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Powder-mixed electro-discharge machining (PMEDM); Inconel 718; superalloy; multi-walled carbon nanotubes (MWCNTs); surface integrity

The present work reports an experimental investigation on Powder-Mixed Electro-Discharge Machining (PMEDM) of Inconel 718 superalloy using Multi-Walled Carbon Nanotubes (MWCNTs) dispersed in kerosene, as dielectric media. Effects of variation of peak discharge current along with concentration of carbon nanotubes in the dielectric fluid are studied in purview of machining performance indicators including material removal efficiency, tool wear rate, and surface integrity of the machined part. The obtained results are compared to that of conventional EDM which utilizes kerosene as dielectric media. Morphology and topography, these two aspects of machined surface integrity are deliberated. The following surface morphological features: uneven fusion structure, globules of debris, molten metal deposition, surface cracks, pockmarks, and recast layer are identified. Topographical study includes surface roughness, severity of surface cracking, recast layer thickness, transfer of foreign elements, surface metallurgical characteristics, residual stress, and microindentationhardness. It is observed that application of MWCNT mixed dielectric media substantially improves EDM performance of Inconel 718 over conventional EDM. This is due to excellent thermo-physical properties of carbon nanotubes.

THRINADH JADAM¹ SANTOSH KUMAR SAHU² SAURAV DATTA¹ MANOJ MASANTA¹

1. Department of Mechanical Engineering, National Institute of Technology, Rourkela, Odisha 769008, India
2. Department of Mechanical Engineering, Veer Surendra Sai University of Technology (VSSUT), Burla, Sambalpur, Odisha 768018, India

Published

23 May 2020

Manuscript received

25 March 2019

Manuscript revised

11 October 2019

Accepted

21 April 2020