Enhancing Sustainable Machining of Inconel 718 Using Multi-Walled Carbon Nanotubes and TiO2based Nanofluid Minimum Quantity Lubrication

Abstract

Inconel 718 is extensively utilized especially in the aerospace sector due to its outstanding resistance to creep and corrosion, along with its capability to maintain strength at high temperatures. However, its high work hardening rate and low thermal conductivity present significant challenges in machining processes, including the need for extensive use of coolants, shortened tool life, and the necessity for post-processing operations for adequate surface quality, all of which hinder sustainable manufacturing. To address these issues, an innovative cooling/lubrication method, Nanofluid Minimum Quantity Lubrication (NMQL), aims to enhance the sustainable machining of Inconel 718 by minimizing these problems. NMQL involves the aerosolized delivery of nanoparticle-enriched nanofluid oil with compressed air to the cutting zone. In this way, NMQL utilizes the nanoparticles' cooling and lubrication abilities, resulting in lower cutting forces, reduced surface roughness, and decreased tool wear compared to other cooling/lubrication conditions, thereby improving machining performance. This study compares the performance of NMQL in terms of cutting forces, surface roughness and topography, and subsurface microhardness, using Multi-Walled Carbon Nanotubes (MWCNT) and TiO<inf>2</inf>nanoparticles, with Conventional Cutting Fluids (CCF), aiming to achieve more sustainable machining of Inconel 718. Also, a sustainability assessment was done using Pugh Matrix Approach in order to find the most sustainable cooling option. © 2025 Elsevier B.V., All rights reserved.