Combining micro-textures and nanofluid electroosmotic flow for improving wear resistance of Si3N4 ceramic tools in machining of nickel-based superalloys

Abstract

To address the challenge of insufficient penetration performance of cutting fluids at the tool-chip interface in Si₃N₄ ceramic tool machining of nickel-based superalloys, which leads to inadequate cooling/lubrication efficiency and consequently rapid tool wear and machining damage, this study proposes a novel cooling/lubrication method combining micro-textured tools with nanofluid electroosmotic flow under self-excited electric field assistance. This approach enhances efficient nanofluid penetration and lubrication at the micro-textured Si₃N₄ tool-chip interface. Initially, numerical simulations were conducted to analyze the flow and heat transfer characteristics of nanofluids in micro-textured channels under self-excited electric fields. A comprehensive electroosmotic flow and heat transfer model was established based on principles of electrostatics, thermodynamics, and fluid dynamics. The results demonstrated that increased electric field intensity enhanced both the electroosmotic force and flow velocity of nanofluids within micro-textured channels. Subsequent cutting experiments on GH4169 nickel-based superalloy investigated the effects of nanofluids with distinct electrical properties on the cutting performance of Si₃N₄ ceramic tools under self-induced electric fields. Experimental data revealed that the textured Si₃N₄ tools (TSN) lubricated with SiO₂ nanofluid (SSNF) exhibited optimal cutting performance. At a cutting speed of 157.1 m/min, compared to the non-textured Si₃N₄ tool (SN) lubricated with traditional cutting fluid (TCF) and TSN tool lubricated with Fe₃O₄ nanofluid (SFNF), the cutting force was reduced by 32.71 % and 15.66 %, respectively, while cutting temperature decreased by 30.61 % (equivalent to a reduction of 150 °C) and 9.10 % (equivalent to a reduction of 34 °C). Additionally, surface roughness was reduced by 56.52 % and 15.79 %.