Tribological characteristics and micromilling performance of nanoparticle enhanced water based cutting fluids in minimum quantity lubrication

Abstract

Friction and wear characteristics of water-based nanofluids were studied. Deionized water-based nanofluids were prepared with alumina (Al2O3), hBN, MoS2, and WS2 nanoparticles. Tribological study of the prepared nanofluids was undertaken on a ball-on-disk tribometer in minimum quantity lubrication (MQL) mode on Ti-6Al-4 V workpiece. The effect of flow rate on the coefficient of friction (μ) and wear of the workpiece was reported for different nanofluids. 3D profiles of the wear tracks were obtained to study the wear depth and wear profile. Alumina-based nanofluids have shown excellent performance in terms of friction and wear as compared to the other nanofluids. The coefficient of friction, wear track depth and specific wear were reduced by 53.89 %, 23.4 %, and 37.03 % respectively for alumina nanofluid in MQL mode as compared to the dry environment. A commercial cutting fluid (UNILUB 2032) was used for comparative studies. The commercial cutting fluid performed slightly better than the alumina nanofluid, both used in MQL mode. Even though hBN, MoS2, and WS2 are solid lubricants, their performance as nanofluids in MQL mode was not better than alumina nanofluids. Alumina particles, being spherical shaped, were able to provide better lubrication owing to the ball-bearing effect. Scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDS) of the wear tracks were conducted to understand the mechanism of friction and wear reduction. Micromilling experiments were done on Ti-6Al-4 V using the prepared cutting fluids in MQL mode to evaluate their effect on machining forces and burr formation. Alumina nanofluids and the commercial lubricant have shown significant reduction in machining forces and burr formation as compared to the other nanofluids. This is in correlation to the tribological performance of these cutting fluids.