Shuaishuai Wang

Pure copper is an important metal material in the fields of integrated circuits, mold manufacturing, and aerospace. Its excellent ductility and plasticity lead to problems such as burrs and tool wear in cutting, which poses great challenges to the improvement of machining accuracy and surface quality. To achieve high-quality and efficient processing of pure copper, this paper proposes to use nanographene water-based lubricant (NGWL) to regulate its removal behavior. A single-grain diamond scribing test and a micro-milling test were carried out to systematically study the action mechanism of NGWL on removal behavior of pure copper. The results showed that, compared with dry scribing at normal forces of 100, 400, 700, and 1000 mN, the material removal efficiency induced by NGWL was increased by 54.1%, 80.7%, 44.8%, and 30.3%, respectively. Compared with dry micro-milling at feed speeds of 200, 600, 1000, and 1400 μm/s, for the 75°XT4E tool, the surface roughness Sa with NGWL-assisted micro-milling was reduced by 75.5%, 73.1%, 61.4%, and 44.2%, respectively. Similarly, for the 65°UDT4E tool, compared to dry micro-milling, the Sa with NGWL lubrication was also reduced by 28.9%, 52.2%, 54.4%, and 36.9%, respectively. The Sa of pure copper induced by NGWL could be as low as about 20 nm without scales. Overall, NGWL can regulate removal behavior of pure copper by alleviating plastic deformation and promoting ductile fracture, thereby providing a new approach to achieving high-quality and efficient processing of pure copper.

H-BN spherical nanoparticles, known as white graphene, have good anti-wear properties, long service life, chemical inertness, and stability, which provide superior lubricating performance as a solid additive item to nanofluids. However, the poor dispersion stability of h-BN nanoparticles in nanofluids is a bottleneck that restricts their application. Currently, to prepare h-BN nanofluids with good dispersion stability, a cold plasma (CP) modification of h-BN nanoparticles is proposed in this study. In this research, h-BN nanofluid with added surfactant (SNL), CP-modified h-BN nanofluid with N₂ as the working gas (CP(N₂)NL), and CP-modified h-BN nanofluid with O₂ as the working gas (CP(O₂)NL) were prepared, separately. The mechanism of the dispersion stability of CP-modified h-BN nanofluid was analyzed using X-ray photoelectron spectroscopy (XPS), and the performance of CP-modified nanofluid was analyzed based on static observation of nanofluid, kinematic viscosity, and heat transfer properties. Finally, friction and wear experiments were conducted to further analyze the tribological performance of h-BN nanofluids based on the coefficient of friction, 3D surface morphology, surface roughness (Sa), scratches, and micro-morphology. The results show that CP-modified h-BN nanofluid has excellent dispersed suspension stability and can be statically placed for more than 336 h. The CP-modified h-BN nanofluid showed stable friction-reducing, anti-wear, and heat transfer performance, in which the coefficient of friction of h-BN nanofluid was about 0.66 before and after 24 h of settling. The Sa value of the sample was reduced by 31.6–49.2% in comparison with pure cottonseed oil (CO).

Hastelloy is widely used in the manufacturing of high-temperature components in the aerospace industry because of its high strength and corrosion-resistant physical properties, as well as its ability to maintain excellent mechanical properties at high temperatures. However, with developments in science and technology, the amount of available components for use in high-temperature and corrosive environments is increasing, their structures are becoming more complex and varied, and requirements with regard to the surface quality of the components has also become more stringent. The integration of cold plasma (CP) and nano-lubricant minimum quantity lubrication (NMQL), within a multi-physics coupling-assisted micro-grinding process (CPNMQL), presents a promising strategy to overcome this bottleneck. In this paper, micro-grinding of Hastelloy C-276 was performed under dry, CP, NMQL, and CPNMQL conditions, respectively. Contact angle testing, X-ray photoelectron spectroscopy (XPS) analysis, and nano-scratch experiments were used to investigate the mechanism of CPNMQL and to compare the micro-milling performance under different cooling and lubrication conditions employing various characteristics such as grinding temperature, surface roughness, and 3D surface profile. The results showed that at different micro-grinding depths, the micro-grinding temperature and surface roughness were significantly reduced under CP, NMQL, and CPNMQL conditions compared to dry friction. Among them, CPNMQL showed the best performance, with 53.4% and 54.7% reductions in temperature and surface roughness, respectively, compared to the dry condition.

Carbon fibre-reinforced plastic (CFRP) composites, prized for their exceptional properties, often encounter surface quality issues during slotting due to their inherent heterogeneity. This paper tackles CFRP slotting challenges by employing multi-tooth mills in experiments with various fibre orientations and tool feed rates. In-plane scratching tests are performed under linearly varying loads; then, slotting experiments are conducted at different parameters. The scratching test results indicate that the fibre orientation and cutting angles have significant influences on forces and fracture process. The slotting experiments demonstrate that cutting forces and surface roughness S_a of the bottom slotting surface are notably affected by the fibre orientation, with disparities between up-milling and down-milling sides. Reorganising S_a data by local fibre cutting angle θ highlights consistent S_a variations between up-milling and down-milling sides for 0° ≤ θ ≤ 90°, with lower S_a on the up-milling side. However, for 90° < θ ≤ 150°, S_a variations diverge, with lower S_a on the down-milling side. Unexpectedly, S_a on the down-milling side decreases with increasing θ in this range. Additionally, the tool feed rate exerts a more pronounced influence on S_a on the up-milling side.

SCIEPublish is an international open-access journal publishing service provider run by SCIE Publishing Limited, dedicated to supporting and inspiring scientists or institutions/societies who aspire to publish high-quality journals.

SCIEPublish is an international open-access journal publishing service provider run by SCIE Publishing Limited, dedicated to supporting and inspiring scientists or institutions/societies who aspire to publish high-quality journals.