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Ultrasonic cavitation in nanofluids improves material removal rate and surface quality. Ultrasonic cavitation in nanofluids was investigated using molecular dynamics simulations. The formation and growth of nanobubbles were promoted, by nanoparticles in water systems. Three distinct impact stages were observed which were caused by the impact of the shock wave, nanojet and nanoparticle. These differed in the system without a nanoparticle. The material removal rate was primarily caused by the nanoparticle hit, a result of the nanobubble collapsing during the third impact. A mechanism of material removal in ultrasonic polishing is discussed at a nanometric level.

This work describes the experimental investigation of the residual stress distribution in the square pocket milling of 2219 aluminum alloy. The results reveal that the axial depth of cut is the most important factor influencing the residual stress distribution of the machined pocket surface, and the more tensile stress states are found with the increase in axial cutting depth due to the thermal deformation. The dominant mechanical deformation at all spindle speeds tends to produce the compressive residual stress. Altered feed rate and radial depth of cut show little changes in the residual stress distributions and the average values. In addition, the pattern of residual stress distribution of the square pocket surface is dramatically changed and the more tensile stresses are produced as the milling operation further proceeds. From this investigation, it is suggested to shorten the cutting time by raising the cutting parameters such as the feed rate and the radial depth of cut to achieve the compressive stress and the good surface roughness.

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This work performed molecular dynamic simulations to study the 2D profile and 3D surface topography in the nanometric cutting process. The least square mean method was used to model the evaluation criteria for the surface roughness at the nanometric scale. The result showed that the cutting speed was the most important factor influencing the spacing between the peaks, the sharpness of the peaks, and the randomness of the profile. The plastic deformation degree of the machined surface at the nanometric scale was significantly influenced by the cutting speed and depth of cut. The 2D and 3D surface roughness parameters exhibited a similar variation tendency, and the parameters Ra and Rq tended to increase gradually with an increase in the cutting speed and a decrease in the depth of cut. Finally, it is concluded that at the nanometric scale, the 3D surface roughness parameters could more accurately reflect the real surface characteristics than the 2D parameters.