Shear thickening polishing technology using non-Newtonian polishing uid is a low-cost, low-damage polishing method for the ultra-precision machining of complex curved surfaces. However, the shortcomings of traditional shear thickening polishing uid in polishing e ciency and uid viscosity controllability limit its further application., a novel weak magnetic eld-assisted shear thickening polishing uid (WMFA-STPF) containing carbonyl iron particles (CIPs) is presented in this study, which utilizes its weak magnetorheological effect to strengthen the shear thickening phenomenon. The rheological characteristics of the WMFA-STPF samples were investigated. The results show that WMFA-STPF has good uidity in the low shear rate range and better thickening characteristics in the working shear rate range. In order to verify the high e ciency, high quality and high uniformity polishing ability of the weak magnetic eld-assisted shear thickening polishing technology for the spherical surface of zirconia ceramic workpiece, the contrast polishing experiment was designed and nished. The experimental results show that the weak magnetic eld-assisted thickening effect can achieve high e ciency and high quality polishing of hard and brittle ceramics. After 75 min polishing, the surface damage was effectively improved and eliminated, the surface quality and uniformity were greatly improved, and the material removal rate reached 7.82 μm/h, increased by 156%.

Ground white layer is caused primarily by grinding temperature induced phase transformation. So, it may form when grinding temperature exceeds the nominal phase transformation temperature. However, no attempt is made to investigate mechanical effect on formation of white layer. In this study, grinding temperature is measured by using thermocouple technique in grinding of AISI 52100 annealed steel. The specimens are investigated by using scanning electron microscope (SEM), energy disperse spectroscopy (EDS), micro hardness tester and X-ray diffraction (XRD). The microstructure and formation mechanism of white layer are analyzed. Ground whiter layer is confirmed to be composed of fine-grained cryptocrystalline martensite and retained austenite. High hardness of white layer is caused by transformation hardening through fine grain and high dislocation density due to severe deformation. White layer can form at temperatures below the nominal austenitization temperature of the material. Plastic deformation is also important in white layer formation during grinding process. High pressure on grinding surface exists under severe deformation. Phase temperature can be reduced due to high pressure; while crystal grain can be refined by plastic deformation. Oxidation and carburizing phenomenon exist during formation of white layer.

White layers formed in grinding process have negative effects on components. White layer will result in brittle surfaces, which will cause product failure. Since grinding parameters may influence white layer formation, it is necessary to study the relationship between white layer thickness and various grinding parameters. In this study, grinding experiments are carried out using harden AISI52100 steel as work material. Grinding parameters，such as wheel speed, workpiece speed, grinding depth, grinding wheel wear and cooling condition on the thickness of white layer have been studied. The specimens were analyzed using a micro hardness tester and SEM. The experiments indicate white layer depth varies with the different combinations of machining parameters. The depth of white layer increases with the grinding depth, wheel speed and wheel wear. There is a critical work table

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The centrifugal force has great influence on characteristics of the turbine shaft. The changes of stress, diameter and natural frequency of the turbine shaft for self-developed micro-spindle for micro-cutting following with the rotational speed were studied by finite element (FE) simulation, which showed that stress, diameter of the turbine shaft and frequency of torsional vibration in elastic shaft coupling integrated with the turbine shaft caused by the centrifugal force increases almost linearly with increase of rotational speed and the higher the speed, the larger the increase. The frequencies of other vibrational modes were influenced by centrifugal force. Materials with good properties can improve characteristics of turbine shaft caused by the centrifugal force well.