Silicon carbide (SiC) ceramics are extensively utilized in aerospace, national defense, and petrochemical industries due to their superior physical and chemical properties. The processing of bulk SiC ceramics necessitates precise and efficient grinding techniques to produce components with satisfactory functionality. However, the inherent high hardness and brittleness of SiC ceramics present significant challenges during grinding, leading to severe brittle fracture and tool wear that compromise both surface integrity and production efficiency. Although ductile-regime grinding of SiC ceramics can be achieved by enhancing machine tool accuracy and stiffness while optimizing wheel performance alongside appropriate selection of process parameters, a comprehensive summary of the mechanisms underlying damage evolution during grinding is lacking, and a mature grinding process for SiC ceramics has yet to be developed. To bridge this gap, the sintering technologies, mechanical properties, and microstructures of SiC ceramics were briefly covered. The grinding-induced damage mechanism and low-damage grinding technologies of SiC ceramics were summarized. The fundamental science underlying the ductile deformation and removal mechanisms of brittle solids was emphasized. Additionally, attention was directed towards the critical role of hybrid energy field grinding in minimizing brittle damages and promoting removal efficiency. This review not only elucidates the intrinsic interactions between the work material and abrasives, but also offers valuable insights for optimizing the grinding processes of brittle solids.

Fluid lubricated bearings have been widely adopted as support components for high-end equipment in metrology, semiconductor devices, aviation, strategic defense, ultraprecision manufacturing, medical treatment, and power generation. In all these applications, the equipment must deliver extreme working performances such as ultraprecise movement, ultrahigh rotation speed, ultraheavy bearing loads, ultrahigh environmental temperatures, strong radiation resistance, and high vacuum operation, which have challenged the design and optimization of reliable fluid lubricated bearings. Breakthrough of any related bottlenecks will promote the development course of high-end equipment. To promote the advancement of high-end equipment, this paper reviews the design and optimization of fluid lubricated bearings operated at typical extreme working performances, targeting the realization of extreme working performances, current challenges and solutions, underlying deficiencies, and promising developmental directions. This paper can guide the selection of suitable fluid lubricated bearings and optimize their structures to meet their required working performances.

Fine finishing of tungsten alloy is required to improve the surface quality of molds and precision instruments. Nevertheless, it is difficult to obtain high-quality surfaces as a result of grain boundary steps attributed to differences in properties of two-phase microstructures. This paper presents a theoretical and experimental investigation on chemical mechanical polishing of W–Ni–Fe alloy. The mechanism of the boundary step generation is illustrated and a model of grain boundary step formation is proposed. The mechanism reveals the effects of mechanical and chemical actions in both surface roughness and material removal. The model was verified by the experiments and the results show that appropriately balancing the mechanical and chemical effects restrains the generation of boundary steps and leads to a fine surface quality with a high removal rate by citric acid-based slurry.

This study utilizes a dynamic mesh technology to investigate the dynamic performance of aerostatic thrust bearings with orifice restrictor, multiple restrictors, and porous restrictor. An experiment, which investigates the bearing static load capacity, was carried out to verify the calculation accuracy of dynamic mesh technology. Further, the impact of incentive amplitude, incentive frequency, axial eccentricity ratio, and non-flatness on the bearing dynamic performance was also studied. The results show incentive amplitude effect can be ignored at the condition of amplitude less than 5% film thickness, while the relationship between dynamic characteristics and incentive frequency presented a strong nonlinear relationship in the whole frequency range. The change law of dynamic stiffness and damping coefficient for porous restrictor was quite different from orifice restrictor and multiple restrictors. The bearing dynamic performance increased significantly with the growth of axial eccentricity ratio, and the surface non-flatness enhanced dynamic performance of aerostatic thrust bearings.

Many researchers concentrate on improving the stiffness and stability of aerostatic bearings, however the contradiction between stiffness and stability is still existed. Therefore, orifice, multiple, and porous restrictors are designed to illustrate the influence of restrictor characteristics on the stability and stiffness of the aerostatic circular pad bearings. Because both the stiffness and stability of aerostatic bearings are determined by the internal pressure distribution, the full Navier-Stokes (N-S) equations are applied to solve internal pressure distribution in bearing film by using computational fluid dynamics (CFD) method. Simulation results present that the stiffness and stability of aerostatic circular pad bearings are influenced significantly by geometrical and material parameters, such as film thickness, orifice diameters, and viscous resistance coefficient. Verified by the experimental data, the micro vibration of orifice restrictor is almost the same as multiple restrictors with amplitude of 0.02 m/s2, but it is much stronger than the porous restrictors with acceleration of 0.006 m/s2. The optimal stiffness of multiple restrictors increased by 46%, compared to only 30.2 N/μm of orifice restrictor, and the porous restrictors had obvious advantage in the small film thickness less than 6 μm where the optimal stiffness increased to 38.3 N/μm. The numerical and experimental results provide guidance for improving the stiffness and stability of aerostatic bearings.

Laser shock peening (LSP) is an advanced surface strengthening technique crucial for enhancing the performance of critical components operating in extreme service environments. By generating gradient residual compressive stress and refining the microstructure via the interaction between the laser and metallic materials, LSP achieves multiscale modulation of the surface properties of metal components and considerably improves the fatigue, wear, and corrosion resistance of the material under demanding conditions. Owing to its noncontact surface modification process and properties, LSP has garnered considerable interest across fields such as aerospace, rail transit, biomedicine, and the nuclear industry. The pulse duration of the laser used in LSP considerably influences its interaction with metallic materials. Ultrashort-pulsed LSP exhibits extreme nonlinear, nonequilibrium, and multiscale time/space properties during its interaction with metallic materials, distinguishing it from short-pulsed LSP. However, existing reviews have predominantly analyzed LSP based on various factors, equipment, single performance, and applications. The pulse duration, which inevitably influences the application of LSP, has not been investigated yet. This review analyzes about 180 short-pulsed LSP and approximately 100 ultrashort-pulsed LSP papers published between 1963 and 2025 and focuses on the laser pulse duration to elucidate the existing status and prospective application value of short- and ultrashort-pulsed LSP from the viewpoints of mechanisms, processes, and applications. The associated challenges and prospects are examined and summarized using strengthening mechanisms, high-fidelity prediction models, process coupling innovations, and intelligent and efficient strengthening equipment. This work offers valuable insights for advancing laser manufacturing processes towards meeting the rigorous demands of extreme applications.