Wheel type vibration magnetorheological compound polishing is capable of effectively enhancing the polishing efficiency of hard ceramic materials in the process of magnetorheological finishing. The abrasives start to move under the effect of periodically changing forces when non-resonant vibration is introduced. However, due to the random nature of the trajectory, it is challenging to conduct a quantitative analysis of the abrasive trajectory and accurately quantify the material removal amount of the abrasive. To quantify the impact of vibration on the material removal during the polishing of sintered silicon carbide ceramic, molecular dynamics simulation was used to reveal the influence of the change of the work mode of the force exerted by the magnetorheological polishing fluid to the abrasive on the length and removal amount of the abrasive. A quantitative method for measuring the scratch length of a single abrasive based on the principle of energy conversion was proposed. On the basis of this method, a material removal rate model was developed by combining rheological property analysis and abrasive wear theory. The average error between the theoretical and the actual value is 11.85 %. The validity is verified. This study provides a theoretical basis for exploring the internal mechanism of vibration in the polishing process.

Al-50Si is promising for electronic packaging and automotive lightweighting. However, Si particles cause cutting defects, reducing wear resistance. Thus, pulse laser remelting ultrasonic vibration composite cutting was developed. The key to effectively suppressing particle fracture and stress concentration, reducing surface roughness and subsurface damage, and enhancing wear resistance is to set the ultrasonic cutting depth based on the remelting layer thickness. When the laser pulse width is 120 ns, the power is 25 W, and the cutting depth is 40 mu m, the roughness decreases to 0.121 mu m.The residual stress drops to -9.6 MPa. The wear depth of the surface in the wear test is reduced to 4.43 mu m. The wear mechanism is abrasive wear. The wear resistance is significantly improved.

Al-50wt%Si finds extensive application in electronic packaging and space remote sensing, owing to its superior thermal and mechanical properties. However, uneven material removal during polishing leads to significant uneven removal between the two phases. A novel non-resonant vibration-assisted cluster magnetorheological polishing method is developed in this study to address the issue. By applying high-frequency, low-amplitude vibration, the activation and discharge of abrasive particles within magnetic clusters are enhanced, significantly improving material removal uniformity. Experimental and simulation results reveal that non-resonant vibration promotes abrasive migration to the polishing interface by destabilizing CIPs clusters. The behavior has elucidated through theoretical analysis. The synergistic action of the multi-field combination significantly enhances both the active abrasive particle count and impact efficiency. Under optimal conditions, this approach achieves a 52% reduction in the step height difference between the Al and Si phases, alongside a 32% decrease in surface roughness. This study establishes a fundamental framework for precision polishing of composites, demonstrating the critical role of vibration-magnetic field synergy in mitigating removal disparities and offering a new approach for efficient, low-damage composite polishing.

Si particle-reinforced aluminium matrix composite (Si/Al) is extensively utilized in various fields such as aerospace and electronic devices because of its excellent thermal conductivity and wear resistance. For Si/Al composite, a higher Si content generally leads to improved properties, including enhanced wear resistance and reduced thermal expansion. However, the large chunks of hard and brittle Si particles dispersed inside tend to fracture or be pulled out during machining, which can significantly compromise the overall machining performance. In this study, the 50wt% Si/Al composite was irradiated using a nanosecond pulsed laser, and the changes in the microstructure and mechanical properties were investigated through scratch, indentation, and wear experiments. The results demonstrate that the rapid heating and cooling characteristics of the pulsed laser effectively suppress reprecipitation of Si particles in the form of large blocks, thereby facilitating the formation of a modified layer with more uniform hardness in the 50wt% Si/Al composite. Furthermore, it was observed that the wear resistance of the modified composite surface was significantly improved, and that the brittle removal behavior of Si particles was markedly suppressed during the scratching process, resulting in a transition in the material removal mechanism from brittle-plastic coexistence to stable plastic removal. This study elucidates the mechanism underlying the nanosecond pulse laser modification assisted machining of 50wt% Si/Al composite, and provides a scientific basis for high-efficiency and low-damage machining of the material.

Al-50wt% Si alloy is widely used in aerospace, automotive, electronic packaging and other fields due to its excellent material properties. However, the presence of reinforced particle phase differing in hardness from the alloy matrix phase leads to significant tool wear during turning with PCD tools. Therefore, this paper proposes a pulsed laser assisted turning (PLAT) method combining pulsed laser with conventional turning, which has unique advantages in reducing PCD tool wear. The effects of laser power, pulse width and frequency on tool wear during PLAT were studied by comparative experiments. And the potential mechanism of PLAT to reduce tool wear was revealed by finite element simulation. The results shown that PLAT effectively reduces PCD tool wear compared with conventional turning (CT). The increase of laser pulse width will aggravate tool wear. While, the increase of laser pulse frequency will reduce tool wear. Temperature is the main factor affecting the wear form. The tool mainly experiences abrasive wear at low temperature. However, the predominant type of tool wear shifts to adhesion as the increasing temperature. At the same time, EDS analysis shows that the rise in temperature results in an elevation of the O element content within the wear region, which proves that temperature is also the decisive factor affecting oxidative wear. This study provides valuable insights into actual machining involving Al50wt% Si alloys and gives strategies for reducing PCD tool wear using PLAT.

The challenge of precisely controlling both macroscopic and microscopic damages to the Al matrix and twophase interface significantly impedes the large-scale utilization of SiCp/Al composites in aerospace and other domains. Pulsed laser ultrasonic vibration assisted cutting (PLUVAC) emerges as a highly promising approach. In comparison to conventional turning processes, PLUVAC reduces the surface roughness to 0.305 mu m. Moreover, the depth of subsurface damage is decreased by 49.2 %. However, the heat transfer process of pulsed laser and the microscopic action mechanism of the pulsed laser and ultrasonic to the workpiece surface and subsurface is unclear. Therefore, this paper uses micro and nano scale simulation methods. The temperature field and grain deformation process of PLUVAC were studied. It was found that PLUVAC inhibits work hardening and interface damage by promoting dynamic recovery. The formed subgrains are finer and more prone to recrystallization. Therefore, the crystal structure of PLUVAC tends to be more complete. This study provides a unique perspective for revealing the deep mechanism of PLUVAC improving the surface quality of ceramic particle reinforced metal matrix composites.

High silicon aluminum alloy has broad applications in high power packaging parts and automobile lightweight. However, hard and brittle Si particles make the alloy surface easily to break during machining, resulting in serious surface defects. In this paper, a pulsed laser surface remelting non-resonant vibration assisted grinding method was proposed. The advantages of high instantaneous energy and quick cooling rate of pulsed laser are applied to form a remelting layer. The machinability of the alloy is improved by refining Si particles. The periodic separation of the workpiece-tool is used to reduce grinding forces and tool wear when abrasive particles cut the modified layer with higher hardness. The influence of remelting of the alloy induced by different power pulse laser on the material mechanical properties was revealed by laser irradiation experiments and indentation experiments. The influence mechanism of pulsed laser on the crystal structure and element distribution was simulated by molecular dynamics. The validity of the grinding method was confirmed by characterizing the grinding force, residual stress, tool wear, surface roughness and surface defect. The surface roughness of Al-27 wt. %Si decreased to 26 nm under the condition of 20 W power, 2 mu m amplitude and 650 Hz frequency. The study reveals the deep mechanism of pulsed laser in laser assisted manufacturing and opens up a new research idea for the precise and low-damage processing of high silicon aluminum alloy.

High silicon aluminum alloy has attracted wide attention due to its excellent performance. However, the processing difficulty greatly limits the application scope of the material. In this paper, the surface modification mechanism of high silicon aluminum alloy at different laser energy densities was investigated by molecular dynamics simulations. The results show that the increase of the laser energy density leads to the weakening of the interatomic bonding force of the material, which results in a significant reduction of the grinding force. Compared to conventional grinding, the average tangential and normal forces decreased by 57.9 % and 86.6 % when the laser energy density is 200 eV/ps. The depth of the high shear strain region varies nonlinearly with the increase of laser energy density, which indicates the dynamic competition between mechanical stresses and thermal effects in the machining process. With the increase of laser energy density, the transformation rate of Al matrix to amorphous and hexagonal close-packed structures accelerated, the number of transformed atoms increased, and the hindering effect of Si particles on the abrasive was also weakened. Compared with conventional grinding, the dislocations, stacking faults, and twin boundary density are significantly reduced in laser- assisted grinding. This is mainly attributed to the laser thermal effect, which promotes the dynamic recrystallization, defect annihilation, and atomic rearrangement processes. Additionally, the laser heating effect enhances the interaction between dislocations, crystal planar defects, and Si particles, promoting dynamic recrystallization and the annihilation of defects. This paper provides a comprehensive understanding of the defect evolution mechanisms during laser-assisted grinding and establishes a theoretical basis for optimizing machining parameters.

The utilisation of aluminium-based silicon carbide composites (SiCp/Al) is on the rise. However, during the grinding process, where abrasive particles compel SiC particles into the aluminium matrix, stress concentration occurs near the interface between the two phases. This phenomenon results in adverse surface deformation accompanied by residual compressive stress (RCS). Consequently, a pulsed laser-ultrasonic-assisted grinding method (PL-UAG) has been proposed. The effectiveness of the method is verified through grinding experiments. Moreover, the influence process of the thermal effect of pulsed laser and the evolution mechanism of microscopic RS near the SiCp/Al two-phase interface are revealed through molecular dynamics simulation. The experimental results show that the surface RCS of SiCp/Al gradually decreases and transforms into residual tensile stress (RTS) with the increase of laser power. The RCS increases with the grinding depth. The RCS is reduced to 17 Mpa and the surface roughness Sa value is reduced to 0.110 μm with the laser power is 40 W and the grinding depth is 1 μm. The simulation results show that the energy dissipation process of pulsed laser helps to reduce thermal deformation and damage. The laser-induced thermal effect reduces the deformation of the aluminium matrix caused by particle extrusion and inhibits the formation and slip of dislocations in the aluminium matrix. In addition, the ultrasonic shock effect effectively weakens the RTS generated by the laser.

The problems of low polishing efficiency and serious surface damage in the processing of silicon carbide (SiC) ceramics are well-known. In view of the above problems, a new method of photocatalytic vibration composite polishing (PVCP) combined with a compound control strategy was proposed. A vibration-assisted device was developed, and a compound control system was designed for the device to improve the trajectory tracking accuracy. Experiments were carried out to verify the effectiveness of the vibration-assisted device and the compound control system. In addition, methyl orange degradation and fading experiments, redox potential measurement experiments, and SiC ceramic surface hardness characterization experiments were carried out to reveal the effects of vibration and photocatalytic parameters on polishing solution oxidation and SiC ceramic surface mechanical properties. Finally, the effects of photocatalysis, vibration frequency, amplitude, and the compound control system on the polishing effect were analyzed. The results show that when the UV intensity is 100%, the polishing force is 3-4N, the vibration frequency is 400 Hz, the amplitude is 15 mu m, and the surface roughness of SiC ceramics is reduced by about 11 nm after the introduction of the compound control system, which verifies the effectiveness of the combination of the compound control system and PVCP.

Based on the technological characteristics of roll-type polishing, a new asymmetric vibration-assisted stage is proposed in this paper. This stage is characterized by asymmetric displacement and asymmetric stiffness. With the average particle spacing of roll-type polishing as the constraint, the comprehensive characteristics of structural stiffness, kinematic range, and natural frequency are realized. Thus, to reduce the surface roughness, the removal of simple-directional surface textures generated by roll-type polishing can be achieved. First, the asymmetric structure is designed, modeled, and optimized according to working performance design goals of roll-type polishing. Then, the finite element analysis and actual performance test of the stage are carried out to verify the accuracy of the established model and the effectiveness of the optimization design. The results indicate that the stage can meet the design index. Finally, the asymmetric vibration-assisted polishing experiment is carried out. The results show that the single-directional surface textures of the SiC surface are interrupted and the surface roughness is decreased.

With the aim of improving the performance of diffraction gratings, a piezoelectric-driven vibration-assisted UV nanoimprint method is proposed for use in the fabrication of diffraction gratings. It is found that by introducing one-dimensional lateral vibrations with a low-frequency and a low-amplitude into nanoimprinting, the surface quality of the resultant grating is improved and the filling rate of the photoresist in the mold is enhanced. The influence of the grating properties on the diffraction efficiency was determined via a simulation analysis, and the effects of the vibration frequency and vibration amplitude on the filling rate were studied; via these studies, a series of parameters describing the imposed vibrations that are expected to be suitable for use in the vibration-assisted UV nanoimprinting method is obtained. Furthermore, a novel asymmetric vibration stage is designed. The performance of the vibration-assisted UV nanoimprinting method was verified via scanning electron microscopy. Under the illumination of a light source, the measured diffraction angle is consistent with that predicted using the diffraction equation. The results indicate that vibration-assisted UV nanoimprinting method can accurately fabricate diffraction grating structures with superior performance compared with gratings obtained via other methods.

Magnetorheological finishing (MRF) is an important technique to achieve the surface precision of difficult-to-cut materials. In this paper, a wheel-type vibration-magnetorheological compound finishing is proposed in terms of reducing the unidirectional scratch caused by the wheel-type magnetorheological finishing tool and further improving the convergence rate of surface roughness. The vibration-magnetorheological coupling was realized through utilizing designed magnetorheological finishing (MRF) wheel and a nonresonant vibrational device (NRVD). Through the theoretical and experimental analysis, the surface roughness has been verified improved through increasing the normal and tangential forces, which are associated with introducing 2D vibration. The flow and viscoelastic models of the MRP fluid were established based on hydrodynamic lubrication and viscoelasticity theories. Finally, the feasibility of the proposed finishing method was verified by the results of improving surface roughness through designing reasonable processing experiment.

Nano-finishing of material surfaces is an important class of technology in precision manufacturing. This paper presents a non-resonant vibration-assisted magnetorheological finishing method for difficult-to-process materials. The aim is to enhance the shearing effects of the magnetorheological finishing. A two-dimensional vibration-assisted polishing device was developed, and the impact forces generated by the vibration could change the contact force during the experiments. A polishing force model that considered the vibration parameters was established, which could analyze the processing principles and explain the reason for the increase in shear force. Then, a set of processing experiments were carried out to study the effects of vibration parameters on the surface roughness and peak-to-valley value of silicon carbide samples. Finally, the relationship between the vibration parameters, surface quality, and polishing forces was studied. Theoretical calculations and experimental analyses show that the vibration could improve the shearing effects of the flexible polishing cluster. Meanwhile, a higher amplitude and frequency could raise the total shear force, which can lead to a better surface quality.

Fast tool servo (FTS) machining technology is a promising method for freeform surfaces and machining micro-nanostructure surfaces. However, limited degrees of freedom (DOF) is an inherent drawback of existing FTS technologies. In this paper, a piezo-actuated serial structure FTS system is developed to obtain translational motions along with z and x-axis directions for ultra-precision machining. In addition, the principle of the developed 2-DOF FTS is introduced and explained. A high-rigidity four-bar (HRFB) mechanism is proposed to produce motion along the z-axis direction. Additionally, through a micro-rotation motion around flexible bearing hinges (FBHs), bi-directional motions along the x-axis direction can be produced. The kinematics of the mechanism are described using a matrix-based compliance modeling (MCM) method, and then the static analysis and dynamic analysis are performed using finite element analysis (FEA). Testing experiments were conducted to investigate the actual performance of the developed system. The results show that low coupling, proper travel, and high natural frequency are obtained. Finally, a sinusoidal wavy surface is uniformly generated by the mechanism developed to demonstrate the effectiveness of the FTS system.