Research On Key Technologies Of Vibration-Assisted Magnetorheological Finishing Of Metal Matrix Composite Materials

Metal matrix composites are widely used in high-tech fields such as aerospace,electronic packaging,and precision optical instruments because of their excellent mechanical properties such as high specific strength,high specific stiffness,and low coefficient of thermal expansion.However,due to the difference in hardness between the matrix and reinforced phases in metal matrix composites,a "step effect" can occur during conventional processing,preventing a high-quality surface.This paper combines the advantages of magnetorheological finishing and vibration processing technologies and proposes a non-resonant vibration-assisted magnetorheological finishing(NVMRF)method to improve the machinability of a typical metal matrix composite,aluminumbased silicon carbide(SiCp/Al).The main focus of the theoretical and experimental research is on the design and performance testing of NVMRF devices,the mechanism of SiCp/Al material removal,and the rapid improvement of polished surface quality.The research provides a new approach to the efficient processing of SiCp/Al.The main contents and results are as follows:(1)Design and performance testing of the vibration device.Based on the processing characteristics of NVMRF and using flexible mechanism theory,the vibration device is designed with high frequency and large amplitude as the design target,and its theoretical model is established;finite element analysis is used to simulate the stiffness,stress,and mode of the vibration device to verify the accuracy of the model;The performance of the vibration device in terms of natural frequency,stroke,and resolution is tested online to provide an equipment basis for subsequent experimental studies.(2)Research on the removal mechanism of NVMRF materials.Based on nanoindentation experiments,the microscopic mechanical properties of SiCp/Al are tested and the indentation deformation behavior is analyzed;the material removal mechanism of SiCp/Al is investigated by simulating the material removal of a single diamond abrasive using nanoindentation experiments;the normal force,shear force,impact force and SiC phase fracture force between the diamond abrasive and the workpiece surface are analyzed to establish a polishing force model for NVMRF and to investigate the effect of vibration parameters on the polishing force;the material removal rate(MRR)model is established to reveal the material removal mechanism of SiCp/Al during NVMRF through the microscopic removal of a single diamond abrasive.(3)Simulation and experimental study of NVMRF SiCp/Al.Based on the largescale atomic molecular parallel simulator LAMMPS,a representative analysis unit of SiCp/Al was established to investigate the effect of different vibration modes on the "step height";using ABAQUS finite element analysis software,a SiCp/Al composite model was established to simulate the material removal behavior of a single diamond abrasive under different vibration parameters.The effect of vibration parameters on material removal was investigated.On this basis,NVMRF experiments were carried out on SiCp/Al to investigate the effect of vibration parameters on the surface quality,polishing force,and MRR,proving that NVMRF can improve the machinability of SiCp/Al.