激光-超声振动辅助切削SiCp/Al复合材料颗粒断裂去除行为及表面质量研究OA

SiCp/Al metal matrix composites are fabricated with aluminum alloy as the matrix and silicon carbide ceramic particles as the reinforcing phase.The two constituent materials complement each other and endow the composite with outstanding comprehensive performance.The fabricated material features low density and remarkable lightweight advantages,excellent thermal conductivity,and tunable coefficient of thermal expansion by adjusting the SiC particle content,which enables favorable thermal turning with semiconductor chips and ceramic substrates.It also boasts strong shock resistance and superior dimensional stability under temperature fluctuations.Meanwhile,the composite possesses high stiffness,favorable wear resistance,and anisotropic mechanical properties.It retains the electrical conductivity of aluminum,supports welding and electroplating,and exhibits satisfactory corrosion resistance and electromagnetic shielding capacity,making it widely applicable to electronic packaging and aerospace precision components.Nevertheless,the uniformly dispersed ultra-hard SiC particles in the aluminum matrix lead to large turning resistance and severe tool wear,which greatly restrict its forming process.Conventional turning suffers from high processing difficulty and excessive manufacturing cost.To achieve precision machining of SiCp/Al composites,a laser-ultrasonic vibration hybrid turning method has been proposed by researchers.Elucidating the fracture evolution mechanism of reinforcing particles and the corresponding material removal laws is of vital theoretical value and engineering guiding significance for optimizing the turned surface forming quality of SiCp/Al composites,accurately selecting turning parameters,and establishing an efficient manufacturing framework. In this paper,a mesoscopic turning simulation model of SiCp/Al composites is established based on Abaqus finite element software.Combined with particle stress distribution and matrix plastic deformation characteristics during turning,four turning processes,namely laser-ultrasonic vibration assisted turning,laser assisted turning,ultrasonic vibration assisted turning and conventional turning,are compared and analyzed.The distinctions in SiC particle fracture modes,crack propagation paths and material removal mechanisms under different thermomechanical coupling conditions are clarified.Numerical simulations are utilized to characterize superficial micro-damage induced by different turning processes.Corresponding turning experiments are carried out.A Zygo interferometer is adopted to accurately measure surface roughness under the four turning schemes,and a scanning electron microscopy(SEM)is used to capture surface micro-morphologies.The measured topography and roughness data are applied to verify the accuracy of the simulation model.Furthermore,the influence laws of cutting speed,depth of cut and feed rate on surface roughness for each turning method are systematically investigated. Simulation and experimental results demonstrate that the hybrid laser-ultrasonic turning realizes synergistic effects of thermal softening of the aluminum matrix,thermal embrittlement of SiC particles and high-frequency dynamic impact.This coupling effect triggers controllable and progressive brittle fracture of SiC particles and maintains a stable and ordered material removal process.Compared with conventional turning,the optimized hybrid turning reduces surface roughness Ra by up to 24.86%.This technology can effectively suppress typical turning defects including particle spalling,deep surface scratches and matrix tearing,delivering optimal performance in improving the surface integrity of workpieces.In addition,turning parameters significantly modulate the functional performance of the hybrid energy field and directly determine the improvement range of turned surface quality.Therefore,reasonable matching and selection of processing parameters according to practical manufacturing demands serve as an essential prerequisite to fully exploit the advantages of this hybrid turning technology and realize high-quality turning of SiCp/Al composites