Processing Mechanism and Experiment of Ultrasonic Vibration Assisted Cutting of SiCp/Al Composites
SiCp/Al composites contain high hardness SiC particles and are unevenly distributed in the Al matrix,causing the two-phase material to exhibit non-cooperative deformation during processing,thus resulting in problems in conventional cutting force mutation,such as severe tool wear,low processing efficiency,and poor machining surface quality.The introduction of ultrasonic vibration-assisted cutting(UVAC)is an effective way of improving machining quality.The study of the form of particle damage and the material removal mechanism in UVAC is important.To reveal the machining mechanism underlying a 20％SiCp/Al composite material under UVAC conditions and to study the influence law of different process parameters on the cutting force and machining surface quality,a simulation model based on two-dimensional polygon random distribution particles was established using the finite element simulation software Abaqus.The microstructure,deformation,and failure of the SiCp/Al composites were simulated by considering the cohesive elements of particle fracture,matrix deformation,and tensile force between the particles and matrix.The dynamic cutting process of SiCp/Al composites was simulated for conventional cutting(CC)and UVAC,and the influence of different relative positions between the tool and particles on the particle removal behavior was analyzed.The experimental and simulated cutting forces obtained using CC and UVAC were compared using the same parameters,and the accuracy of the finite element simulation was verified.Through the design of a single-factor experiment,the effects of the two machining methods and different machining parameters on the cutting force and surface roughness were compared,the optimal combination of machining parameters was obtained,and the surface topography under the optimal machining parameters was analyzed.The simulation and experimental results show that SiC particle fracture,particle plowing,particle pulling out,and Al matrix tearing are the main factors affecting the processing quality of SiCp/Al composites.Under both CC and UVAC processing conditions,the cutting force initially decreases and then increases as workpiece speed increases;the cutting force gradually increases with increasing feed rate,and then increases with increasing cutting depth.Different relative positions of the tool and particles produce different forms of damage.When the tool path passes through the middle of the SiC particle,the SiC particle is mainly removed in the form of particle fracture.When the tool path passes through the upper part of the SiC particles,the SiC particles are partially unstuck and deflected,and the particles are more easily pressed into the Al matrix.When the tool path passes through the lower half of the SiC particle,the SiC particle integrates with the tool,thereby changing its front angle.The application of ultrasonic vibrations can effectively inhibit the failure of SiC particles and matrix damage,reduce the fracture damage of particles during cutting,reduce the desticking phenomenon of particles,and stabilize the fractured particles in the matrix.Compared to CC,the average cutting force(main cutting force)in machining was reduced by 33％,and the maximum reduction in the machined surface roughness was 531 nm,which significantly improved the quality of the machined surface.The established two-dimensional microscopic multiphase finite element model can effectively simulate the processing defects and crack damage of aluminum matrix composites,reflect the real particle failure behavior during processing,and identify the mechanism underlying the effect of different relative positions between the tool and the particle on the particle removal behavior.The removal mechanism,surface morphology,and cutting force of the UVAC SiCp/Al composites were investigated by combining experiments and simulations.These results provide significant reference for improving the high-quality surface preparation of difficult-to-machine materials.
ultrasonic vibration-assisted cuttingSiCp/Al compositesprocessing mechanismsurface qualitycutting force
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