超声振动切削对SiCf/Al去除机理与表面形貌的影响OA

Continuous fiber-reinforced metal matrix composites,such as SiC fiber-reinforced aluminum(SiCf/Al),have gained increasing attention in advanced engineering applications for their high specific strength,lightweight nature,and excellent mechanical performance under extreme conditions.However,the inherent heterogeneity and anisotropy of these composites,arising from the coexistence of brittle ceramic fibers,ductile metallic matrices,and interfacial transition zones,pose significant challenges for high-quality machining.During conventional cutting(CC),the mismatch in mechanical properties between the fiber and matrix often results in severe defects,including fiber fracture,interfacial debonding,matrix tearing,and fiber pull-out,ultimately degrading surface integrity and machining stability.To address these challenges,this study systematically explores the material removal mechanism and the development of surface morphology in SiCf/Al composites during ultrasonic elliptical vibration cutting(UEVC).A three-dimensional micromechanical cutting model incorporating SiC fibers,the aluminum matrix,and their interfacial behavior is created using the ABAQUS explicit dynamic method.Comparative simulations between CC and UEVC are carried out at various cutting depths(5-25 μm)to analyze differences in stress distribution,deformation modes,and damage evolution.Within the cutting depth range of 5-25 μm,the surface roughness processed by UEVC increases from 0.115 μm to 0.224 μm,while the surface roughness processed by CC increases from 0.195 μm to 0.442 μm.Additionally,ultra-precision turning experiments are performed to validate the simulation results,with surface roughness measured utilizing white-light interferometry. The results reveal that UEVC significantly alters the cutting mechanics through its unique tool motion characterized by periodic contact-separation and multi-directional vibration.This intermittent cutting behavior effectively reduces stress concentration and friction accumulation in the cutting zone.Consequently,fiber fracture becomes more localized and regular,while interfacial debonding and fiber pull-out are substantially suppressed.In contrast,under CC conditions,continuous tool-workpiece contact leads to the accumulation of compressive and shear stresses,promoting uncontrolled fiber breakage and extensive interfacial damage.From the perspective of the matrix behavior,the aluminum matrix under UEVC exhibits stable shear-dominated plastic flow with reduced lateral material accumulation and surface pile-up.This contributes to the formation of smoother and more uniform surface morphology.On the contrary,in CC,the matrix undergoes severe plastic side flow and plowing,resulting in pronounced surface irregularities and defects.As the cutting depth increases,both methods exhibit a degradation in surface quality;however,UEVC shows a much slower deterioration rate and superior process stability.Experimental observations further confirm that UEVC produces surfaces with lower roughness and more consistent topography across different cutting depths.The periodic separation between the tool and workpiece reduces instantaneous cutting forces and mitigates secondary damage to the surrounding matrix after fiber fracture.As a result,the synergistic removal of fibers and the matrix is enhanced,transforming the material removal mode from uncontrolled composite damage to a more predictable shear-dominated process.In summary,ultrasonic elliptical vibration cutting effectively improves the machining performance of SiCf/Al composites by modifying the tool-workpiece interaction mechanism and redistributing the cutting load.It enables coordinated control over brittle fiber fracture and ductile matrix deformation,thereby significantly enhancing surface integrity and reducing subsurface damage.This study provides both theoretical insights and experimental evidence for understanding the micro-scale removal mechanisms of heterogeneous composites and offers practical guidance for achieving low-damage,high-quality machining of continuous fiber-reinforced metal matrix composites.