Study On Homogenization Of SiCp/Al Composites In Ultrasonic Vibration-assisted Cutting

SiCp/Al composite,which has the advantages of both aluminum alloy and silicon carbide,is a good integrated structure-function material.However,the mechanical properties of the reinforcement and matrix differ greatly,and the aggregation and uneven distribution of many hard-brittle and hard-to-machine silicon carbide particles make it inhomogeneous,anisotropic and non-malleable.The failure criterion and mechanical behavior in the machining process are different from homogeneous substances and become frequently challenging to machine materials.The unstable machining process when using traditional mechanical machining methods has a serious impact on the surface integrity and service life of the workpiece,limiting its practical application.Therefore,how to achieve homogenized processing with excellent efficiency and minimal damage has been a significant obstacle to the advancement of composites.Ultrasonic vibration-assisted cutting(UVAC)has been widely used in precision and ultra-precision machining of many kinds of difficult-to-machine materials,and has been widely recognized for its many advantages in the machining of composite materials.In this paper,the material removal mechanism and the effect of different processing parameters on the cutting force and machined surface morphology of SiCp/Al composites processed by ultrasonic vibration(UV)with different vibration directions are studied by finite element simulation and experimental verification.It provides a theoretical basis for achieving more efficient homogenization cutting of SiCp/Al composites.The main contents of this paper include the following parts:(1)According to the tool path characteristics of ultrasonic vibration cutting in different vibration directions,the key parameters such as net cutting time and instantaneous cutting thickness are characterized,which provide a theoretical basis for the cutting force model.Based on the vibration theory of the variable cross section bar,the structure and performance of the key components of the device are designed and simulated,and the ultrasonic assisted turning device for real-time measurement of cutting force is developed and built.(2)According to the dynamics of SiCp/Al composites in different deformation regions,using shear deformation theory and material constitutive relationship,the cutting force model in conventional machining is combined with the ultrasonic vibration characteristic function.A theoretical cutting force model for ultrasonic vibration machining of SiCp/Al composites along the cutting speed direction and cutting depth direction is established,which takes into account ultrasonic impact force,instantaneous cutting thickness variation and periodic separation characteristics.(3)The second development script of finite element geometry model is constructed in programming language,and three kinds of SiCp/Al composites with different particle shapes are modeled.J-C constitutive model of matrix,JH-2 constitutive model of particle and cohesive model of interface layer developed using elastoplastic fracture mechanics are introduced.The finite element analysis of ultrasonic vibration cutting of SiCp/Al composites was carried out,and the effects of different process parameters on average cutting force and peak cutting force were investigated.In-depth analysis of the material removal mechanism and tool path and particle removal mode of the inherent relationship between them.(4)In order to verify the advantages of ultrasonic vibration machining for SiCp/Al composites,the comparison test of ultrasonic vibration cutting with conventional cutting(CC)and the single factor experiment with amplitude,cutting depth and spindle speed as variables were carried out.The experimental results show the validity of the theoretical analysis and simulation,and further study the effect and mechanism of processing parameters on surface roughness.In this paper,conventional cutting and ultrasonic vibration cutting with different process parameters are studied by theory,simulation and experiment.A reference cutting force prediction model and a finite element simulation model are established.The results show that ultrasonic processing can reduce cutting force and enhance surface quality to a certain extent.Ultrasonic vibration in the direction of cutting speed can obtain the better machining effect.In a certain range of parameters,the selection of smaller cutting depth,moderate ultrasonic amplitude and cutting speed,and other parameters of ultrasonic vibration machining SiCp/Al composites,is conducive to the realization of high efficiency and low damage homogenization cutting.