Research On Machining Mechanism Of SiCp/Al Composite By Pulsed Laser-Ultrasonic Vibration Assisted Cutting

Aluminum-based Silicon Carbide(SiCp/Al)composite materials are widely demanded in various critical fields such as rail transportation,aerospace,medical devices,and defense due to their advantages of high strength,high wear resistance,and low density.However,SiCp/Al composite materials contain both hard SiC particles and a softer Al matrix,leading to issues in conventional machining processes,including SiC particle pull-out,fracture,breakage,and interface detachment between SiC particles and the Al matrix.Consequently,its challenging machinability restricts the widespread use of this material.In order to improve the machining quality,enhance processing efficiency,and reduce machining costs of SiCp/Al composite materials,a pulse laser-ultrasonic vibration-assisted cutting method has been proposed to enhance the machinability of SiCp/Al composite materials.This paper primarily investigates the cutting mechanism of SiCp/Al composite materials,analyzes the cutting forces,cutting temperature,damage mechanism of SiC particles,and the evolution of chip formation process and morphology during pulse laser-ultrasonic vibration-assisted cutting of SiCp/Al composite materials.(1)For the pulse laser-ultrasonic vibration-assisted cutting method,develop an experimental processing system and study the processing mechanism of pulse laser-ultrasonic vibration-assisted cutting of SiCp/Al composite materials.First,based on the motion trajectory of the two-dimensional ultrasonic vibration-assisted cutting tool,a two-dimensional ultrasonic vibration-assisted cutting device is developed,and harmonic response analysis is used to determine whether the structural dynamics characteristics of the device meet the processing requirements.Then,impedance analysis and vibration amplitude test experiments were conducted on the prototype of the two-dimensional ultrasonic vibration-assisted cutting device to verify the performance parameters of the device.Finally,a pulse laser-assisted processing system was built and installed on the precision lathe together with the ultrasonic vibration-assisted cutting device to complete the construction of the experimental bench.In addition,pulse laser is used to impact SiCp/Al composite materials,the processing mechanism of pulse laser on SiCp/Al composite materials is analyzed,and the physical phenomena that occur when pulse laser impacts SiCp/Al composite materials are revealed.(2)A prediction model of the temperature field was established,and the finite element simulation method was used to analyze the removal process of SiC particles when cutting SiCp/Al composite materials,revealing the characteristics of material removal and the removal mechanism under different particle distribution forms.First,based on the dynamic constitutive model of SiCp/Al composite material that considers particle damage characteristics,a cutting force model for ultrasonic vibration-assisted cutting of SiCp/Al composite material is established.Then,through the classic three-dimensional heat conduction model,an analytical model of the workpiece temperature field caused by Gaussian distributed pulse laser is established;finally,the model of cutting force and cutting temperature is combined to predict the temperature of pulse laser-ultrasonic vibration-assisted cutting of SiCp/Al composite materials.In addition,an infrared thermal imaging camera was used to measure the average temperature of the tool-chip contact surface and compare it with the finite element simulation temperature and predicted temperature to verify the validity of the model.The cutting simulation of SiCp/Al composite materials was also used to analyze the removal behavior of SiCp/Al composite materials and reveal the surface improvement mechanism of SiCp/Al composite materials by pulsed laser-ultrasonic vibration-assisted cutting.(3)Analyze the chip formation mechanism and tool wear mechanism of cutting SiCp/Al composite materials using different processing methods.First,through in-situ cutting experiments,the differences in chip morphology between conventional cutting,pulse laser-assisted cutting and pulse laser-ultrasonic vibration-assisted cutting were explored.Then,the friction characteristics of the tool-chip interface and the damage on the chip surface during the chip formation process are analyzed to reveal the impact of pulsed laser-ultrasonic vibration-assisted cutting on the arrangement of SiC particles in the chips.In addition,the evolution process of laser parameters and cutting parameters on chip morphology and the changing rules of chip morphology were explored,and the correlation between the friction effect of the tool-chip interface and chip morphology was explained.Finally,by observing the tool wear after cutting SiCp/Al composite materials,the damage to the rake and flank surfaces of tools in different processing methods was analyzed,and the tool wear mechanism of cutting SiCp/Al composites was revealed.(4)Explore the changes in cutting force and cutting heat when cutting SiCp/Al composites using different processing methods,and analyze surface and subsurface damage as well as microscopic damage mechanisms.First,the surface damage pattern when cutting SiCp/Al composite materials was analyzed through surface morphology testing.Then,according to the thermal softening temperature of the SiCp/Al composite material,the influence of laser parameters on the temperature of SiCp/Al is explored and reasonable laser processing parameters are determined.In addition,the influence of different process parameters on cutting force and surface/subsurface damage is explored to provide an important basis for selecting appropriate cutting parameters.Finally,the micro-cutting mechanism when cutting SiCp/Al composites is revealed by analyzing the changes in grain size,subsurface stress and microstructure of SiCp/Al composites after processing.This also provides theoretical guidance for improving the processability of SiCp/Al composite materials.