Research On Micro-machining Simulation Of SiCp/Al Composite And Improvement Of Machinability

Compared with traditional alloy materials,SiCp/Al composites have higher specific modulus,specific stiffness and specific strength,and better dimensional stability.They are widely used in modern aerospace,optical precision instruments,electronics,medical and other fields.The finite element modeling method was used to simulate the micro-cutting process of SiCp/Al composite materials,and the improvement of the machinability of the material by minimum quantity lubrication and laser surface melting modification process was studied.It is of great significance to study the cutting mechanism of this materials in micro-machining,improving tool wear and surface machining quality.This paper focuses on micro-machining process finite element simulation,minimum quantity lubrication and laser surface melting modification for SiCp/Al composite.The main contents are as follows:The modified JC constitutive model considering the material strengthening effect caused by the plastic strain gradient is used to describe the cutting behavior of the matrix material in the micro-machining process.The friction coefficient between the tool and the workpiece based on a three-phase friction coefficient model that considers particle two-body sliding,particle three-body rolling and matrix adhesion is calculated,and combined with the sliding-sticking friction model,the friction behavior of the tool rake face and the workpiece during the cutting process is more accurately described.The interface cohesive model is used to describe the mechanical behavior of the interface between the matrix and the particles.Using the JC fracture model and the brittle fracture model to describe the failure of the matrix and the particle in the micro-cutting simulation process respectively.Based on the research of micro-cutting modeling,a micro-cutting model ofSiCp/Al composite material considering the three-phase material of matrix,particles and interface is established.The accuracy of the modeling method is verified through experimental comparative analysis of cutting force,surface morphology,and chip morphology.Then the relevant finite element simulation analysis is carried out,mainly including the effect of different positions of particles relative to the cutting path on the surface morphology,stress distribution and chip morphology during the cutting process,and the study of the minimum undeformed chip thickness.Through the two-dimensional milling simulation and the combination of experiments,the effect of reinforced particles on the machining surface defects and tool wear in micro-cutting of SiCp/Al composites was revealed.The effect of the minimum quantity lubrication on surface roughness and tool wear was studied through experiments.The principle of the laser surface melting modification of this material is revealed,and preferred laser processing parameters were selected to perform laser surface melting modification treatment on 20% and 40% volume fraction SiCp/Al composite materials,and the precision milling and flying cutting methods are used to evaluate the processing performance of the modified material.