Research On Micro Cutting Simulation Method And Surface Integrity Of SiCp/Al

Aluminum-based silicon carbide is a kind of metal matrix composite(MMC),which has the advantages of low density,high specific strength,high specific stiffness,high toughness,high wear resistance and good fatigue resistance,as well as high temperature resistance and small thermal expansion coefficient,it is widely used in various fields such as military and civilian,such as aerospace,automotive industry,electronic packaging,optical instruments,etc.However,the aluminum-based silicon carbide composite has high hardness and brittleness,and it is difficult to machine.In the processing of aluminum-based silicon carbide,the tool wear is serious,and the defects generated on the machined surface are many,which leads to the reduction of the accuracy of the cutting,affecting the assembly precision and the service life of the workpiece,and restricts the application of the aluminum-based silicon carbide composite in practice.Therefore,it is very necessary to study the processing technology of aluminum-based silicon carbide composites.In this paper,theoretical and experimental studies on the finite element simulation method and surface integrity of aluminum-based silicon carbide matrix composites are carried out.Firstly,the cutting process of aluminum-based silicon carbide composites was modeled by three methods: first,the equivalent homogeneous model,regardless of the material structure of the aluminum-based silicon carbide composite,the constitutive equation only reflects the properties of the homogeneous material;multiphase mixture model,aluminum matrix and SiC particles adopt different constitutive models to observe the change of material structure during cutting;third,multiphase mixture cohesive model,which is based on multiphase mixture model.The combination of SiC particles and aluminum matrix is by cohesive element which can better simulate the stress transfer process and the debonding process of SiC particles.Then,the single-factor micro-milling experiment was carried out on the aluminum-based silicon carbide composite,and the defects generated on the machined surface were observed and the energy spectrum analysis was carried out.Then the cutting mechanism of the aluminum-based silicon carbide composite was studied,and then the surface micro-morphology was detected.And the roughness and microhardness of the machined surface was measured,to study the surface micro-morphology,surface roughness,and micro-hardness with the change of cutting parameters.The results show that the order of influence degree of each factor on surface roughness is feed rate,spindle speed and cutting depth,and the order of influence degree on surface quality is feed rate,spindle speed and cutting depth.The surface quality of the down milling zone is better than that of the up milling zone.Finally,the simulation results are analyzed,and the changes of cutting force,cutting temperature of tool tip and chip and surface stress are extracted from the equivalent homogeneous cutting model.The debonding and breaking of SiC particles in the cutting process of the multiphase mixture model and the multiphase mixture cohesive model were also investigated.Comparing the defects in the actual micro-cutting surface,the correctness of the simulation model and method is proved.