Research On Cutting Deformation Mechanism And Experimental Of Milling SiCp/Al Composites

SiCp/Al particle reinforced composites have excellent properties such as high specific modulus,high specific strength,high wear resistance,high temperature resistance and high thermal and electrical conductivity.In recent years,particle reinforced composites are widely used in some industrial fields requiring light weight,wear resistance or heat resistance of parts,especially discontinuous reinforced materials such as SiCp/Al composites,which have become an excellent substitute for traditional metals.However,it is difficult to machine them due to the presence of harder Si C reinforcing particles in the material.In this paper,the shear lag model and effective medium approximation method were used to solve the constitutive equation of high volume fraction composites,and the cutting deformation mechanism and numerical simulation of SiCp/Al composites were studied by combining finite element cutting simulation and experiment.The main contents are as follows:Firstly,the quasi-static compression experiment and the split Hopkinson compression bar experiment were carried out on the SiCp/Al particle reinforced composite with a volume fraction of 45%,The relevant experimental equipment and experimental scheme were introduced and the working principle was described.The stress-strain relationship of high volume fraction composites under elastic-plastic deformation was calculated,and the experimental values were compared with the calculated values.The final constitutive equation was transformed into a form,and then this constitutive was applied to the following two-dimensional and three-dimensional cutting simulation models.Secondly,a two-dimensional cutting simulation model was established to simulate and analyze the cutting mechanism from the distribution of stress field,the fracture and crushing mechanism of particles and the crack propagation on the chip surface,which was verified by milling experiments.It was found that the fracture and fragmentation of particles generally occur in the separation surface and shear zone of the workpiece and the chip.At the same time,the existence of particles will produce microcracks on the chip surface,and the propagation of microcracks is an important factor affecting the chip surface morphology.Finally,the three-dimensional SiCp/Al composite cutting simulation model was established by Digimat-FE software,and imported into ABAQUS/Explicit software for cutting simulation.At the same time,combined with the theory of metal cutting,the material removal mechanism and the machining surface creation mechanism in the cutting process were analyzed.And from the experimental point of view,the influence of cutting speed and cutting depth on the surface quality of SiCp/Al composites was analyzed.It was found that increasing the cutting speed appropriately was beneficial to reduce the machined surface defects of SiCp/Al composites and improve the machined surface quality,but with the increase of cutting depth,the machined surface quality will be greatly reduced.