Study On Residual Stress Of SiCp/Al Composites In Milling

SiCp/Al composite materials have high application and development advantages in many industries due to its excellent physical and mechanical properties.However,due to a large number of SiC enhanced particles randomly distributed in the Al matrix,the cutting surface quality has many defects,especially the presence of uneven cutting surface residual stress,which seriously hindered the practical application and development of SiCp/Al composites.Therefore,it is of great practical significance to improve its machined surface quality to study the generation process and mechanism of surface residual stress in machining of SiCp/Al composites.The finite element model of the milling process was established by the finite element analysis method,which defined the properties of the composite materials and the two kinds of two phase materials.The causes of cutting residual stress,the distribution of residual stress along the depth of the layer and the influence of cutting parameters on the residual stress were studied,and the results of the two states were consistent.The formation mechanism and some common defects of SiCp/Al composites were studied by the improved micro model,and the influence of the three party interaction on the residual stress distribution was also investigated.A mathematical model of equivalent milling thickness was established,which was in favor of researching the influence of the speed and the feed per tooth on cutting residual stress.The milling experiments were carried out on the SiCp/Al composite materials,and then the surface residual stress testing was performed after cutting.The results were compared with the simulation results and the accuracy of the simulation results was also verified.Through the research,we found that the surface residual stress of SiCp/Al composite material had the following distribution along the depth of the layer: the most surface stress was compressive stress,and the residual compressive stress in the second layer was reduced,and the tensile stress was beginning to appear,but the tensile stress value was small,and with the depth increasing,the stress tends to zero.The feed pertooth had a great influence on the change of residual stress.With the increase of feed per tooth and equivalent milling thickness,the maximum residual compressive stress on surface and subsurface increases,and compressive stress layer on subsurface and maximum residual tensile stress also increases.With the increase of the cutting speed,the residual stress of the cutting surface had different degrees of fluctuation,and the cutting speed had little effect on the residual stress.