Research On The Mechanism Of Ultra-precision Machining Of Textured Surface Silicon Carbide By Single Crystal Diamond Abrasiv

In recent years,silicon carbide(SiC)has been widely used in aerospace,integrated circuits and satellite communication for its high band-gap width,strong breakdown electric field and strong radiation resistance.With the development of ultra-precision machining technology,the application of SiC materials tends to be miniaturized,lightweight and integrated,so the requirements for machining precision of surface are increasingly high.However,SiC is a hard and brittle material,and problems such as brittle fracture often occur during the processing.Traditional processing methods are difficult to meet the processing requirements and production efficiency of products.Molecular dynamics(MD)simulation method can effectively reveal the internal microscopic changes of materials during processing,and is an effective method to study the evolution of atomic scale.As a surface modification technology,micro/nano texture can effectively solve the problems of stress concentration,friction and wear,and subsurface damage during machining.Therefore,in this paper,computer simulation software LAMMPS was used to simulate the ultra-precision machining of SiC with single textures,composite textures,and different size textured surfaces.Through comparative analysis of the evolution of material internal defects and the changes of various variables during the machining process,and combining theoretical research,the influence of textured surfaces on SiC processing quality and the advantages of comparing non textured surfaces were obtained.(1)Atomic models for grinding SiC with single shape textured surfaces with diamond abrasive particle were established.The surface morphology,temperature,grinding force,dislocation and subsurface damage of the workpiece on different textured surfaces were obtained.At the same time,the textured surface and non-textured surface were compared and analyzed.Research has found that the presence of textured surfaces significantly improves the fluctuations of various variables during SiC grinding,especially the reduction of grinding temperature and subsurface damage layer depth.It is evident that textured surfaces are beneficial for the high-quality processing requirements of SiC.In addition,groove and cylindrical convex textures are more effective in improving processing quality compared to other texture types.(2)In order to further investigate the effect of texture on SiC processing,the influence of composite textured surfaces on SiC was studied on the basis of single shape textured surfaces,where composite textured surfaces are composed of different single textures.By establishing grinding models of SiC with composite textured surfaces,the temperature,potential energy,grinding force,dislocations,and subsurface damage during the machining process were analyzed,and the results were compared with those of a single textured surface.The results showed that the convex texture can reduce the contact area between the workpiece and abrasive particle,while the concave texture can well accommodate and discharge debris to reduce friction resistance.In addition,the composite texture combines the excellent performance of single textures,and is superior to a single texture in improving grinding processing,especially the surface performance of the composite texture composed of concave and convex is better.(3)The dimension parameters of the texture were studied,and the ultra-precision polishing models of the grooves surface with different depth,width and spacing and the pits surface with different depth were established.The simulation results of different dimensions of the texture were analyzed by the method of control variables.Research has found that the larger the width,depth of the groove,and the pit depth,the smaller the polishing temperature,potential energy,friction coefficient,and subsurface damage.However,a larger groove spacing does not significantly improve the polishing quality.