Study On 4H-SiC Ultra-precision Grinding Mechanism Of Ductile Mode Based On Molecular Dynamics

SiC single crystal material has became the representative of the third generation semiconductor material because of its wide band gap and high electron mobility.Ultraprecision grinding is gradually becoming its main processing technology,which has good processing effect on hard and brittle material SiC single crystal,but it still leaves inevitable machining damage to the wafer.At present,the study of SiC ultra-precision grinding mechanism based on experimental means is not perfect enough,in-depth study of SiC single crystal ultra-precision grinding mechanism is of great guiding significance to realize efficient grinding of SiC single crystal with good flatness,low surface roughness and low subsurface damage.Molecular dynamics simulation can be used to analyze the characteristics of atomic models at the micro scale.It has been widely used in physics,materials,medicine and other research fields,and has been gradually extended to the field of mechanical processing.The ultra-precision ductile grinding mechanism of 4H-SiC can be studied from the microscopic process by applying molecular dynamics simulation.It also can make up for the deficiency of current research based on experimental methods.This study has important theoretical significance and engineering application value.In this paper,based on the 4H-SiC ductile ultra-precision grinding simulation based on molecular dynamics,the grinding mechanism was systematically and deeply studied from grinding quality,grinding force and equivalent stress,potential energy and temperature,etc.And the simulation effectiveness was analyzed by the comparison with experimental data.The main research contents are as follows:(1)Based on molecular dynamics grinding simulation,the 4H-SiC ductile material removal mechanism was analyzed.The molecular dynamics grinding simulation model was established by selecting appropriate simulation parameters.Based on the grinding simulation results,the grinding mechanism of 4H-SiC single crystal was analyzed from the perspectives of grinding surface quality,grinding force and equivalent stress,system potential energy and temperature,etc.,and the grinding simulation results of diamond grinding grains and copper based diamond grinding grains were compared.(2)Based on the Cu matrix abrasive grinding simulation model,the influence of different grinding parameters(grinding speed,grinding depth and abrasive radius)on the surface quality of 4H-SiC grinding was studied.And the grinding force and the effect force,potential energy and temperature was used to explain the cause of this effect,The trend will be compared with the actual grinding experiments.(3)The grinding mechanism of micro cracks was analyzed based on the grinding simulation model of Cu matrix abrasive grains.The formation and propagation behavior of the crack in cutting and other preprocessing stages were analyzed.4H-SiC material models with different relative positions of microcracks were established to study the material removal behavior,grinding force and grinding stress changes in grinding simulation.