Study On Drilling Performance Of Silicon Carbide With Different Microstructures

C and Si in silicon carbide are combined in the form of covalent bonds,which have excellent performance,high temperature resistance and wear resistance,so they are widely used in aerospace,automotive,machinery,petroleum and other fields.When SiC is applied,it is often subjected to secondary hole processing.Due to the difference in SiC sintering process and sintering principle,the microstructure of SiC produced is different,often containing certain impurities(C,Si,etc.)and pores,which seriously affects the performance of SiC.Therefore,the phenomenon of collapse and fracture often occurs during the drilling of silicon carbide,which seriously affects the processing quality of silicon carbide holes.In order to improve the drilling quality of SiC ceramics,this paper studies the effects of impurities and pores on the drilling performance of SiC ceramics and the material removal mechanism of SiC ceramics during the drilling process.On this basis,the structural parameters of the brazed diamond tool,drilling process parameters and grinding fluid are optimized to achieve high efficiency and high quality drilling of SiC ceramics.The research content of this paper mainly includes the following points:(1)Firstly,the effects of different sintering processes on the microstructures(impurity content,pore,etc.)of SiC ceramics were investigated,and the mechanical properties of SiC ceramics caused by the differences in microstructures were analyzed.(2)Through single factor experiments,the influence of process factors on drilling quality is analyzed,and the structural parameters of diamond tools are optimized.Based on the optimization of tools,the influence of brazing filler metal ratio on the drilling efficiency of silicon carbide is studied.Finally,brazed diamond tools suitable for silicon carbide drilling are obtained.(3)The wear matching relationship between brazed diamond tools and silicon carbide is established,and verified by experiments,which can guide the drilling of silicon carbide and other engineering ceramics.(4)The drilling mechanism of SiC ceramics was analyzed by theoretical analysis,calculation and experiment.The surface characteristics of the silicon carbide were observed by ZEISS Merlin Compact field emission scanning electron microscope,and the material removal method of silicon carbide during the drilling process was analyzed.(5)According to the cracking and collapse phenomenon of silicon carbide during the drilling process,a prestressing device is designed.By changing the magnitude of the prestress,to improve the drilling quality of silicon carbide,and finally the stress value range suitable for silicon carbide drilling is obtained.