Study On Ductile-regime Mechanism And Experiment Of SiC Monocrystal

Brittle materials are widely used in electronic and optical industries due to their unique electronic,physical,and chemical characteristics,brittle materials are prone to generate cracks in machining process due to their high hardness and brittleness,which makes machining surface deteriorated.Hence,it’s hard to obtain a ideal finish surface.In recent years,researchers found that the machining of brittle materials exist ductile regime under certain conditions.Ductile-regime machining is drawing more and more attention as a effective method of machining brittle materials.The study of ductile-brittle transition of glass,quartz,silicon for foreign and domestic scholars provides support for the study of ductile-brittle transition of brittle materials.Six single point diamond tool with different included angle and radius is used to make scratching experiment on SiC monocrystal based on the understanding of ductile-regime mechanism of SiC monocrystal.Acoustic emission,friction and load sensors are used to monitor the intensity of acoustic emission and the change in friction during the experiment.In order to study the critical depth of cut in different included angle and radius,using Leica DCM3D and SEM to observe surface morphology and chip state.From the view of energy consumption,this thesis analyzes the differences in the energy consumption of the ductile and brittle mode,the energy consumption on the ductile-regime machining include three sources,energy consumption on brittle-regime include ductile deformation energy and brittle fracture energy.We can obtain the theoretical critical depth of cut of SiC monocrystal by modeling the specific cutting energy of ductile mode and brittle mode.For micro-machining systems requiring high precision,making use of the advantage of piezoelectric ceramics and flexible hinge,a high-precision and two-dimensional minute adjustment platform is designed based on piezoelectric ceramics and flexible hinge.Focusing on leveling principles and conceptual design are discussed in detail.Experiment results proved the effectiveness of conceptual design of the platform.