Temperature Field Analysis And Experimental Research Of CMC-SiC Laser-assisted High-speed Micromachining

Silicon carbide ceramic matrix composite(CMC-SiC),as a new strategic thermal structure material,has the advantages of high temperature resistance,wear resistance,thermal shock resistance,fatigue resistance and creep resistance.It has good application prospects in high-temperature thermal structural components such as thermal protection systems for aerospace vehicles,aero engines,rocket engines,high-performance brakes,and advanced nuclear energy.However,CMC-SiC has high hardness and material anisotropy,which is a difficult-to-machine material.Conventional machining(CM)technology is difficult to achieve high-precision,high-quality,and high-efficiency machining.Therefore,it is of important research significance to explore a new type of processing technology to improve its processing performance.Laser-assisted machining(LAM)technology can reduce machining force and machining energy,extend tool life,and improve surface quality.At present,there are very few domestic researchers who apply LAM technology to the CMCSi C processing direction branch.In this paper,laser-assisted high-speed micromachining temperature field analysis and experimental research on 3D needle-punched carbon fiber reinforced silicon carbide(Cf/Si C)ceramic matrix composite in CMC-SiC.The specific research content includes the following aspects:Firstly,the mathematical model and finite element model of the CMC-SiC laser heating temperature field are constructed.The correctness of the model is verified through a combination of experiment and simulation.The effects of different laser power densities and workpiece rotation speeds on the CMC-SiC laser heating surface,machining layer and radial temperature field distribution are analyzed.It provides a theoretical basis for the subsequent machining process simulation parameter setting and machining experiment process parameter selection.Secondly,a finite element model of CMC-SiC laser-assisted high-speed micromachining was constructed.Based on CM and LAM,a comparative study of the influence of different workpiece speeds on the chip and tool tip temperature field was carried out.The simulation analysis results are used as the basis for the optimal control of the temperature field in the laser-assisted high-speed micromachining experiment.Thirdly,based on the simulation results of the temperature field,the range of process parameters used in the experiment was obtained,and the CMC-SiC laser-assisted high-speed micromachining experiment research was carried out.Based on the two technical conditions of CM and LAM,a comparative analysis of the influence of different workpiece speed,feed speed,machining depth,and laser power density on machining force and tool wear is carried out.It is concluded that LAM can effectively reduce the machining force in the cutting process and improve tool wear.Finally,a comparative study was made on the influence of various processing parameters on the surface quality of CMC-SiC under CM and LAM conditions.The surface roughness,surface morphology,and surface residual stresses are analyzed,obtaining LAM can significantly improve the surface quality after CMC-SiC machining,which proves the feasibility and effectiveness of the LAM technology.Through the research of the above content,the purpose of controlling the temperature field of CMC-SiC laser-assisted high-speed micromachining,optimizing the process parameters,improving the quality of the processed surface,reducing the machining force,and reducing tool wear is finally achieved.