Temperature Field Of Al₂O₃ Ceramics By Laser Heating

Al₂O₃ ceramic materials is widely used in aerospace,laser technology,national defense and other fields because of high hardness,corrosion resistance,oxidation resistance,high temperature,wear resistance,good insulation and other excellent performance.But at the same time,its high hardness,brittleness,poor reliability and the surface of the existence of micro-cracks and pores and other shortcomings of the traditional processing methods is difficult to directly processing.Therefore,technology-laser heating assisted cutting technology came into being.It combined with laser beam energy and advantages of traditional cutting.The key problem of this technology is to control the temperature of the heating material and to select the appropriate processing position.According to the interaction mechanism between the laser and the material,the physical stage of the material heating and the phase change is not realized during the actual processing of the laser heating auxiliary cutting material.Based on the theory of heat conduction,the following work was carried out:1 The research methods of laser welding of Al₂O₃ ceramics in the past is introduced in this paper.Numerical algorithms and analytical algorithms were usually adopted.The numerical algorithm is based on the basic theory of heat conduction.The finite difference method is mainly based on the finite element method and the general analytical expression of the heat conduction equation.Considering that the heated area is much smaller than the size of the workpiece,the analytical algorithm usually assumes that the workpiece is a semi-infinite solid so that the heat conduction equation is simplified the one or two dimensional problems.The calculation result must be different from the actual processing situation.In this paper,when the temperature fieldis solved,it is regarded as a three-dimensional heat conduction problem.2 Based on the working characteristics of the continuous laser heating of the rectangular cube and the round bar Al₂O₃ ceramics,the corresponding rectangular coordinate system and the thermal conductivity mathematical model in the cylindrical coordinate system were established.Using the mathematical physics method,combined with the boundary condition and the initial condition,the heat transfer model of Al₂O₃ ceramic by the laser heating is solved.The results show that the temperature field of the Al₂O₃ ceramics in the steady state and unsteady state is obtained,and the temperature field distribution is calculated and simulated by Mathematica 10.3 software.3 Based on the theory of heat conduction,the mathematical model of pulsed laser heating rectangular box and round bar Al₂O₃ ceramics is established and the mathematical model is calculated.Firstly,the single-pulse heating ceramic is used to start the analysis.Secondly,the temperature of the ceramic is obtained by the temperature superposition principle.The general analytical expression.Finally,the main factors affecting the temperature distribution of Al₂O₃ ceramics,such as laser power,spot radius and laser interaction time were compared and analyzed.The results provide a theoretical basis for laser heating assisted cutting of Al₂O₃ ceramics,and have some reference for the selection of process parameters during the actual processing of Al₂O₃ ceramics.