中空环形激光热源建模及温度场有限元模拟  

Modeling of Hollow Ring Laser Heat Source and Finite Element Simulation of Temperature Field

作　　者：徐加超 夏志新[1] 陈鹏[1] 石世宏[1] 黄树海[2] 王梁 Xu Jiachao;Xia Zhixin;Chen Peng;Shi Shihong;Huang Shuhai;Wang Liang(Institute of Laser Manufacturing Technology,Soochow University,Suzhou,Jiangsu 215006,China;Southwest Technology and Engineering Research Institute,Chongqing 400050,China;Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou,Zhejiang 310014,China)

机构地区：[1]苏州大学激光制造技术研究所,江苏苏州215006 [2]西南技术工程研究所,重庆400050 [3]浙江工业大学激光先进制造研究院,浙江杭州310014

出　　处：《中国激光》2021年第17期25-34,共10页Chinese Journal of Lasers

基　　金：国家自然科学基金(51701134,52071124,U2030102)。

摘　　要：热源类型、工艺参数及产生的温度场分布、热循环特性等对激光熔覆成形件组织和性能有重要影响。中空环形激光熔覆技术因其采用光内送粉,具有光粉全程耦合、粉末集束性好、熔池温度分布均匀等特点,利于获得表面光洁、组织性能良好的成形件。为深入研究熔覆过程中的温度场特性及其对组织性能的影响规律,构建了中空环形热源数学模型,获得其理论解析式,其后通过测定熔池尺寸以及光斑尺寸确定模型参数,最后利用ABAQUS软件模拟中空环形热源移动时的温度场分布及热循环曲线。结果表明,实验测试的温度场分布与模拟分析一致,热循环模拟曲线也与实测值高度吻合,由此可得该中空环形热源模型有较好的精度和适用性。Objective Control of microstructure and residual stress,and optimization of process parameters based on the temperature field are important methods to improve mechanical properties of the cladding parts.A relatively accurate laser heat source model should be provided to reconstruct the temperature field during the formation of the cladding layer.First,an accurate mathematical model of hollow ring laser heat source,which should be verified by numerical simulation and the experiment results,needs to be constructed to obtain the fundamentals for a practical temperature field,microstructure distribution,residual stress control,and process parameters optimization.The temperature distribution inside the molten pool could be reflected precisely by an appropriate heat source model to simplify the numerical calculation and deeply explore the influence of temperature gradient and cooling rate on residual stress and actual solidification microstructure during the solidification and cooling process.Since Goldak proposed the classical double ellipsoid heat source in 1984,a wide variety of heat source equations have been generated based on the mathematical modeling evolution of solid heat sources.However,the mathematical model of the hollow ring heat source based on the inside-laser coaxial powder-feeding system was rarely studied.A simple and practical heat source equation should be established to verify the reliability of the model through the combination of experiment and theory analysis.Methods Based on the finite element software called ABAQUS and the hollow ring laser system,the energy distribution discipline of the hollow ring laser was verified by the probe beam quality analyzer,and a formal hollow ring laser heat source equation was proposed.The energy density determined by numerical analysis was used to establish the final mathematical equation.Response surface method(RSM)was adopted after the hollow ring laser heat source equation was established.The fitting equation of molten pool size under mutative process parame

关 键 词：激光技术 激光熔覆 中空环形激光 热源模型 温度场 热循环 

分 类 号：TG174.44[金属学及工艺—金属表面处理]