纯钨电子束选区熔化过程的温度场有限元模拟  

Finite Element Simulation of Temperature Field During SEBM Process of Pure Tungsten

作　　者：江静 安宁[2] 杨广宇[3] 王建[3] 汤慧萍[3] 李梅娥 Jiang Jing;An Ning;Yang Guangyu;Wang Jian;Tang Huiping;Li Meie(State Key Laboratory for Mechanical Behavior of Materials,Xi’an Jiaotong University,Xi’an,Shaanxi 710049,China;School of Aeorspace,Xi’an Jiaotong University,Xi’an,Shaanxi 710049,China;State Key Laboratory of Porous Metal Materials,Northwest Institute of Nonferrous Metal Research,Xi’an,Shaanxi 710016,China)

机构地区：[1]西安交通大学金属材料强度国家重点实验室,陕西西安710049 [2]西安交通大学航天航空学院,陕西西安710049 [3]西北有色金属研究院金属多孔材料国家重点实验室,陕西西安710016

出　　处：《中国激光》2022年第8期54-65,共12页Chinese Journal of Lasers

基　　金：科学挑战专题项目资助(TZ2018006)。

摘　　要：针对金属材料的电子束选区熔化过程,建立了瞬态温度场及熔池演化的有限元模拟方法。采用双椭球热源模型模拟移动电子束,给出了基于传热机理考虑材料物性参数随材料状态及温度变化的粉末热物性参数估算实现方法,并对有限元模拟方法进行了解析解验证。在此基础上对纯钨的电子束选区熔化过程进行了模拟,单道扫描模拟结果表明,随电子束扫描速率的增大,或电子束半径的增大,或热源功率的减小,熔池最高温度降低,熔池的长度、宽度及深度均减小。两层多道扫描的模拟结果表明,除第一层第一道外,熔池温度场及熔池形貌不对称于扫描中心线,已扫描侧的热影响区大,温度梯度小,熔池面积小。通过模拟得到的熔池剖面图,可预测一定工艺参数条件下多道之间的搭接及多层之间的熔合情况。Objective Tungsten(W)is an important refractory metal with outstanding properties such as high melting point,low vapour pressure,high tensile strength and low thermal expansion coefficient.Such properties render the metal many potential applications in the area of aerospace,aeronautics and nuclear industry.Due to the high melting point and brittle-to-ductile transition temperature,tungsten is typically manufactured by powder metallurgy(PM)techniques.But it is difficult to produce parts with complex structures owing to the intrinsic limitation of the PM techniques.In recently developed additive manufacturing(AM)technologies,high-energy sources are used to fabricate components in a layer-by-layer fusion according to the digital models of the components directly,which facilitates the fabrication of components with complex structure.Selective electron beam melting(SEBM)utilizes electron beam to melt and fuse metal powders to build solid parts.SEBM technology has many advantages such as high energy density,deep energy penetration,high scan speed and low part residual stress.Heat transport is an important physical phenomenon in SEBM.The temperature field evolution during the SEBM process determines the geometry of the molten pool as well as the solidification microstructure and the thermal stress.Because SEBM is conducted in vacuum-tight chamber,research on the heat transport by experiments is relatively difficult.It is necessary to study the heat transfer by numerical simulation to optimize the process parameters.Methods A finite element strategy was developed to simulate the transient temperature field and the molten poolevolution for the SEBM process of metals.The double-ellipsoidal heat source model was adopted to model the moving electron beam.The thermo-physical properties of powders were derived based on the heat transfer mechanism,and the variations of material properties with the state and temperature of the material were incorporated in the numerical model.The ABAQUS user subroutines were developed.The numeri

关 键 词：激光加工 电子束选区熔化 纯钨 温度场 熔池 有限元模拟 

分 类 号：TG47:TN101[金属学及工艺—焊接]