金属粉末选区激光熔化成形过程温度场模拟_姚化山详解.docx

　第27 卷第6 期　　　　　　　　　　　　　应　用　激　光Vol.27 , No .62007年12 月APPLIED LASERDecember 2007金属粉末选区激光熔化成形过程温度场模拟＊姚化山 , 　史玉升 , 　章文献 , 　刘锦辉 , 　黄树槐(华中科技大学塑性成形模拟及模具技术国家重点实验室, 湖北武汉430074)提要　利用ANSYS 有限元软件对选区激光熔化(Selective Laser M elting , SLM)成形过程的三维瞬态温度场的分布变化进行了数值模拟;在考虑材料的热物性参数随温度变化和相变非线性行为的情况下, 建立了选择性激光熔化(SLM)的三维温度场有限元模型;并利用ANSYS 参数化设计语言(APDL)实现了激光高斯热源的移动加载。模拟结果表明:随着扫描时间的增加, 由于热积累效应, 熔池的温度越来越高, 热影响区也随之增大;熔化成形过程中, 光斑中心的前端存在较大的温度梯度;扫描速度小, 容易造成液相的流动, 出现孔洞, 扫描速度过大, 则粉末不能完全熔化;模拟得到的结果与实验结果相吻合。关键词　选区激光熔化;　有限元模型;　ANSYS 参数化设计语言;　熔池;　液相Numerical Simulation of the Temperature Field in Selective Laser MeltingYao Huashan , 　Shi Yusheng ,　Zhang Wenxian , 　Liu Jinhui,　Huang Shuhuai(State Key Laboratory of Plastic Forming Simulation and Die and Mould Technology , Huazhong Universityof Science and Technology , Wuhan , H ubei 430074 , China)Abstract 　This article uses ANSYS to simulate distribution of the tem perature field in selective laser melting .A three-dimensional transient thermal finite model of SLM is established based on latent heat due to phrase transformation from powder to liquid and thermo physical of materials considered to be temperature-dependent .By using the ANSYS parameter design language(APDL), the moving of laser beam can be controlled.The simulation results show that with the time increasing , the temperature of the molten pool becomes higher and HAZ becomes bigger because of the heat accumulative effect , great temperature gradients exist in the front of laser spot, and that liquid phase flows easily and holes appear because of slow scanning speed, contrarily , the powder can not be melted completely .These agree with the experimental results well.Key words　Selective laser melting ;　finite element model ;　ANSYS parameter design language ;　molten pool ;　liquid phase1　引言选区激光熔化(Selective Laser Melting , SLM) 是一种金属件直接成型方法,是快速成型技术的必威体育精装版发展。该技术采用中小功率激光器(N d:YAG 或光纤激光器),成形材料范围广泛(单一金属粉末、复合粉末、高熔点难熔合金粉末等),成形过程中金属粉末完全熔化,产生冶金结合,可以制得致密度达到100 %、精度达到0.1%的金属成形件[ 1] 。但是由于成形过程中激光束的功率密度高,扫描速度快,金属粉末在