强制流动下铝铜合金激光焊接熔池凝固过程组织演化模拟  

Simulation of Microstructure Evolution During Solidification Process in Laser Welded Molten Pool of Al-Cu Alloy Under Forced Flow

作　　者：蔡佳思 刘湘波 王新元 魏艳红[1,2] CAI Jiasi;LIU Xiangbo;WANG Xinyuan;WEI Yanhong(School of Materials Science and Technology,Nanjing University of Aeronautics and Astronautics,Nanjing 211106,China;Wuxi Research Institute,Nanjing University of Aeronautics and Astronautics,Wuxi 214100,Jiangsu,China)

机构地区：[1]南京航空航天大学材料科学与技术学院,南京211106 [2]南京航空航天大学无锡研究院,江苏无锡214100

出　　处：《材料导报》2024年第19期224-230,共7页Materials Reports

基　　金：国家自然科学基金(52275341);南京航空航天大学博士研究生跨学科创新基金(KXKCXJJ202307)。

摘　　要：建立一个元胞自动机-有限差分-格子玻尔兹曼耦合模型(CA-FD-LB coupled model),对Al-Cu合金激光焊接熔池凝固全过程枝晶的演化开展模拟研究。模拟结果表明,顶盖驱动流一级、二级涡位置和文献结果吻合得非常好;等温纯扩散条件下,枝晶尖端生长速度与过冷度的关系和Lipton-Gilicksman-Kurz(LGK)模型的结果吻合良好。对流作用下枝晶的生长形貌呈现出不对称性,是因为枝晶上游尖端在流动挤压冲刷作用下溶质扩散层变窄,浓度梯度变大,生长得到促进,下游反之。此外,对流加速凝固过程,缩短了凝固时间。焊缝柱状晶平均长度的模拟和实验测量结果分别为117μm和91μm,相对误差约为28.6%,可见耦合模型可靠。In this work,a cellular automaton-finite difference-lattice Boltzmann(CA-FD-LB)coupled model was developed to simulate dendrite evolution during the whole solidification process of the Al-Cu alloy welding pool.The first and second vortices’locations in the lid driven flow were simulated.And the results show a high agreement with the results that have been published in the literature.The quantitative relationship between the growth rate of dendritic tip and the undercooling under isothermal pure diffusion circumstances exhibits outstanding agreement with the predictions of the Lipton Glicksman Kurz(LGK)model.In the presence of external flow,the growth morphology of dendrites demonstrates asymmetry because the solute diffusion layer at the upstream tip of the dendrites becomes narrower under the effect of squeezing of flow,resulting in a larger concentration gradient that promotes growth.Conversely,the downstream region exhibits the opposite behavior.Additionally,flow enhances the solidification process,leading to a shorter solidification time.The results of simulation and experiment are 117μm and 91μm respectively,and the relative error is about 28.6%,showing the reliability of the coupled model.

关 键 词：铝合金 激光焊 组织模拟 元胞自动机 格子玻尔兹曼 

分 类 号：TG456.7[金属学及工艺—焊接]