多维高频振动对激光熔覆成形几何形貌的影响研究  

Effects of Multi-dimensional High Frequency Vibration on Geometrical Morphology of Laser Cladding Forming

作　　者：俞晓文 姚喆赫 张操棋 邢飞 姚建华 聂艳斌[1,2] YU Xiao-wen;YAO Zhe-he;ZHANG Cao-qi;XING Fei;YAO Jian-hua;NIE Yan-bin(Institute of Laser Advanced Manufacturing,Zhejiang University of Technology,Hangzhou 310023,China;Collaborative Innovation Center of High-end Laser Manufacturing Equipment,Zhejiang University of Technology,Hangzhou 310023,China;Key Laboratory of Advanced Manufacturing Technology of Zhejiang Province,Zhejiang University,Hangzhou 310027,China;Nanjing Zhongke Raycham Laser Technology Co.,Ltd,Nanjing 210038,China)

机构地区：[1]浙江工业大学激光先进制造研究院,杭州310023 [2]浙江工业大学高端激光制造装备省部共建协同创新中心,杭州310023 [3]浙江大学浙江省先进制造技术重点实验室,杭州310027 [4]南京中科煜宸激光技术有限公司,南京210038

出　　处：《表面技术》2020年第10期286-293,315,共9页Surface Technology

基　　金：国家重点研发计划项目(2017YFB1103600);国家自然科学基金(51705460,U1809220);浙江省先进制造技术重点实验室开放基金课题(2018KF01)。

摘　　要：目的面向激光表面改性及再制造发展需求,针对激光熔覆过程控形问题,揭示多维振动对激光熔覆涂层几何形貌及多道搭接成形质量的作用机制。方法开展多维振动辅助激光熔覆成形316L涂层实验研究,对单道及多道激光熔覆层横截面形貌进行分析。采用多物理场有限元分析软件,建立多维振动辅助激光熔覆成形模型,并分析熔覆层表层温度梯度。结果数值模拟表明,施加二维振动后,熔池表面流速提高了31.00%,表面流速的提高促进了熔池向外扩展,最高温度梯度减小39.08%,熔覆层横截面几何形貌因温度和流速的变化发生了明显改变。实验结果表明,相比于无振动作用,在一维、二维、三维振动作用下,熔高分别减小了18.97、33.94、44.50μm,熔宽分别增加了27.70、36.90、63.34μm,润湿角最高降低了23.42%。在多道搭接过程中,润湿角增大到某一阈值时,部分搭接区域因吸收激光能量不足而使该处不发生熔化,粉末熔化后难以完全填充角落,致使激光多道熔覆时的熔覆层底部产生气孔,成形质量降低。施加多维振动通过降低润湿角,可以减小多道熔覆中的气孔发生率。结论多维振动通过影响温度梯度有效改善了熔覆层的润湿性,减少了熔覆层气孔的发生率,提高了熔覆层的成形质量。The work aims to reveal the mechanisms of multi-dimensional vibration on the geometrical morphology of laser coating and the quality of multi-track lap forming for the shape control of the laser cladding process,so as to meet the development needs of laser surface modification and remanufacturing.Experimental studies on multi-dimensional vibration-assisted laser cladding of 316L were carried out.The cross-section morphology of single track and multi-track laser cladding layer was analyzed.Multi-dimensional vibration-assisted laser cladding forming model was established by multi-physics finite element analysis software to analyze the surface temperature gradient of cladding layer.The simulation results showed that after two-dimensional vibration was applied,the surface flow velocity of molten pool increased by 31.00%,the increase of the surface flow velocity promoted the outward expansion of the molten pool,the maximum temperature gradient reduced by 39.08%and the cross-section geometrical morphology of the laser single-track cladding coating changed significantly due to the change of temperature and velocity.The experimental results showed that the cladding height reduced by 18.97,33.94,44.50μm under one-dimensional,two-dimensional and three-dimensional vibration,respectively,compared to non-vibration condition.In addition,the cladding width increased by 27.70,36.90,63.34μm,respectively,while the wetting angle decreased by 23.42%at the highest.During the multi-track overlapping process,part of the overlapping area did not melt due to insufficient absorption of laser energy when the wetting angle increased to a certain threshold.The melted powders were difficult to completely fill the corner.Consequently,pores were generated at the bottom of the cladding layer during multi-track laser cladding,which reduced the forming quality.The application of multi-dimensional vibration in multi-track laser cladding reduced the incidence of porosity by reducing the wetting angle.The multi-dimensional vibration effectively imp

关 键 词：激光熔覆 多维振动 几何形貌 润湿角 气孔 数值模拟 

分 类 号：TG174.4[金属学及工艺—金属表面处理]