近红外光和蓝光激光焊接Ti/Cu异种金属工艺研究  

Laser Welding of Dissimilar Ti/Cu by Near-Infra-Red and Blue Laser

作　　者：周俊 陈灿阳 张晶 龙雨 Zhou Jun;Chen Canyang;Zhang Jing;Long Yu(School of Mechanical Engineering,Guangxi University,Nanning 530004,China)

机构地区：[1]广西大学机械工程学院,广西南宁530004

出　　处：《稀有金属》2023年第5期738-747,共10页Chinese Journal of Rare Metals

基　　金：中央引导地方科技发展专项资金项目(GKZY21195029);广西研究生教育创新计划项目(JGY2021001)资助。

摘　　要：Ti/Cu异种金属结构能兼具两者优势,满足结构低密度、高比强度和高导热需求。由于Cu等有色金属材料对近红外光(NIR)波长激光的高反性,使近红外波长的激光焊接Ti/Cu异种金属结构存在极大的难度。使用不同波长和多波长复合的激光对TC4钛合金/T2纯铜进行焊接试验,研究激光波长对焊缝结构和性能的影响,并使用3D表面轮廓扫描分析仪、扫描电镜(SEM)、能谱仪(EDS)和X射线衍射仪(XRD)等设备对焊缝表面形貌和界面显微组织开展评价分析。结果表明:蓝光促进了Cu对激光能量的吸收,使焊缝的结构成型更优。在复合光源偏置光斑的最优焊接参数条件下,获得了最高拉伸强度为204.51 MPa的接头,其平均拉伸强度(196.82 MPa)达到T2 Cu母材(230 MPa)的85.57%。界面分析表明,最优参数下的Cu侧的熔化大于Ti侧,焊缝中以Cu元素为主,仅形成了由Ti扩散导致的12μm厚的金属间化合物层。拉伸断口分析表明,Ti_(2)Cu,TiCu和TiCu_(2)等金属间化合物是影响接头力学性能的主要原因。研究所发现的现象对提升Ti/Cu异种金属激光焊工艺的开发及工业化应用具有重要意义。Ti/Cu dissimilar metal structure can combine the advantages of both materials and meet the needs of low density,high specific strength and high thermal conductivity of the structure,which has a broad application in automotive,aerospace and other fields.However,due to the huge physical and chemical differences between Ti and Cu,the hard and brittle Ti-Cu intermetallic compound(IMC)layer is easily formed at the interface of the weld,which seriously affects the mechanical properties of the weld.Using laser welding with high energy density to achieve precise control of the melting amount of both materials is an effective way to reduce IMC at the weld interface.But then,due to the high reflectivity of Cu to conventional near-infra-red(NIR)laser,the high laser energy input is required to generate the keyhole on Cu side and bring the weld into deep fusion mode,which greatly wastes laser energy.At the same time,high power input also makes the keyhole behavior in deep fusion mode uncontrollable,and it is difficult to achieve precise regulation of the melting amount on both sides.In recent years,the emergence of high-power blue lasers has provided the conditions for solving this problem.The absorption rate of Cu for blue light with a wavelength of 455 nm is more than 60%,which is much higher than the absorption rate of 5%for near-infrared light with a wavelength of 1080 nm.Therefore,in this study,laser offset welding of TC4 titanium alloy/T2 copper was carried out with NIR light,blue light,NIR light+blue light source with a total power of 1000 W.The surface morphology,interface microstructure,Vickers hardness and room temperature tensile properties of the obtained welds were analyzed systematically.The results showed that blue light promoted the absorption of laser energy by Cu material,resulting in better weld formation.Under the conditions of 1000 W NIR light and offset laser spot,the welded joint was not successfully obtained.Under the conditions of 1000 W near-infrared light and non-offset laser spot,although the weld

关 键 词：Ti/Cu异种金属 复合激光焊接 近红外(NIR)激光 蓝光激光 

分 类 号：TG456.7[金属学及工艺—焊接]