摘要
锆/镍异种金属焊接结构在现代工业应用中日益广泛,但因母材热物理和化学性能存在较大差异,导致焊接难度大。超声波焊接作为一种固态连接工艺适应于异种金属焊接。研究不同焊接能量对锆/镍异质金属超声波焊接金属间化合物(IMCs)生长行为与机械性能的影响机制。以锆箔、镍箔为原材料,采用焊接功率1600 W,通过改变焊接时间300,～400,～500,～600 ms调控焊接能量设计异质金属超声波焊接试验。使用扫描电子显微镜(SEM)、能谱仪(EDS)、 X射线衍射(XRD)、 3D景深显微分析、显微硬度仪及拉剪强度测试等研究微观组织形貌、相结构、景深及显微硬度的变化规律,确定焊接能量与接头拉剪强度之间的定量关系,理解其连接机理和IMCs生长历程。结果表明:接头触点区无明显宏观裂纹等缺陷;随焊接能量增大,触点区原子互扩散层迅速增厚并趋于稳态,过厚的IMCs层诱导产生新的焊接缺陷;在焊接能量640 J时高应变率加速连接界面析出厚度约3.2μm的Ni_7Zr_2, Ni_(10)Zr_7和NiZr_2 IMCs相层,析出顺序为:Ni_(10)Zr_7, Ni_7Zr_2, NiZr_2;塑性变形在整个薄板厚度间传播,剧烈塑性变形促进了位错增殖,形成了由纳米晶和非晶相组成的过渡层;工件连接强度取决于机械互锁、纳米晶和非晶相过渡层与互扩散的综合作用。所获得的最优焊接工艺参数对提升接头力学性能和分析其界面组织变化具有重要意义。
Zr/Ni dissimilar metal welding structures have become more and more widely used in modern industrial applications.However,welding is difficult due to large differences with parent metal in thermal physical and chemical properties.Ultrasonic welding is a solid state joining process suitable for dissimilar metal welding.The influence mechanism of different welding energy on the intermetallic compounds(IMCs)growth behavior and mechanical properties of Zr/Ni dissimilar metal ultrasonic welding was investigated.Using zirconium foil and nickel foil as raw materials,welding power of 1600 W was adopted,and ultrasonic welding experiments for dissimilar metals were designed by changing welding time 300,~400,~500,~600 ms to regulate the welding energy.The scanning electron microscope(SEM),energy dispersive spectroscopy(EDS),X-ray diffraction(XRD),3D depth-of-field microscopic analysis,microhardness tester and tensile strength tester were used to study the variation of microstructure morphology,phase structure,depth of field and hardness,to determine the quantitative relationship between weld energy and tensile strength of the joint,and to understand the mechanism of connection and IMCs growth history.The results showed that there was no obvious macro crack and other defects in the joint contact area.As the welding energy increased,the atomic interdiffusion layer in the contact area rapidly thickened and tended to a steady state,and excessively thick IMCs induced new welding defects.When the welding energy was 640 J,high strain rates accelerated the precipitation of Ni7Zr2,Ni10Zr7 and NiZr2 IMCs phase at the interface,and its thickness was about 3.2μm.The precipitation order was Ni10Zr7,Ni7Zr2,NiZr2.The plastic deformation propagated throughout the thickness of the foil,and the severe plastic de-formation promoted the proliferation of dislocations.A transition layer consisting nanocrystalline and amorphous phases was formed.The strength of the workpiece connection depended on the combined effect of mechanical interlocking,t
作者
张义福
张华
朱政强
潘际銮
Zhang Yifu;Zhang Hua;Zhu Zhengqiang;Pein Jiluan(Key Laboratory for Robot & Welding Automation of Jiangxi Province,School of Mechanical & Electrical Engineering,Nanchang University,Nanchang 330031,China;School of Mechanics & Materials Engineering,Jiujiang University,Jiujiang 332005,China)
出处
《稀有金属》
EI
CAS
CSCD
北大核心
2019年第3期283-289,共7页
Chinese Journal of Rare Metals
基金
国家自然科学基金委员会-中国科学院天文联合基金项目(U1731118)
江西省轻质高强结构材料重点实验室开放基金项目(20171BCD40003)资助
