高差异性异种金属材料磁脉冲焊接界面行为与结合机理

Joining of dissimilar materials of High-Discrepancy （primarily in hardness hard and soft metal）has a broad and significant application prospects in aerospace and automobile industry. The interfacial behavior of magnetic pulse welded joints of such dissimilar metal match is different from the wavy bonding of those of Low-Discrepancy. Based on the flyer plate impact model, the interfacial behavior of the joints is the result of the interaction between the elastic vibration of the hard baseboard and the viscoplastic waving of the soft flyer plate. The high speed camera and the laser Doppler velocimeter are adopted to analysis the transient deformation of the flyer plate under high speed impact; Laser scanning confocal microscopy is used to observe the microstructure morphology of the interface of the dissimilar materials and the distribution of non-equilibrium intermetallic phase (IMP). The electron backscatter diffraction (EBSD) method is used to analyze the grain orientation and misorientation of the bonded area, and to explore the interface transient behavior of the elastic vibration and viscoplastic wave. Interacting mechanisms between the vibration and wave are systematically studied to explore the electromagnetical and mechanical conversion and transmission mechanism during the high-dynamic welding process and thus reveal the nonstationary oscillation and bonding mechanism in the magnetic pulse welded interface of dissimilar metal materials with High-Discrepancy. These fundamental and scientific efforts are expected to enable effective control the formation and distribution of intermetallic compounds in the bonding interface, and final and to optimization the geometry and electrical parameters in magnetic pulse welding process.

异种金属材料连接在航空航天、汽车领域有广阔应用前景，高差异性异种金属磁脉冲焊接接头的界面行为不同于物性相近金属材料的波状结合。依据飞板冲击模型，其界面行为是硬基板的弹性振荡与软飞板的粘塑性波动交互作用的结果。本课题采用高速摄像与激光多普勒测速技术相结合记录、分析高速撞击条件下飞板的瞬态变形过程，采用激光共聚焦显微分析技术观察异种材料界面的微观组织形貌和非平衡结晶的中间相（IMP）的分布形态，采用EBSD技术分析冲击前后的界面及基体的晶粒取向和取向差，探究界面的弹性振动和粘塑性波动的瞬态行为。研究高差异性异种材料磁脉冲接头界面的振动与波动的交互作用机制，探寻电、磁、力、热的转换与传递机制，揭示高差异性异种金属材料磁脉冲焊接界面非稳态振荡结合机理，进而控制结合界面金属间化合物的形成及分布规律，明确高差异性异种金属材料磁脉冲焊接结合机制，并得到其几何和电参数设计规范。

中小直径管件异种金属材料连接在航空航天、汽车领域有广阔应用前景。但是异种金属的常规熔化焊接方法形成的接头性能不足，开展异种材料管件的新型连接技术研究已迫在眉睫。本项目围绕“高差异性异种金属材料磁脉冲焊接界面行为与结合机理”展开，建立了电磁脉冲焊接模型，探明了待焊管件在不同时刻、不同电压、不同周向位置下所受的磁感应强度分布规律，揭示了电磁脉冲焊接过程中待焊管件各部位的受力情况，并通过空管变形实验以验证仿真结果的准确性；通过分析不同重叠长度下硬基板与软飞板连接界面的形貌变化，结合面微观形貌与力学性能的变化规律定义了焊接过程中三种不同冲击模式，探明焊接过程中硬基板与软飞板的交互作用与焊接冲击模式的变化规律；分析驱动飞板加速能量构成及能量转换规律来提高能量转换效率，提高接头性能；通过结合面微观表征探明了不同工艺参数下、不同接头位置的界面过渡层中间相分布规律，结合力学性能实验揭示了异种材料界面过渡层中间相对接头连接强度的影响规律；研究了结合面中不同过渡层形貌变化规律，探明了过渡层中金属间化合物成分及过渡层产生原因，揭示了界面及基体微观组织演变规律。本项目的研究成果将为获得优质的高差异性异种金属材料焊接接头提供理论支撑和科学依据。