3A21铝合金-20钢管磁脉冲连接实验研究

利用低电感线圈磁脉冲连接(MPJ)装置, 研究了放电电压、管件径向间隙和搭接区长度对3A21铝合金-20钢管连接接头拉伸和剥离力学性能的影响. 通过SEM进行了接头界面的微观形貌观察和元素分布的EDS分析. 结果表明, 随放电电压提高, MPJ性质由机械连接向冶金连接转变. 在放电电压为5.5 kV、径向间隙为1.5 mm、搭接区为3/4线圈长度条件下, 获得界面呈小波纹状、Al和Fe元素发生互扩散的冶金接头. 与接头界面临近的基体金属发生了剧烈 塑性变形和晶粒细化.

EXPERIMENTAL RESEARCH ON MAGNETIC PULSE JOINING OF 3A21 ALUMINUM ALLOY-20 STEEL TUBES

Magnetic pulse joining (MPJ) is a solid state joining technology, by which mechanical or metallurgical joint is obtained. It can be used to assemble and join dissimilar metals. In this work, by means of MPJ setup with low inductance coil, the effects of discharge voltage, radial gap between tubes and lap length on the tensile and peel testing strength of 3A21 aluminum alloy-20 steel tubes joint were investigated experimentally. The microstructural observation and the energy spectrum analysis (by linear scan) of basic elements distribution within the MPJ joint interface were performed by SEM. The results showed that an increasing discharge voltage contributed to the change of MPJ joint from mechanical joint to metallurgical one. The metallurgical joint with the small wave joining interface was obtained under a voltage of 5.5 kV, a radial gap of 1.5 mm, and a lap length of 3/4 coil length, where the mutual diffusion of Al and Fe elements occurred. The severe plastic deformation with sharp strain gradient, and the distinct grain refinement occurred in the matrix metals near the joining interface.