焊接材料对7075铝合金焊接性及焊缝组织的影响

摘要

为了改善7075铝合金的焊接性并提高焊接接头的力学性能,采用ER4043和ER5356焊丝对7075铝合金进行了焊接.利用万能拉伸试验机和小型维氏硬度计对焊接接头的力学性能进行了检测,利用金相显微镜、扫描电子显微镜、能谱仪和X射线衍射仪观察并分析了焊接接头的显微组织.结果表明,由ER5356焊丝焊接得到的焊接接头的力学性能高于采用ER4043焊丝的性能.与ER4043焊丝焊缝相比,ER5356焊丝焊缝的晶粒组织较为细小,析出相分布也更加均匀.ER5356焊丝中的Mg元素有利于提高焊接接头的强度,而ER4043焊丝中的Si元素有利于提高7075铝合金的焊接性.%In order to improve the weldability of 7075 aluminum alloy and enhance the mechanical properties of welded joint,the 7075 aluminum alloy was welded with ER4043 and ER5356 welding wires. In addition,the mechanical properties of welded joint were tested with both universal tensile testing machine and small Vickers hardness tester,and the microstructure of welded joint was characterized with the optical microscope(OM), scanning electron microscope(SEM), energy dispersive spectrometer(EDS) and X ray diffractometer(XRD). The results show that the mechanical properties of welded joint obtained with ER5356 welding wire is higher than those of welded joint obtained with ER4043 welding wire. Compared with the weld bead with adopting ER4043 welding wire,the grain in the weld bead with adopting ER5356 welding wire is finer, and the distribution of precipitates is more uniform. The Mg element in ER5356 welding wire is beneficial to enhancing the strength of welded joint, while the Si element in ER4043 welding wire is beneficial to improving the weldability of 7075 aluminum alloy.