电子束工艺对7075/TA1异种金属焊接接头组织性能的影响

Effect of Electron Beam Process on Microstructure and Properties of 7075/TA1 Dissimilar Metal Welded Joint

采用传统电子束焊接和电子束扫描焊接方法对7075铝合金和TA1钛合金进行了对接焊接,对比分析了两种电子束技术对异种金属焊接接头显微组织、硬度和拉伸性能的影响。试验结果表明,相较于传统电子束焊接,电子束扫描焊接会增加7075铝合金侧焊缝宽度,减小TA1钛合金侧焊缝宽度,且电子束扫描焊接的异种金属焊缝区过渡更加平滑。电子束扫描焊接铝合金侧热影响区明显更窄,且焊缝区等轴晶晶粒尺寸更加细小。传统电子束焊接界面区上部有明显钛合金溶于铝合金焊缝的特征,界面结合处呈不规则形状,局部区域可见长条状、岛状和棒状组织,而电子束扫描焊接界面区上部界面结合处呈规则弧形,未发现有钛合金溶入铝合金焊缝的特征。电子束扫描焊接接头的焊缝区和界面区硬度低于传统电子束焊接接头的,抗拉强度和断后伸长率都高于传统电子束焊接的。

7075 aluminum alloy and TA1 titanium alloy were butt welded by traditional electron beam welding and electron beam scanning welding. The effects of two electron beam technologies on the microstructure, hardness and tensile properties of dissimilar metal welded joints were analyzed. The experimental results show that, compared with the traditional electron beam welding, the electron beam scanning welding can increase the weld width of 7075 aluminum alloy side, reduce the weld width of TA1 titanium alloy side, and the transition of dissimilar metal weld area is more smooth;the heat affected area of aluminum alloy side is significantly narrower, and the equiaxed grain size of weld area is smaller;there are obvious features of titanium alloy dissolving in weld of aluminum alloy in the upper part of the interface area of traditional electron beam welding, the joint interface is irregular shape, and long strip, island and rod structure can be seen in the local area. While the joint of upper interface area of electron beam scanning welding is regular arc, and no feature of titanium alloy dissolving in the weld of aluminum alloy is found. The hardness of the weld area and interface area of the electron beam scanning welded joint is lower than that of traditional electron beam welding, and the tensile strength and elongation of the electron beam scanning welded joint are higher than those of traditional electron beam welding.