5383铝合金电子束焊接接头组织与性能研究

Study on Microstructures and Properties of 5383 Aluminum Alloy Joint by Electron Beam Welding

通过金相观察、力学性能试验和SEM技术研究了5383铝合金真空电子束焊接接头的金相组织、力学性能和断口形貌特征。结果表明,焊接接头的拉伸强度低于母材;焊缝区组织主要为基体上均匀散布的强化相,熔合区为柱状树枝晶;在焊缝熔合线附近由于一次枝晶的生长方向受凝固过程中温度梯度的影响,微观组织为垂直于熔合线方向的柱状树枝晶;焊接接头的拉伸断口呈韧窝特征,但底部易出现气孔缺陷,单纯采用扫描函数不能完全消除根部气孔缺陷。

The metallurgical structures,mechanical properties and fractographs of electron beam welded 5383 aluminum alloy joint were studied by means of metallography observing,mechanical test and SEM technology. The results showed that the tensile strength of the joint was lower than that of base metal. The fractographs of the tensile specimens had dimple surfaces. The crystallizing morphology on the weld metal zone was equiaxed the strengthening phase evenly distributed in the substrate,and that on the fusion area were columnar dendrites. Due to the primary dendrite around the bond line affected by the temperature gradient in the solidification process,columnar dendrit perpendicular to the bond line featured the microstructure near the bond line. Scanning function was tried to eliminate porosity deflect,which had a high chance to form in the root of the weld,but scanning function alone couldn＇t eliminate the deflect completely.