Al-Mg合金电子束填丝焊接头的显微组织与力学性能

采用ER5183焊丝作为填充材料,对厚度为2 mm的Al-Mg合金进行真空电子束填丝焊接,并对焊接接头的微观组织及力学性能进行分析测试。结果表明,在合适的焊接工艺条件下,获得的Al-Mg合金接头焊缝成形良好。微观分析显示,接头熔合区为柱状晶和等轴状枝晶组织,主要由α(Al)基体相和β(Al₃Mg₂)强化相组成,焊缝中存在大量的缠结位错和第二相粒子。力学性能测试表明,与母材区的硬度相比,接头熔合区的硬度有所降低。在最佳工艺条件下获得接头的抗拉强度为311.2 MPa,达母材抗拉强度的96.9%。接头拉伸断口表面分布的韧窝数量较多,呈明显的韧性断裂特征。

Microstructure and Mechanical Property of Al-Mg Alloy Joint by Electron Beam Welding with Filler Wire

The 2 mm thick Al-Mg alloy plate is welded by vacuum electron beam welding with ER5183 filler wire, and the microstructure and mechanical property of the welded joint are analyzed and tested. The results show that, with the suitable welding technique, the Al-Mg alloy joint with good appearance of weld can be obtained. Microstructure analysis shows that the fusion zone (FZ) is composed of columnar crystal and equiaxed dendrite, which are mainly α(Al) matrix and β(Al₃Mg₂) strengthening phases. There exist lots of entangled dislocations and secondary phase particles in the weld line. The hardness in FZ decreases to a certain extent compared with that of the base metal (BM). The tensile strength of the joint by the optimized welding parameters is 311.2 MPa, which is 96.9% of that of the BM. There are many dimples on the tensile fracture surface of the joint, and the ductile feature is obvious.