Al-Zn-Mg-Cu合金搅拌摩擦焊接头的显微组织与力学性能

Microstructure and Mechanical Properties of Friction Stir Welded Joint of Al-Zn-Mg-Cu Alloy

采用光学显微镜、维氏硬度仪和拉伸试验机,研究了Al-6. 6Zn-1. 7Mg-0. 26Cu合金挤压材搅拌摩擦焊接头的显微组织和力学性能。结果表明,搅拌摩擦焊接头的焊缝组织为细小均匀的等轴晶粒,接头的硬度以焊缝为中心呈W形状对称分布,焊缝硬度值在107HV～115HV之间,从焊缝中到母材,硬度先下降再上升,回撤侧热影响区的硬度值最低为104HV,前进侧热影响区的硬度值最低为102HV。接头的抗拉强度为404. 3 MPa,屈服强度为265. 9MPa,延伸率为18. 1%,接头的焊接强度系数为0. 96。

In this paper, the microstructure and mechanical properties of friction stir welded joint of Al-6.6 Zn-1.7 Mg-0.26 Cu alloy are studied by optical microscope, vivtorinox hardness tester and tensile testing machine. The results show that the microstructure of the friction stir welded joint is fine and uniform equiaxial crystal grain and hardness value of the welded joint is symmetrically distributed at the center of the welded joint with the shape of W. The hardness value of the welded seam is between 107 HV - 115HV and it first descends and then rises from the welded seam to the base material. The hardness value of the heat affected zone near the retracting side is lowest to 104HV and the heat affected zone near the forward side is lowest to 102HV. The tensile strength of the welded joint is 404.3 MPa, the yield strength is 265.9 MPa, the elongation is 18.1%, the welding strength coefficient is 0.96.