2024铝合金与T2紫铜的搅拌摩擦焊接头组织及力学性能

Microstructures and mechanical properties of 2024 aluminum alloy and T2 copper friction stir welding joints

针对板厚均为3 mm的2024铝合金和T2紫铜异种金属进行了搅拌摩擦焊接。采用光学显微镜、扫描电镜和透射电镜对接头组织和铝-铜界面进行观察分析,并进行了显微硬度和拉伸性能测试。结果表明,接头表面成形优异,无宏观缺陷,焊核区形成了明显的洋葱环结构,洋葱环由层片状铝和颗粒形式分布的铜组成;在铝-铜界面形成了一层厚度约0. 98μm的金属间化合物层。在转速为800 r/min、焊接速度为50 mm/min的焊接参数下得到了力学性能优异的接头,接头平均抗拉强度为158 MPa,强度与母材铜相当,平均断后伸长率为10%,为母材铝的87%,拉伸断裂于铜侧母材,断裂方式为韧性断裂。

2024 aluminum alloy and T2 copper dissimilar metal joints with the thickness of 3 mm were successfully fabricated by friction stir welding.Optical microscope,scanning electron microscope and transmission electron microscope were used to observe the microstructures of joint and interface of the Al-Cu joint.Micro-hardness and tensile properties of the joint were tested.The results showed that the top surface of the joint was excellent without macroscopic defects,and the onion ring structure formed in the weld zone.The onion ring is composed of lamellar aluminum and particles of copper.The thickness of the intermetallic layer formed at the Al-Cu interface was about 0.98μm.The joints with excellent mechanical properties were obtained at the rotational speed of 800 r/min and welding speed of 50 mm/min.The average tensile strength of the joint was 158 MPa which was comparable to that of the Cu base metal.And the average elongation of the joint was 10%which come up to 87%of the aluminum base metal.The tensile fracture occurred at the base metal of copper side and the fracture mode was ductile.