Abstract In this study, a novel friction-based welding technology was proposed for fabricating Al/Cu bimetallic tubes. The frictional heat and radial pressure during the friction-based welding process are used to achieve the metallurgical bonding between Al and Cu tubes in a rapid and efficient way. Successful joints indicate that this technology has the potential for fabricating bimetallic tubes. Microstructure evolution, bonding mechanism and mechanical properties of Al/Cu bimetallic tubes were also analyzed. Results reveal that columnar α-Al, intermediate transition layer and intermetallic compounds (IMC) are identified at the rotational speed of 950 rpm. While the rotational speed is decreased to 95 rpm, only solid-state diffusion occurs at the interface which results in three IMC layers, Al 2 Cu, AlCu, and Al 2 Cu 3 . The thickness of the Al 2 Cu is more significantly affected by the rotational speed than that of AlCu and Al 2 Cu 3 . Maximum hardness is observed at the reaction layer due to the formation of IMC. The appearance of intermediate transition and thick Al 2 Cu layer weakens the bonding strength of bimetallic tubes. The joints are fractured at the reaction layers, and the fracture exhibits typical brittle characteristic. Three crack propagation paths are observed at the interface of Al/Cu bimetallic tubes.

中文翻译：

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新型摩擦焊接技术制备的铝/铜双金属管的界面微观结构演变和力学性能

摘要 在本研究中，提出了一种用于制造铝/铜双金属管的新型摩擦焊接技术。利用摩擦焊接过程中的摩擦热和径向压力，以快速有效的方式实现铝管和铜管之间的冶金结合。成功的接头表明该技术具有制造双金属管的潜力。还分析了Al/Cu双金属管的显微组织演变、结合机制和力学性能。结果表明，在 950 rpm 的转速下识别出柱状 α-Al、中间过渡层和金属间化合物 (IMC)。当转速降低到 95 rpm 时，在界面处仅发生固态扩散，导致三个 IMC 层，Al 2 Cu、AlCu 和 Al 2 Cu 3 。与AlCu和Al 2 Cu 3 相比，Al 2 Cu 的厚度受转速的影响更大。由于 IMC 的形成，在反应层处观察到最大硬度。中间过渡和厚Al 2 Cu层的出现削弱了双金属管的结合强度。接头在反应层断裂，断裂表现出典型的脆性特征。在铝/铜双金属管的界面处观察到三种裂纹扩展路径。断口表现出典型的脆性特征。在铝/铜双金属管的界面处观察到三种裂纹扩展路径。断口表现出典型的脆性特征。在铝/铜双金属管的界面处观察到三种裂纹扩展路径。