Interfacial reaction and microstructure evolution of nanoparticle-added Al/Cu welded interface under direct current treatment

The 1060 pure aluminum was joined to T2 copper in the lap configuration by plasma arc welding with adding nanoparticles, and the welded joint was treated by direct current (DC). The DC current loading experiment was carried out on the welded joint, the change of the interface structure of the joint under the DC electric field was studied, and the evolution mechanism of the interface intermetallic compound (IMC) under the current loading was analyzed. The results found that in the DC electric field, the electron wind, temperature gradient and concentration gradient during the electromigration process promoted the migration of Al and Cu atoms, and the increase of the joint temperature during the welding process promoted the atomic reaction. With the prolon-gation of the current loading time, the thickness of the intermetallic compound layer at the interface of the joint increases to different degrees. At the same time, the nanoparticles are also aggregated into large-sized grains under the action of the electric field, which are distributed in the Al-Cu eutectic zone at the front of the compound.