Microstructure Characteristics And Mechanical Properties Of Cold Metal Transfer Welding T2/A11060 Dissimilar Metals

Weldability of dissimilar metal between T2 and A11060 was researched through CMT. Overlap welding was tried with S301, ER4043, ER4047 as welding wire to get welded joint under different welding conditions. The phase and morphology of the welded joints were observed and tested, the influence of heat input to the weld microstructure, mechanical properties and fracture characteristics were studied, testing weld mechanical properties of joints and discussing the factors that affect the thickness of the weld metal compounds. The method about how to improve the welded joints strength was studied, especially though the way of nickeling.Metallographic microscope, SEM, EDS and XRD were used to analyze the microstructure of the welded joints. The results show that while using the wire S301, the welded joints generated a layer of dense intermetallic compound, the main component is CuAl2, Cu3Al2, CuAl and the copper solid solution in aluminum; While using the wire ER4043, the welded joints also generated a layer of dense intermetallic compound; the main component is CuAl2、CuAl3、CuAl4 and the copper solid solution in aluminum; While using the wire ER4047, the welded joints generated a layer of complicated intermetallic compound, the main component is CuAl2, CuAl, Cu3Al4, CuAl4 and the copper solid solution in aluminum. After the surface of copper plate adopt nickel plating, the main component of welded joints is CuAl4 and Cu3Al. The layer of Ni can block the spread of dissimilar metals.The hardness of the base metal on both sides uniformed distribution. Due to producing intermetallic compounds at the weld bond, a sharp increase in the hardness appeared, this kind of phenomenon...