Effect of heat treatment on microstructure and properties of single crystal copper cold-welded joints

With the means of electron backscattered diffraction (EBSD), mechanical properties test and digital eddy current metal conductivity, the single crystal copper cold- welded joint was tested and analyzed, the structure change of cold- welded joint and the effect of heat treating on the structure and property of cold- welded joint were discussed. The results show that: The deformation area of the single crystal copper cold welded joint is broken, the crystalline grain at the interface of the joint is refined, and the single crystal structure is still maintained in the base metal area. The hardness of the deformation area increases greatly, the conductivity of the joint does not change much, and the tensile strength of the joint reaches about 70% of that of the base metal. At the interface of the heat treating joint, the single crystal structure of the deformation area and the base metal area are destroyed, and the grains grow up at the interface and the orientation is different. The hardness of the joint interface is much lower than that of the non-heat treating joint, the electrical conductivity of the joint is good, and the tensile strength of the joint is higher than that of the base metal.