Effect of microelement on contact-reaction brazing of 6063 aluminum alloy

The 6063 Al alloy joint using Cu cladding as reaction layer was obtained by contact-reaction brazing method. The typical interfacial structure of the joint was analyzed,and also the effect of microelement on interface structure and joint strength were emphasized. The results show that the brazing interface consists of Al₂Cu,α-Al,Mg₂Si and ω-Fe₁Cu₂Al₇,the existence of Fe results in formation of ω-Fe₁Cu₂Al₇ lath-shaped phase and weakens the joint shearing strength,and Mg and Si elements enriches in the center of brazing seam as Mg₂Si phase and exacerbates with the extension of holding time. The shearing strength of the joint is mainly controlled by the category and feature of interfacial products and the extent of isothermal solidification,and the highest average shearing strength of the joint can reach 105.3 MPa at brazing temperature of 570℃ and holding for 60 min.