Microstructure and Mechanical Property of 3003 Aluminum Alloy Joint Brazed with Al-Si-Cu-Zn Filler Metal

Abstract

Al-Si-Cu-Zn filler metal was developed to braze 3003 aluminum alloy. The microstructure and fracture surface of the joint were analyzed by XRD, SEM and EDS, and the effects of brazing temperature on microstructure and property of the joint were investigated. The results show that good joints are obtained at brazing temperature of 540-580℃ for 10min. The brazed joint consists of α(Al) solid solution, θ(Al2Cu) intermetallic compound, fine silicon phase and AlCuFeMn+Si phase in the central zone of brazed seam, and α(Al) solid solution and element diffusion layers at both the sides of brazed seam, and the base metal. The room temperature (RT) shear fracture of the joint occurs at the interface between the teeth shape α(Al) in the diffusion layer and the center zone of brazed seam, which is mainly characterized as brittle cleavage. As the brazing temperature increases, α(Al) solid solution crystals in the diffusion zone grow up, and the interfacial bonding of the joint is in the form of interdigitation. Brazing at 560℃ for 10min, the RT shear strength of the joint reaches the maximum value of 92.3MPa, which is about 62.7% of the base material.

Keywords

• aluminum alloy
• brazing
• aluminum based filler metal
• joint microstructure