Brazing of 6061 aluminum alloy with the novel Al-Si-Ge-Zn filler metal

Abstract

The novel Al-Si-Ge-Zn filler metal was used for brazing 6061 aluminum alloy. Microstructure and properties of the filler metal and brazed joint were studied. The results showed that the main phases in the Al-Si-Ge-Zn filler metal as well as the brazed seam were α-Al, β-GeSi, and η-Zn phases. Compared with the common Al-Si-Ge and Al-Si-Zn filler metals, it had smaller and better dispersive β-GeSi solid solution phases without coarse primary Si phase. The melting temperature of Al-Si-Ge-Zn filler metal is 505.2~545.1°C, and the narrow melting temperature interval is favorable for the brazing process. When this filler metal was used to braze the 6061 aluminum alloy, an optimized shear strength of 138.2MPa was achieved. Observation of the fracture section showed that the brazed joints presented obvious ductile fracture characteristics.