2012 Volume 53 Issue 9 Pages 1638-1643
Ternary Al–Si–Zn filler metals were designed in order to join the 6061 aluminum alloy. The microstructure, phase constitution and fracture morphology of the brazed joint were investigated. Results of the microstructure observation showed that eutectoid α(Al) + η(Zn), α(Al) solid solution, as well as Si particles formed in the filler metal. The melting points of these filler metals are much lower than Al–12Si alloy. The η(Zn), α(Al) solid solution, and the primary Si particles were found in the 6061 Al brazing seam when using Al–0.2Si–78Zn and Al–2Si–62Zn filler metal, while the Al–Si eutectic were found when using Al–6.5Si–42Zn alloy. Results also indicate that the tensile strength of the 6061 Al brazed joints using Al–0.2Si–78Zn, Al–2Si–62Zn and Al–6.5Si–42Zn is 101, 109, 129 MPa, respectively. The fracture morphology of the brazed joints showed intergranular fracture mode while some transgranular fracture could be found in the joint of Al–6.5Si–42Zn filler metal.