Research On Corrosion Resistant Aluminum Alloy With Low Melting Point

The brazing of6000series aluminum alloy has been the focus of research at homeand abroad, due to the lack of low melting point solders with good overall performance,the softening of parent material after brazing has not been properly solved. Took binaryand ternary phase diagrams of Aluminum and Aluminum alloy for reference, orthogonalexperimental design method had been used in this paper. The right amount of Copper,Nickel and Tin were added in Al-Si alloy as the object of study, constitutingAl-Cu-Si-Ni-Sn Aluminum alloy solder. By analyzing the influence of the addedelements on the solder performance, ensuring the sufficient strength of the joints ofAluminum alloy, as well as good resistance to atmospheric corrosion.There’s a great effect of Silicon and Copper elements on liquidus temperature ofsolder, the addition of Silicon and Copper will reduce the melting point obviously. Withincreasing content of alloying elements, non-congruent melting gradually changed intocongruent melting, and thus reduced the melting temperature range. The addition of Tinmay significantly reduced its corrosion resistance, while Nickel will increase thecorrosion resistance and mechanical properties of the solder, the suitable mass fractionis about2%.The microstructure analysis of the solder showed that, the alloy is mainly composedby α (Al) phase, θ (CuAl2) and blocky primary Silicon phase. The addition of Nickelinduces the grain refinement effect, which can improve the corrosion resistance andmechanical properties of the solder, the mass fraction of about2%is appropriate; Theaddition of Copper will increase the quantity of brittle θ (CuAl2) phase and Al6Cu3Niphase.Considering the liquidus temperature of solders, corrosion resistance and mechanicalproperties, the sample of Al-10Si-20Cu-1Ni and Al-12Si-12Cu-2Ni in this experimentare best, with lower melting point, narrower melting temperature range, better corrosionresistance and the higher characteristic of joint, can be applied to vacuum brazing of6063aluminum alloy, and be promoted in the industrial field basically with lower price.