The application of aluminum alloys offers significant specific weiqht saving potentials in the automotive industry and in some areas of the transport sector. At present, the aluminium alloys relevant for application are not easy to weld or the thermal input leads to a decrease of the strength in the heat affected zone. Therefore, a new approach was evaluated to develop aluminium-based braze alloys to meet the various demands for brazing processes and brazed joints. Application oriented demands for brazes are low processing temperature, good wetting behaviour, desirable mechanical properties concerning strength, fatigue and ductility and application specific properties e.g. corrosion resistance, low surface roughness. Based on these requirements, new brazing alloys based on the alloying system Al/Si were developed. Additional alloying elements are Cu, Sn, Mg and Ag [StoO4]. Starting from a near eutectic Al/Si composition, selected for good cold forming behaviour, the alloying elements were mainly added to decrease the melting temperature and melting interval. The processability of the newly developed braze alloys with low melting point by plasma-arc-brazing was proven. The alloys were successfully used for brazing overlap joints of AA 6016T4 with a thickness of 1.5 mm. The braze alloys showed generably good to sufficient wetting behaviour. Best wetting behaviour was found for the silver containing alloy. Additionabby, highest tensile strength values were obtained for joints prepared using alloy BA3 (Al10SiCuAg) while the hardness values were close to the base material. However, the alloy BA6 (Al10Si6CuSnMg) without silver reveals also good tensile strength values. Compared to BA3, braze alloy BA6 showed an inferior wetting behaviour and the amount of porosity within the braze seam was significantly higher. Under the assumption that both, wetting behaviour and pore formation, are mainly determined by the high affinity of magnesium to environmental gases, the prevention of these effects should be realized by further process improvement.


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    Title :

    Plasma-brazing of Al-alloys using new brazing alloys for high strength joints


    Contributors:
    Wagner, F. (author) / Kreimeyer, M. (author) / Schubert, E. (author) / Vollertsen, F. (author)


    Publication date :

    2004


    Size :

    9 Seiten, 7 Bilder, 2 Tabellen, 4 Quellen


    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




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