Hybrid technology for additive manufactured (AM) components made from AlSi10Mg
Powder bed-based additive manufacturing processes such as selective laser beam melting (SLM) are particularly well suited for the production of geometrically complex functional metal components. In comparison to conventional manufacturing processes, however, the size of the components that can be produced is not only limited technically by the volume of the construction chamber, but also by economically factors due to the low build-up rates.
By providing a reliable welding technology, additive manufactured components can be joined to conventional structures at the exact location where the associated higher complexity or functionality is necessary for the application, thus reducing costs and/or increasing the application spectrum of AM components. Therefore, this study investigates the production of mixed joints from AlSi10Mg material by electron beam welding (EBW). The AM material used was produced by selective laser melting, whereas the conventional material was produced by die casting (DC) and continuous casting (CC).
It is already known that EB welding of SLM-processed aluminium in deep welding modes results in the distinctive formation of pores in the manufactured weld seams, and that pore-free weld seams can only be produced by changing from the keyhole welding mode to heat conduction welding. These results could be confirmed by the investigations, which is why two different joining strategies were investigated to reduce porosity in the welding zone. The welded joints produced were characterized by ultrasonic testing, metallographic investigation of cross sections, hardness measurements and micro-tensile tests. While a beam offset did not lead to a significant reduction in weld porosity, a multi-bath welding process and the configuration of selected welding parameters could produce seams of sufficient quality. The investigations proved the applicability of the EB keyhole welding mode in electron beam welding for the production of low-porosity SLM mixed joints.