Laser powder bed fusion (PBF-LB) has established itself as an industrial process for the manufacturing of complex metal parts for lightweight applications. The increasing prevalence of PBF-LB parts, as well as the increasing functional integration and size limitations of PBF-LB machines are leading to a growing demand for joining processes for PBF-LB parts.


However, one limitation for laser welding of PBF-parts, especially aluminum parts, are porous weld seams with volatile mechanical properties. Therefore, this work investigates the impact of the PBF-LB process parameters and the resulting part properties on the overall weld seam quality of laser-welded AlSi10Mg PBF parts.


In a first step PBF-LB specimens with different porosities regarding relative density, pore shape and pore size were manufactured with experimentally defined process parameters. Subsequently specimens were laser welded in three different configurations (lap joint, butt joint and bead on plate welding). Cross-sections of the weld seams were metallographically prepared to investigate the overall porosity and pore sizes as well as the local pore distribution and local hardness deviations in the weld seam. Tensile tests were carried out to assess the impact on the load bearing capacity of the weld seam. Similar experiments were done using conventional aluminum cast and sheet material and results were compared.


The investigation showed that the weld seam porosity of laser-welded AlSi10Mg PBF-parts is significantly higher compared to conventional aluminum materials, but does not depend on the initial porosity of the joined PBF-parts, but rather on the PBF process parameters and the resulting microstructure.