Ghazal Moeini, Mohamed Merghany, Joerg Vogelsang, Seyed Vahid Sajadifar, Jochen Tenkamp, Thomas Niendorf, Frank Walther

• Abstract Laser-based powder bed fusion of metals (PBF-LB/M) is found to be a promising processing method for the fabrication of components with no limits of complexity by adding layers upon layers of material. However, drawbacks such as pro- ductivity and dimension limitations adversely affect the employment of com- ponents processed by additive manufacturing (AM) in envisaged applications. This brings welding and joining techniques into play to integrate AM metal parts into larger assemblies. In the present study, electron beam welding is used to join the AlSi10Mg specimens, fabricated via two different manufacturing processes, that is, PBF-LB/M and casting. The main focus is to study the quasistatic and fatigue behavior of similar and dissimilar welded joints in different combinations, namely AM–AM, AM–cast, and cast–cast, alongside thorough microstructure analysis, to investigate the correlation between the microscopic and macroscopic properties. Dissimilar welded joints demonstrate inferior material strength. This fact can be attributed to the inherent coarse microstructure of the cast material. Although similar welded joints of AM components suffer from high porosity in the weld zone, they are characterized by a better fatigue life, which can be attributed to the equiaxed eutectic microstructure in the welded area.