Hybrid additive manufacturing with titanium powder and aluminum substrates via laser powder bed fusion

For the thermal joining of aluminum and titanium, the approach of solely melting the aluminum joining partner, while the titanium partner stays in the solid form, has been commonplace since 1996. This is done to limit the formation of a brittle intermetallic compound layer in the interface. In case of additive manufacturing with titanium powder and aluminum substrates, this approach is not transferrable because the titanium powder has to be melted to create the part. In this study, titanium samples were additively manufactured onto aluminum substrates using a commercial laser powder bed fusion (LPBF) machine. The influences of the energy density during the process on the sample porosity, the characteristics of the interface between sample and substrate, as well as the interfacial tensile strength are analyzed. Despite the melting of both materials, a great potential for high interfacial tensile strength has been found.