Feasibility of a laser powder bed fusion process for additive manufacturing of hybrid structures using aluminum-titanium powder-substrate pairings

The state of the art in the thermal joining of aluminum and titanium sheets in butt or overlap joint configuration specifies that the titanium should remain in the solid state to limit the formation of a brittle intermetallic compound layer in the interface. In this study, aluminum samples were additively manufactured onto titanium substrates and vice versa titanium samples onto aluminum substrates using a standard commercial laser powder bed fusion 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 tensile strength are analyzed. Despite the melting of both materials, a great potential for high interfacial tensile strength has been found for laser fusion of titanium powder on aluminum substrates.