Unveiling the potential of multimaterial laser-based powder bed fusion processes: a novel approach for enhancing design freedom in multimaterial additive manufacturing

Laser-based powder bed fusion of metallic materials (PBF-LB/M) is particularly suitable to produce complex components. The increasing demands regarding the performance of safety-related components and locally separated requirements within these are currently a major concern for manufacturing companies. Multimaterial powder bed-based Additive Manufacturing (MMAM) approaches are associated with cross-contamination and limited in-situ alloying due to a global material handling. This is accompanied by increased requirements for the facility systems for the deposition of various materials. A new machine concept combining the PBF-LB/M with a dispensing system has been developed to enable the production of graded and discrete intra- and inter-layer interfaces without joints in a single-stage process. Here, the combination of Inconel 718 (IN718) parts with locally applied copper (Cu) structures is reported, whereby discrete interlayer interfaces can be realized. The production of graded intra- and interlayer interfaces by simultaneously changing the proportions of IN718 and Cu is also investigated. In this work, we examined the influence of the process parameters of a dispensing unit for material application and a volumetric powder delivery device which is connected to the dispensing unit and allows in-situ-alloying. The influence of the subsequent fusion step on the structural properties of the interfaces was studied as well. Through this work, it is shown that the new machine concept enhances the design freedom of the PBF-LB/M process in the context of multimaterial processing. The production of discrete and graded intra- and interlayer interfaces is demonstrated using EDX measurement. Due to the different approach to material application, structures with differing properties are produced. Higher component densities can be achieved when copper is applied in a global IN718 powder bed (87% for the copper areas and 82% for IN718 areas). If the global material application is replaced by the dispensing system instead, a lower dimensional accuracy and a high error rate of 37 % can be observed.