Review on additive hybrid- and multi-material-manufacturing of metals by powder bed fusion: state of technology and development potential

Abstract

In this review paper, the authors investigate the state of technology for hybrid- and multi-material (MM) manufacturing of metals utilizing additive manufacturing, in particular powder bed fusion processes. The study consists of three parts, covering the material combinations, the MM deposition devices, and the implications in the process chain. The material analysis is clustered into 2D- and 3D-MM approaches. Based on the reviewed literature, the most utilized material combination is steel-copper, followed by fusing dissimilar steels. Second, the MM deposition devices are categorized into holohedral, nozzle-based as well as masked deposition concepts, and compared in terms of powder deposition rate, resolution, and manufacturing readiness level (MRL). As a third aspect, the implications in the process chain are investigated. Therefore, the design of MM parts and the data preparation for the production process are analyzed. Moreover, aspects for the reuse of powder and finalization of MM parts are discussed. Considering the design of MM parts, there are theoretical approaches, but specific parameter studies or use cases are not present in the literature. Principles for powder separation are identified for exemplary material combinations, but results for further finalization steps of MM parts have not been found. In conclusion, 3D-MM manufacturing has a MRL of 4–5, which indicates that the technology can be produced in a laboratory environment. According to this maturity, several aspects for serial MM parts need to be developed, but the potential of the technology has been demonstrated. Thus, the next important step is to identify lead applications, which benefit from MM manufacturing and hence foster the industrialization of these processes.

Capability of Multi-Material Laser-Based Powder Bed Fusion—Development and Analysis of a Prototype Large Bore Engine Component

“…Upon visual inspection of the prototype components, all four nozzles were successfully manufactured. It can be concluded that the methods described in previous research for MM part generation utilizing PBF-LB/M can be applied to complex industrial applications [2,4,5,10,39].…”

“…The build job was created from the CAD model. Therefore, separate models were derived for each material [2]. Thus, the steel body volume and the copper inlet volume were exported as STL files.…”

“…The objective of this paper is to demonstrate an advancement in multi-material manufacturing (MM) by laser-based powder bed fusion (PBF-LB/M) technology, as defined in ISO/ASTM 52900 [1]. The current state of three-dimensional, metallic multi-material structures manufactured by PBF-LB/M is believed to be at a manufacturing readiness level (MRL) of 4 to 5 [2]. At this maturity level, a technology is demonstrated in a laboratory environment, including processes sufficient to produce technology demonstrators (compare definition of MRL scale in [3]).…”

“…Based on the PBF-LB/M process characteristics, a three-dimensional MM structure is defined as a structure with "material transition [s] in at least two dimensions" or, equally, as a structure with "material transition [s]) between and within layers" [2,4]. Considering the material combinations that are utilized for MM structures, it is found that • metal-metal combinations are investigated in eleven publications, especially aluminum-copper [4], steel-nickel [5], and steel-copper [4][5][6][7][8][9][10][11][12][13][14]; moreover,…”

“…Future research must be focused on eliminating cross-contamination during the process, since this impedes the generation of reliable results for further process optimization. Advanced, holohedral deposition concepts that are currently in development appear to have the highest potential to solve the issue of cross-contamination [2,[45][46][47]. While MM nozzles and prior research were executed on AM systems in a laboratory environment, professional AM system suppliers have announced their intent to provide multi-material capabilities in their PBF-LB/M systems [48].…”