SUNConferences, COMA '13

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Additive Manufacturing of Gradient and Multimaterial Components
Michael Schmidt, Michael Karg, Tobias Laumer

Last modified: 2013-08-20

Abstract


Selective Laser Melting (SLM) is a manufacturing technique which is nowadays mainly used to build prototypes from a single material. Melting powder layer by layer offers geometrical freedom that cannot be achieved otherwise. This potential for complex-shaped workpieces is rarely exploited so far. The use of multi-material and gradient materials for SLM enables the combination of different materials and the variation of their microstructure in one part. Such composite structures can fulfill different product requirements with a single building process, whereas at the moment such devices are assembled from several independently produced parts. Saving process steps compared to the conventional production thus saves costs.In order to reach this aim research in polymeric and metallic SLM isĀ  necessary. For realizing multi-material-parts from polymers, at first relevant material properties concerning compatibility have to be analysed. These are for example the melting and the solidification behaviour, the compatibility of the melts or the adhesion forces between the particles. Thus, a modification of the powders is done in order to give them tailored properties, e.g. a specific melting or crystallisation temperature. Furthermore an adequate mechanism for the simultaneous deposition of multiple materials and a novel approach for the energy distribution required for the preheating and melting are investigated. The already existing choice to either melt any given volume element or have it remaining as loose metal powder shall be transferred and detailed to the level of microstructure. Powder systems with particles of different sizes and elemental composition are being developed. These allow different properties resulting from metallurgical microstructures realized by locally adjusted process regimes. The research centers around aluminum alloys, which, considering achievable specific strengths, surpass die-cast alloys used so far in laser beam melting roughly by a factor of 2. Taking together all these aspects, new potential for lightweight design is unlocked.


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