Process Development for Additive Manufacturing of Multi-Material Particle Dampers

The additive manufacturing process of powder bed fusion using a laser beam for metals (PBF-LB/M) is characterized by many degrees of freedom, a high resolution and the availability different metallic materials. In order to fully exploit the potential of the manufacturing process, functions and effects that increase the efficiency of components can be integrated directly during additive manufacturing. This paper focuses on the integration of damping effects by means of particle damping. Particle dampers can reduce vibrations due to energy dissipation as a result of impact and friction movements. The necessary particles are left in the form of unmelted powder in closed cavities within the manufactured component. The damping behavior is also largely dependent on the particle material used. Based on the literature, a higher damping performance is expected when a particle material with higher density is used. Due to the PBF-LB/M process, fused structural material and unfused powder material were up to now identical. This paper examines how particle dampers can be manufactured in which the fully fused structural material differs from the unfused powder. It is investigated whether multi-material PBF-LB/M can be used to manufacture components from the high-strength aluminum alloy Scalmalloy® in combination with unmolten tungsten powder as the particle material. Parameters for the multi-material deposition as well as for the fusion of the aluminum alloy are identified. A volume energy density of 56 J/mm³ in combination with heat treatment at 325° C is identified as optimal, whereby a material density of >99.8% and a tensile strength of 522 MPa are achieved for Scalmalloy®. These parameters are then used to produce test specimen particle dampers. An X-ray examination of these test specimens shows the successful multi-material manufacturing with a powder filling ratio of 89% inside the particle dampers.