EUROPEAN CONGRESS AND EXHIBITION ON ADVANCED MATERIALS AND PROCESSES - EUROMAT 2021

Space applications require reliable components that fulfill their goal while being as light as possible. In the last years, the use of additive manufacturing in the space industry has grown drastically as it allows to produce more complex parts with minimum machining. It led to a reduction of the number of components and allowed the use of tools such as topology optimization to reduce the weight of the parts. However, even by combining Additive Manufacturing and Topology Optimization, lightweigthing is still limited by the ratio of mechanical properties to the density of the selected material. One way to change this ratio is to produce Metal Matrix Composites (MMCs). MMCs are composed of a continuous metallic matrix reinforcement by a second phase, generally ceramics. The reinforcement typically takes most of the load leading to increased mechanical properties.

In the present work, we focus on a Laser Powder Bed Fusion process, also known as Selective Laser Melting (SLM), as a way to produce MMCs. A thorough analysis of the literature was conducted to define MMC candidates with the most potential of high specific stiffness. Most of the SLM made MMCs are produced from a mix of two or more powder stocks. However, having a multiple constituents powder mix can creates issues such inhomogeneity, reduced flowability and processability as well as increased potential of unwanted phases. In order to address those challenges, several size of reinforcement particles and mixing procedure were used. In addition, a commercially available composite powder was utilized to reduce the absorption inhomogeneity. Several MMCs were produced over a wide range of processing parameter and their microstructure and mechanical properties were characterized. Particular attention was drawn on the composition and homogeneity of the resulting parts.