Morphology of ceramic regulates the deposition behavior and mechanical properties of cold spray additive manufactured Al₂O₃/2024 aluminum matrix composites

The morphology and size of ceramic particles in cold spray additive manufacturing (CSAM) of metal matrix composites affects strongly particle acceleration behavior and deposition mechanisms. This study focuses Al₂O₃/2024 aluminum matrix composites and investigates the effect of the morphology of ceramic morphology and content in powder on the microstructure and mechanical properties with numerical simulation and experiments. The deposition mechanism of ceramic particles has been identified, as well as and the optimal properties of powder composition. It was shown that increasing ceramic content in the powder results in a significant deviation of ceramic content in the deposit from the design. At lower ceramic powder content (10 vol% and 20 vol%), the fracture surface of irregular ceramic deposits shows dimples, indicating an increased metallurgical bonding ratio compared to deposits produced with spherical ceramic powder. The tensile strength of deposits produced with spherical ceramic powders surpasses those of those produced with irregular ceramic powders. The study identified the optimal powder composition with particles size of 20 μm and spherical ceramic powder content of 30 vol%. There are performance differences between irregular and spherical ceramic powder deposits because the antagonism between positive tamping effect and the negative effect of the weak metal/ceramic powder interface. The deposit hardness and wear resistance are strongly affected by ceramic content, where larger ceramic powder content is associated with increased hardness and improved wear resistance. The latter improves significantly when it exceeds 7.4 vol%.