An overview of additively manufactured metal matrix composites: preparation, performance, and challenge

Metal matrix composites (MMCs) are frequently employed in various advanced industries due to their high modulus and strength, favorable wear and corrosion resistance, and other good properties at elevated temperatures. In recent decades, additive manufacturing (AM) technology has garnered attention as a potential way for fabricating MMCs. This article provides a comprehensive review of recent endeavors and progress in additive manufacturing of MMCs, encompassing available AM technologies, types of reinforcements, feedstock preparation, synthesis principles during the AM process, typical AM-produced MMCs, strengthening mechanisms, challenges and future interests. Compared to conventionally manufactured MMCs, AM-produced MMCs exhibit more uniformly distributed reinforcements and refined microstructure, resulting in comparable or even better mechanical properties. In addition, AM technology can produce bulk MMCs with significantly low porosity and fabricate geometrically complex MMC components and MMC lattice structures. As reviewed, many AM-produced MMCs, such as Al matrix composites, Ti matrix composites, Nickel matrix composites, Fe matrix composites, etc., have been successfully produced. The types and contents of reinforcements strongly influence the properties of AM-produced MMCs, the choice of AM technology, and the applied processing parameters. In these MMCs, four primary strengthening mechanisms have been identified: Hall-Petch strengthening, dislocation strengthening, load transfer strengthening, and Orowan strengthening. AM technologies offer advantages that enhance the properties of MMCs when compared with traditional fabrication methods. Despite the advantages above, further challenges of AM-produced MMCs are still faced, such as new methods and new technologies for investigating AM-produced MMCs, the intrinsic nature of MMCs coupled with AM technologies, and challenges in the AM processes. Therefore, the article concludes by discussing the challenges and future interests of additive manufacturing of MMCs.