Rare earth elements and additive manufacturing: a review

Additive manufacturing (AM) has enabled unprecedented design freedom in the fabrication of complex metallic and ceramic geometries; however, many traditional feedstocks are not well-suited for AM, and the incorporation of rare earth elements (REEs) has become increasingly important in improving printability, controlling solidification, refining microstructures, and enhancing end-use performance. Development of AM-tailored materials is necessary to meet the requirements of industrial applications. High-performance materials containing REEs offer unique properties, such as high corrosion resistance and superior mechanical strength, though these elements pose challenges, including limited availability. This review provides a thorough overview of the current state-of-the-art in AM of high-performance metallic and ceramic feedstocks containing REEs, with an emphasis on the interactions with AM processes and final structure performance. The behaviour of high-performance materials containing REEs under the processing conditions in various AM is explored based on the most recent literature. The benefits, challenges, and opportunities associated with metallic and ceramic AM feedstocks containing REEs are discussed. The mechanics of next-generation materials and microstructural features are reviewed and analysed. A roadmap of research gaps, functional applications, industrial adoption, and societal needs is presented with regard to the integration of REEs to enhance structures fabricated via AM processes.