Ultrafine-bubble-water-promoted nanoceramic decoration of metal powders for additive manufacturing

Abstract Design of composite powders for exploiting the multifunctionality of metallic nanocomposites via laser additive manufacturing (AM) is challenging. Conventional ball-milling processes are prone to cause uncontrollable powder morphology and reduced flowability, while recently-developed nano-decoration technologies are limited by complicated processing and impurity inclusion. Herein, a facile and scalable approach was developed using ultrafine bubble (UFB)-assisted heteroagglomeration to fabricate high-concentration, impurity-free nanoceramic/metal composite powders. Individual ZrO2 or Al2O3 nanoparticles up to ~ 10 wt% were homogeneously decorated on the surface of Ti-6Al-4V powders through the bridging effect of negatively charged UFBs, leading to enhanced flowability and laser absorptivity. The nanoceramics were completely decomposed and dissolved into the matrix upon laser irradiation; consequently, a unique Ti nanocomposite exhibiting both high strength and ductility was obtained. Our work provides new insights into the application of UFBs and the fabrication of multifunctional AM components.