Mechanical Reinforcement of Additively Manufactured Ceramics with Boron Nitride Nanotubes

Ceramic materials face significant challenges in industrial applications due to their inherent fragility and limited manufacturability. These limitations can potentially be overcome through the use of reinforcements and additive manufacturing (AM) techniques. Boron nitride nanotubes (BNNTs) possess exceptional structural and physical properties, making them promising candidates for reinforcing ceramics to create lightweight, strong, and durable ceramic materials. These characteristics are attractive to a number of industries, such as aerospace, automotive, and biomedical sectors. The reinforcement potential of BNNTs for ceramic composites is supported by our recent findings of efficient interfacial load transfer in BNNT-ceramic nanocomposites, which is attributed to the partially ionic B-N bonding and the resulting rugged anisotropic energy landscape. Here, we investigate the bulk mechanical properties of AM-produced BNNT-reinforced silica (SiO2) nanocomposites. Our study aims to elucidate how the superior interfacial load transfer characteristics observed at the nanoscale translate into enhancements in the bulk mechanical properties of these nanocomposites. The BNNT-silica nanocomposites employed in our study are additively manufactured using digital light processing (DLP) techniques. Our findings demonstrate that the incorporation of a small quantity of BNNTs can significantly improve the bulk mechanical properties (flexural modulus, strength, and fracture toughness) of AM-produced ceramic nanocomposites. We further analyze the local interfacial load transfer within the AM nanocomposite through in situ Raman micromechanical measurements. The findings provide valuable insights into the role of nanotube-ceramic interfacial strength in enhancing the mechanical properties of the nanocomposite. Our research contributes to a better understanding of the relationship between process, structure, and properties in AM-produced ceramic nanocomposites and the development of durable and reliable ceramics technology.