Bio-inspired structured boron carbide-boron nitride composite by reactive spark plasma sintering
Xie, Sky Shumao
Tok, Alfred Iing Yoong
Date of Issue2013
School of Materials Science and Engineering
Nature creates composite materials with complex hierarchical structure that possesses impressive mechanical properties enhancement capabilities. An approach to improve mechanical properties of conventional composites is to mimic biological material structured ‘hard’ core and ‘soft’ matrix system. This would allow the efficient transfer of load stress, dissipate energy and resist cracking in the composite. In the current study, reactive spark plasma sintering (SPS) of boron carbide B4C was carried out in a nitrogen N2 gas environment. The process created a unique core-shell structured material with the potential to form a high impact-resistant composite. Transmission electron microscopy observation of nitrided-B4C revealed the encapsulation of B4C grains by nano-layers of hexagonal-boron nitride (h-BN). Effect of the h-BN contents on hardness were measured using micro- and nano-indentation. Commercially available h-BN was also mechanically mixed and sintered with B4C to compare the effectiveness of nitrided B4C. Results have shown that nitrided B4C have higher hardness value and the optimum content of h-BN from nitridation was 0.4%wt with the highest nano-indentation hardness of 56.7GPa. The high hardness was attributed to the h-BN matrix situated between the B4C grain boundaries which provided a transitional region for effective redistribution of the stress in the material.
Virtual and physical prototyping
© 2013 Taylor & Francis. This is the author created version of a work that has been peer reviewed and accepted for publication by Virtual and Physical Prototyping, Taylor & Francis. It incorporates referee’s comments but changes resulting from the publishing process, such as copyediting, structural formatting, may not be reflected in this document. The published version is available at: [doi:http://dx.doi.org/10.1080/17452759.2013.862959].