Investigation of inducing rising R-curves in all-brittle systems with stiff network structure

Abstract

In all-brittle systems, inducing rising crack-resistance curves (R-curve) remains challenging due to high interface strength, especially introducing a stiffer additive phase. Nevertheless, we connected stiff phase TiC as network structure in Si₃N₄ matrix and facilitated their in-situ reaction. Morphological characterisation indicates that a submicron SiC network with micro/nano-pores was formed in the TiC network, which provides a continuous “channel” to induce the deflection of cracks within stiff network and results in rising R-curves. In samples with direct TiN introduction, cracks are likely to be blocked by the TiN network rather than propagating along the network. Finally, we deduced the formation process of SiC network with micro/nano pores based on the morphological characterisation and the reaction mechanism between Si₃N₄ and TiC. These findings provide valuable insights into the structural and component design associated with toughening efforts for ceramic composites.