Three-dimensional graphene-carbon fiber network and dual-phase high-entropy alloy for boosting mechanical responses of alumina ceramics

The inherent brittleness significantly limits the structural applications of ceramics. Herein, three-dimensional graphene-carbon fiber (3D G/Cf) network and dual-phase AlCoCrFeNi high-entropy alloy (DHEA) were developed to enhance the mechanical performances of alumina ceramics. Initially, multiscale modeling approach integrating molecular dynamics simulations and 3D finite element simulation was developed to predict the effective interface bonding and mechanical behaviors of Al2O3-DHEA-G/Cf composites. Furthermore, 3D G/Cf network was constructed through covalently bonding via amide linkages (-CO-NH-). Finally, the high-hard and high-tough Al2O3-DHEA-G/Cf composites were fabricated employing spark plasm sintering. The toughening mechanism originates from three synergistic effects: chemical grafting at the graphene-carbon fiber interface forms a three-dimensional reinforcement network ensuring efficient stress transfer, the introduced DHEA provides additional energy dissipation, and the multi-scale architecture spanning from nano-sized graphene to micro-scale carbon fibers enables coordinated toughening.