摘要
Extreme inert-matrix materials, represented by SiC, due to their poor sinterability, necessitate additives for densification, but yet compromise purity and reliability. This study reports an additive-free strategy to achieve a damage-tolerant in-situ TiCx/SiC composites by hot-pressing at 1850 degrees C with 30 MPa for 1 h, where the intact MXene-topology layered TiCx architecture is successfully introduced into inert-SiC-matrix by leveraging MAXphase Ti3AlC2 as a dual precursor for reinforcer and densification. The obtained composite with 40 wt% Ti3AlC2 usage achieves optimum synergy of density and mechanics, especially the superb toughness over 10 MPa & sdot;m1/2. Micrography reveals an unreported in-situ MXene-like layered TiCx reinforcement performing multilevel energy-dissipation pathways for damage tolerance. DFT investigation atomically elucidates an underlying thermodynamically-induced TiCx/SiC interface reconstruction behavior triggering a simultaneous improvement on interfacial wettability, adhesion and ductility. Eventually, we proposed a solid-vapor mechanism window of synergistic anti-Ostwald ripening and self-vaporization under vacuum hot-pressing, which enables the MXenesubstructure preserving, self-purification and high-densification for such inert-matrix composites. This study offers a spanking-new perspective on the roles of the MAX-phases/MXenes in the synthesis and interface engineering of advanced structural materials beyond traditional understanding, and inspires an avenue of simple and low-energy and large-scale preparation of high-performance but difficult-to-sinter bulks for harsh environments.