Mechanical property evaluation of SiO₂/Al₂O₃ hybrid fiber porous materials: Sintering-Informed microstructural modeling and experimental validation

The macroscopic properties of ceramic fiber porous materials sintered from random fibers are influenced by complex couplings of microscopic factors. For hybrid ceramic fiber porous materials, the lack of effective simulations accounting for fiber interactions makes performance prediction a challenge. In this study, a finite element micro-model with stochastically distributed fibers was established to simulate the compressive behavior of SiO₂/Al₂O₃ hybrid ceramic fiber porous materials. In addition to conventional approaches, a novel inter-fiber bonding model accounting for sintering degree was developed based on fiber surface diffusion simulation. Verified against experimental data, the developed model demonstrates predictive fidelity in simulating compressive behavior, reducing the average strength deviation to −2.29%. Simulation results demonstrate that the macroscopic strength can be enhanced by 14.4% through fully sintering and elevating the sintering degree effectively suppresses fiber buckling. Parameter coupling analysis indicates that porosity and fiber ratio both negatively correlate with compressive strength but exert opposing influences on density. This divergence creates a design trade-off. Ultimately, a comprehensive evaluation framework for the mechanical performance of composite ceramic fiber porous materials was proposed, which can be extended to support the on-demand design and fabrication of hybrid ceramic fiber materials.