Engineered microcracking in alumina/aluminum titanate composites: A pathway to enhance nonlinear mechanical behavior and fracture energy

Refractory materials for high-temperature applications often face thermal shock challenges. Incorporating aluminum titanate (Al₂TiO₅, AT) into an alumina matrix allows to tailor a relevant microcracked network via thermal expansion mismatch, enhancing thermal shock resistance. This study examines thermomechanical behavior of Al₂O₃/AT composites (0–10 wt% AT) using various specific experimental high-temperature techniques. Increasing AT content amplifies microcrack density, reducing Young’s modulus from 360 GPa (pure alumina) to 40 GPa (10 wt% AT). Comparison of experimental results of Young’s modulus variation versus temperature with Hashin-Shtrikman model allow to well quantify damage evolution. Composites with 10 wt% AT exhibit a strong nonlinear stress-strain behavior in tension and an exceptional strain to rupture (1.6 %), while miniaturized wedge splitting test confirms reduced brittleness and elevated fracture energy. These findings underline the role of tailored microcracking in optimizing thermomechanical performance, offering insights for designing refractory materials with improved durability under extreme thermal cycling.