Self-healing materials are highly desirable in the nuclear industry to ensure nuclear security. Although extensive efforts have been devoted to developing self-healing materials in the past half century, very limited successes have been reported for ceramics or metals. Here, we report an intrinsic self-healing material of Ti3AlC2 MAX phase, which exhibits both ceramic and metallic properties, and a strategy for further enhancing the self-healing via irradiation is proposed. Quantitative in situ transmission electron microscopy tensile testing reveals that the fracture strength of 1.58 GPa is achieved on thoroughly fractured Ti3AlC2, corresponding to the self-healing efficiency of 19.8%, which is increased to 28.1% after irradiation. In situ irradiation experiments, atomic-resolution characterizations, and molecular dynamics simulations reveal that spontaneous rebonding of partial atoms on fracture surfaces is responsible for the self-healing, and irradiation-enhanced atomic migration, interplanar spacing increment, and gap-filling contribute to the self-healing enhancement.
Keywords: MAX phase; in situ; irradiation; self-healing efficiency; spontaneous rebonding.