Ternary layered material MAX/MAB phases have become a highly promising candidate for fourth-generation nuclear energy systems, combining the excellent properties of metals and ceramics. This paper reviewed the irradiation response and resistance mechanisms of Ti/Cr/Zr/Nb/V/Ta-based MAX phases, doped/entropy-enhancing MAX phases, and MAB phases. The performance differences between the MAX/MAB phases under irradiation with neutrons, heavy ions, self-ions, He ions, protons, or electrons were investigated. Studies have confirmed that they possess high damage tolerance and resistance to amorphization. This is manifested in the following aspects: accommodating point defects through antisite defects and Frenkel defects; resisting amorphization via atomic rearrangement and crystalline transformation; capturing He atoms by the low-bond-energy A-layer and restricting the growth of He bubbles through M-X layers or B layers; inhibiting further diffusion and penetration of energetic particles; and achieving defect annihilation and damage recovery during high-temperature irradiation and annealing processes. Finally, scientific research strategies are proposed, including regulating MAX/MAB phases to achieve optimal entropy values, designing component structures based on electronegativity and lattice distortion, and investigating the synergistic effects of multiple irradiation particles. Additionally, prospects for the further development of MAX/MAB phases in nuclear energy systems are presented.

This study focuses on the resistance of nanocrystalline SiC coatings in reactors to He ion irradiation damage, revealing the crucial role of grain boundaries. In the nanocrystalline SiC coating, high-density grain boundaries (GBs) and stacking faults (SFs) formed a GB–SF network. This network preferentially captured He atoms and inhibited the nucleation and growth of He bubbles and dislocations within the lattice. Moreover, the decrease in He atoms within the lattice accelerated the recombination of lattice defects. Although the abundant grain boundaries lead to extensive nucleation of dislocations, they restrict the growth of dislocations. Eventually, large He bubbles, continuous gas-filled disc (CGD)-type platelets, and black spots formed at the grain boundaries. Compared with traditional coarse-crystalline chemical vapor deposition (CVD)-SiC, this unique defect structure remarkably reduced the hindrance to dislocation movement and enhanced the resistance of the coating to irradiation hardening. This provides a key reference for the research on optimizing the in-reactor service performance of SiC through grain-boundary regulation strategies.