Molecular dynamics simulation of tensile deformation behavior of single-crystal Fe–Cr–Al before and after irradiation

Fe–Cr–Al alloy is one of the candidate materials for reactor fuel cladding due to excellent high-temperature oxidation resistance; however, it has significant irradiation embrittlement and hardening. To understand the effect of Cr and Al and the defects (point defects, clusters, and nanocracks) produced from radiation damage on the mechanical properties, the uniaxial tensile property of single-crystal Fe–Cr–Al is investigated. The results show that, due to the presence of Cr and Al, the phase transformation from body-centered-cubic to face-centered-cubic is impeded and the formation of defects and amorphous structures is promoted, leading to the reduction of Young’s modulus and the ultimate tensile stress. Interstitials are the main factor in Frenkel pairs contributing to the reduction of mechanical properties due to the high shear stress and lattice distortion. The collapse of the nanocrack causes the increase of Young’s modulus and the decrease of the ultimate tensile strength. Graphical abstract: [Figure not available: see fulltext.].