Abstract:Due to their high melting points, excellent high-temperature mechanical properties, and radiation resistance, molybdenum-rhenium (Mo-Re) alloys have been considered as primary candidates for fuel cladding and core structural materials used in advanced nuclear reactors. In this study, molecular dynamics simulations were employed to systematically investigate the effects of displacement cascades on the mechanical properties of Mo-Re single-crystal solid-solution alloys with different Re contents (5% and 14%), using pure Mo single crystals as a benchmark. The results indicate that increasing the Re content could activate more slip systems within the Mo-Re single-crystal solid-solution alloys under tensile stress, thereby effectively enhancing their plasticity. Results further indicated that displacement cascades could significantly degrade both the tensile strength and plasticity of the Mo-Re alloys. The underlying physical mechanism may be from the defects introduced by the cascades, which can induce localized stress concentrations and energy perturbations, resulting in a reduction in the critical stress required to activate slip systems, thereby accelerating material yielding and decreasing the uniform elongation of the single-crystal solid-solution alloys. Therefore, the results of this study elucidate the influence of displacement cascades on the tensile mechanical properties of Mo-Re single-crystal solid-solution alloys, as well as the underlying atomic-scale mechanisms, providing valuable scientific insights for the design and selection of materials for advanced nuclear reactors.