高损伤辐照下铝微观结构演化与降解机制
Mechanisms of Microstructural Evolution and Degradation in Aluminum under High-Damage Irradiation
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中文总结 AI 辅助
研究铝合金在高损伤辐照下微观结构演化与降解机制，结合传统模拟与IKA方法，确定三个阶段，揭示缺陷转变及协同效应增加辐照硬化，为铝反应堆材料辐照降解提供见解。
中文摘要 AI 辅助
铝合金广泛应用于研究反应堆系统，但辐照引起降解的机制仍了解不足。本文将传统级联重叠分子动力学模拟与加速迭代动力学方法（IKA）相结合，研究50 keV氦辐照下单晶铝中的缺陷演化。基准测试表明IKA再现了级联模拟的基本缺陷动力学，同时能达到更高累积损伤。通过将IKA扩展到更高损伤水平，确定了铝中辐射诱导降解的三个不同阶段：复合驱动湮灭、缺陷积累和汇控吸收。在更高损伤时，弗兰克环解离成肖克利偏位错和阶梯杆位错环，最终驱动层错四面体（SFTs）的形核和生长。这些转变逐渐将可移动缺陷转化为SFTs。最终，间隙和空位环与SFTs的协同效应增加了300 K时铝的辐照硬化。这项工作为铝反应堆材料的辐照诱导降解提供了见解。
英文摘要
Aluminum alloys are widely used in research reactor systems, yet the mechanisms governing irradiation-induced degradation remain poorly understood. Here we combine conventional cascade-overlap molecular dynamics simulations with an accelerated Iterative Kinetic Approach (IKA) to investigate defect evolution in single-crystal Al subjected to 50 keV He irradiation. Benchmarking shows that IKA reproduces the essential defect kinetics of cascade simulations while enabling access to substantially higher accumulated damage. By extending the IKA to higher damage levels, we identified three distinct regimes governing radiation-induced degradation in Al: recombination-driven annihilation, defect accumulation, and sink-controlled absorption. At higher damage, Frank loops dissociate into Shockley partials and stair-rod loops, ultimately driving the nucleation and growth of stacking-fault tetrahedra (SFTs). These transformations progressively convert mobile defects into SFTs. Ultimately, the synergistic effect of interstitial and vacancy loops and SFTs increases irradiation hardening in Al at 300 K. This work provides insight into irradiation-induced degradation in aluminum reactor materials.
