发表机构
Indian Institute of Science（印度科学研究所）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文通过分子动力学模拟研究钨中位错与空位环的相互作用，明确其演化机制，建立原子级障碍强度向介观本构参数的转化框架，为提升聚变堆材料辐照硬化预测能力提供物理基础。
AI 中文摘要
聚变反应堆用结构材料经受中子辐照，产生的缺陷群通过辐照硬化决定材料的力学响应。基于物理的介观本构模型需要准确描述位错与缺陷的相互作用，以及关键的：随着辐照诱导缺陷组态变化，塑性变形过程中缺陷形貌和障碍强度如何演化。空位环是解决该问题的理想原型，因为它们是钨中最普遍的辐照诱导缺陷之一，但其与位错的相互作用机制及后续演化仍知之甚少。本文采用分子动力学模拟，通过改变环尺寸、晶体学取向和位错环相交几何，系统研究钨中刃型位错与空位环的相互作用。平行环表现出强烈的几何依赖行为，根据相互作用几何，会发生完全湮灭、转变为较弱的残余缺陷或缺陷输运。相比之下，倾斜环通过柏氏矢量反应相互作用，形成不可动的<100>位错段，产生显著更高的钉扎强度，且对相交位置几乎不敏感。最后，本文展示了将原子级确定的障碍强度转化为介观模型本构参数（如辐照硬化）的框架。本文建立的机制理解为未来介观本构律提供了物理基础，该本构律明确考虑辐照诱导缺陷群的演化，以及由此产生的位错-缺陷相互作用机制和障碍强度的变化，从而提高超出校准条件的预测能力。
英文摘要
Structural materials in fusion reactors develop irradiation-induced defect populations that govern their mechanical behaviour. While advanced microscopy provides detailed characterisation of such defects, their dynamic evolution through dislocation-defect interactions during plastic deformation remains unresolved. Here, we address this gap using molecular dynamics simulations to resolve dislocation-defect interaction mechanisms and the resulting evolution of defect morphology and obstacle strength. Tungsten is the leading candidate plasma-facing material for fusion reactors, where vacancy loops are common irradiation defects. Using vacancy loops as a prototype defect, we systematically investigate their interactions with edge dislocations by varying loop size, orientation, and dislocation-loop intersection position. Parallel loops exhibit three distinct evolution pathways: complete annihilation, transformation into weaker remnant defects, or defect transport, depending on the intersection position and loop size. In contrast, inclined closed loops undergo dislocation reactions that produce sessile $\langle010\rangle$ dislocation segments, leading to substantially higher obstacle strengths with little sensitivity to the intersection position. Repeated dislocation interactions further demonstrate that the defect landscape is not static: remnant defects can persist, transform, or lose their ability to impede subsequent dislocations, depending on the preceding interaction mechanism. These results show that the obstacle strength of a vacancy loop is governed not only by its initial size and orientation, but also by its interaction history and the resulting defect structure.
