中文摘要：

因为照耀变硬和韧性的损失，在在原子环境的严重照耀下面的结构材料被知道降级，源于象空缺， interstitials 和脱臼环那样的导致照耀的缺点，等等。在这份报纸，我们为单个谷物和多晶的总数的机械行为两个都在被探索的照耀的多相的多晶的电子消息传输方式材料开发一个 elasticviscoplastic 模型。在显微镜的谷物规模，我们使用内部可变模型并且建议一个新 tensorial 损坏描述符代表缺点循环的几何学字符，它便于缺点循环进化和脱臼缺点相互作用的分析。在宏观的多晶体规模，前後一致的计划被扩大考虑多相的问题并且过去常衔接单个谷物行为到多晶体性质。基于建议模型，我们发现有导致照耀的缺点环的增加的变硬工作的系数减少，和机械性质的取向 / 负担依赖主要被归因于不同 Schmid 因素。在多晶的规模，纯 Fe 的数字结果与照耀实验数据匹配很好。模型进一步被扩大由考虑在分散氧化物的加强的钢预言 dispersoids 的变硬的效果鞠躬的 Orowan。谷物尺寸和照耀的影响被发现竞争统治材料的加强的行为。

英文摘要：

Structure materials under severe irradiations in nuclear environments are known to degrade because of irradiation hardening and loss of ductility,resulting from irradiation-induced defects such as vacancies,interstitials and dislocation loops,etc.In this paper,we develop an elastic-viscoplastic model for irradiated multi-phase polycrystalline BCC materials in which the mechanical behaviors of individual grains and polycrystalline aggregates are both explored.At the microscopic grain scale,we use the internal variable model and propose a new tensorial damage descriptor to represent the geometry character of the defect loop,which facilitates the analysis of the defect loop evolutions and dislocation-defect interactions.At the macroscopic polycrystal scale,the self-consistent scheme is extended to consider the multiphase problem and used to bridge the individual grain behavior to polycrystal properties.Based on the proposed model,we found that the work-hardening coefficient decreases with the increase of irradiation-induced defect loops,and the orientation/loading dependence of mechanical properties is mainly attributed to the different Schmid factors.At the polycrystalline scale,numerical results for pure Fe match well with the irradiation experiment data.The model is further extended to predict the hardening effect of dispersoids in oxide-dispersed strengthened steels by the considering the Orowan bowing.The influences of grain size and irradiation are found to compete to dominate the strengthening behaviors of materials.