Abstract Refining grain size and adding alloying elements are two complementary approaches for enhancing the radiation tolerance of existing nuclear materials. Here, we present detailed in-situ irradiation research on defect evolution behavior and irradiation tolerance of ultrafine W-TiC alloys (thin foils) irradiated with 1 MeV Kr+2 at RT and 1073 K, and compare their overall performance to pure coarse grained tungsten. Loop Burgers vector was studied confirming the presence of loops whose population increased at high temperature. Loop density, average loop area, and overall damage are reported as a function of irradiation dose revealing distinct defect evolution behavior from pure materials. The overall damage generally followed the average loop size trend, which decreased with time for both temperatures, but was higher at 1073 K and attributed to biased vacancy sink behavior of the TiC dispersoids evidenced by large vacancy clusters on their interfaces. By comparison, the overall loop and void damage in pure tungsten was larger by a factor of six and two, respectively. The improved irradiation damage resistance in the alloys is thus attributed to the effect of dispersoids in 1) the enhancement in annihilating defects and mutual defect recombination due to both dispersoids and a higher grain boundary density; 2) decreasing the loop mobility, causing shrinkage and annihilation of loop density, which was confirmed via in-situ video. Several mechanisms are illustrated to describe the performance of the complex alloy system. The results motivate further experimental and modeling research that aims to understand the many different phenomena occurring at different time scales.

中文翻译：

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高强度超细碳化钨钛合金的原位辐照耐受性研究

摘要 细化晶粒尺寸和添加合金元素是提高现有核材料抗辐射能力的两种互补途径。在这里，我们介绍了在室温和 1073 K 条件下用 1 MeV Kr+2 辐照的超细 W-TiC 合金（薄箔）的缺陷演化行为和辐照耐受性的详细原位辐照研究，并将它们的整体性能与纯粗晶粒钨进行了比较. 对 Loop Burgers 向量进行了研究，确认存在在高温下数量增加的循环。环密度、平均环面积和整体损伤被报告为辐照剂量的函数，揭示了与纯材料不同的缺陷演化行为。总体损坏通常遵循平均环路尺寸趋势，随着时间的推移，两种温度均会下降，但在 1073 K 时更高，这归因于 TiC 弥散体的偏置空位汇行为，其界面上的大空位簇证明了这一点。相比之下，纯钨中的整体环路和空隙损坏分别大了六倍和二倍。因此，合金中改进的抗辐照损伤归因于弥散体的作用：1) 由于弥散体和更高的晶界密度，增强了消除缺陷和相互缺陷复合；2) 降低环路迁移率，导致环路密度收缩和湮灭，这通过原位视频得到证实。说明了几种机制来描述复杂合金系统的性能。