A study into the effects of irradiation temperature on the damage structures that form during proton-irradiation has been carried out on two commercial Zr alloys in order to develop a more mechanistic understanding of the effect of niobium on dislocation loop evolution. The two Zr alloys (Zircaloy-2 and Low-Sn ZIRLO™) were proton irradiated to a damage level of ∼2 dpa at 280 °C, 350 °C and 450 °C. Detailed dislocation analysis was carried out using on-axis bright-field scanning transmission electron microscopy combined with spectral imaging and synchrotron x-ray line profile analysis. The analysis revealed a significant difference in the effect of irradiation temperature on loop size between the two alloys. In the case of the Nb-free Zr-alloy (Zircaloy-2), an increase in irradiation temperature results in a marked increase in a-loop diameter, by a factor of ∼7.5 from 280 to 450 °C, and a stark decrease in the dislocation line density. In contrast, the Nb-containing Zr-alloy (Low-Sn ZIRLO™) showed very little variation of loop size and line density over the same radiation temperature range. The STEM-based spectral imaging revealed irradiation-induced nano-clustering found throughout the matrix in Low-Sn ZIRLO™, which is not present in the case of Zircaloy-2. Therefore, it is proposed that Nb plays a crucial role in the evolution of dislocation loops in Zr through the formation of irradiation precipitation throughout the matrix.

为了对铌对位错环演化的影响有更深入的机械理解，已经对两种市售Zr合金进行了辐照温度对质子辐照过程中形成的损伤结构的影响的研究。在280°C，350°C和450°C的温度下，对两种Zr合金（Zircaloy-2和Low-Sn ZIRLO™）进行了质子辐照，其损伤水平约为2 dpa。使用轴上明场扫描透射电子显微镜结合光谱成像和同步加速器X射线线轮廓分析进行了详细的位错分析。分析显示两种合金之间的辐照温度对环尺寸的影响存在显着差异。对于无Nb的Zr合金（Zircaloy-2），辐照温度的升高会导致a环直径的显着增加，从280到450°C约降低7.5倍，位错线密度急剧下降。相反，在相同辐射温度范围内，含Nb的Zr合金（Low-Sn ZIRLO™）的回路尺寸和线密度变化很小。基于STEM的光谱成像显示在Low-Sn ZIRLO™的整个基质中都发现了辐射诱导的纳米簇，这在Zircaloy-2中不存在。因此，提出通过在整个基质中形成辐射沉淀，Nb在Zr的位错环的演变中起着至关重要的作用。基于STEM的光谱成像显示在Low-Sn ZIRLO™的整个基质中都发现了辐射诱导的纳米簇，这在Zircaloy-2中不存在。因此，提出通过在整个基质中形成辐射沉淀，Nb在Zr的位错环的演变中起着至关重要的作用。基于STEM的光谱成像显示在Low-Sn ZIRLO™的整个基质中都发现了辐射诱导的纳米簇，这在Zircaloy-2中不存在。因此，提出通过在整个基质中形成辐射沉淀，Nb在Zr的位错环的演变中起着至关重要的作用。