In situ TEM observation of the evolution of helium bubbles in Hastelloy N alloy during annealing
In situ TEM observation of the evolution of helium bubbles in Hastelloy N alloy during annealing
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DOI：
10.1016/j.jnucmat.2020.152184
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发表时间：
2020-08
影响因子：
3.1
通讯作者：
Jizhao Liu;Hefei Huang;Renduo Liu;Zhenbo Zhu;Qiantao Lei;Awen Liu;Yan Li
中科院分区：
文献类型：
--
作者：
Jizhao Liu;Hefei Huang;Renduo Liu;Zhenbo Zhu;Qiantao Lei;Awen Liu;Yan Li
利用透射电子显微镜对Hastelloy N合金在400℃、500℃和600℃三种温度下热处理过程中氦气泡的动态演化过程进行了观察。结果表明，在400℃和500℃保温60min后，晶内氦气泡几乎不粗化。虽然在500℃下退火的样品在晶界形成了新的氦气泡，但由于表面扩散较小、氦气泡之间的距离以及两个颗粒的取向不同，这些晶间氦气泡并没有聚集在一起。用Carnhan-Starling硬球模型计算的氦气泡的高内压表明，600℃热处理的样品在氦气泡粗化过程中迁移和合并(MC)机制更为明显，但MC机制受到铬原子和位错线的限制，从而导致了被抑制的MC机制的出现。
In situtransmission electron microscopy (TEM) was used to capture the dynamic evolution of helium bubbles in Hastelloy N alloy during annealing at 400 °C, 500 °C and 600 °C. The TEM results showed that intragranular helium bubbles hardly coarsened after annealing at 400 °C and 500 °C for 60 min. Although the formation of a new helium bubble was observed at the grain boundary for the sample annealed at 500 °C, these intergranular helium bubbles did not coalesce due to the low surface diffusion, the distance between helium bubbles and the misorientation of two grains. The high internal pressure of the helium bubbles calculated using the Carnahan–Starling hard sphere model illustrated that the migration and coalescence (MC) mechanism was more apparent in helium bubbles coarsening for the sample annealed at 600 °C. However, the MC mechanism was restricted by chromium atoms and dislocation lines, which caused the emergence of the suppressed MC mechanism.