Abstract This paper presents historical results of graphite irradiation-induced creep experiments that were performed at Oak Ridge National Laboratory from the 1950's to the 1970's. These experiments were performed at temperatures from 150°C to 1000 °C, and bend stresses ranging from 500 to 5000 psi (∼3.3–34.5 MPa). The experimental setup utilized in-situ measurement of specimen displacement, on-line applied stress control, and the ability to change stress during the experiment. The different stress conditions showed that the primary creep strain and the steady-state creep rates both have a linear stress dependence. The temperature range used in this work resulted in trends that have not be previously presented in the literature: 1) a linear dependence of primary creep strain on temperature, and 2) the shape of steady state creep rate versus temperature (see graphical abstract). The maximum dose in the specimens was 0.9 dpa, which is sufficient to achieve steady-state creep without the structural changes that alter the observed creep behavior. The results from this experiment provide evidence that dispels that the pinning-unpinning model describes the mechanism of irradiation creep in graphite. Instead these results suggest a dislocation climb mechanism is the probable mechanism for creep within the crystalline regions.

中文翻译：

---

测量辐照诱导石墨蠕变的历史实验

摘要 本文介绍了 1950 年代至 1970 年代在橡树岭国家实验室进行的石墨辐照诱导蠕变实验的历史结果。这些实验在 150°C 至 1000°C 的温度下进行，弯曲应力范围为 500 至 5000 psi（~3.3-34.5 MPa）。实验装置利用试样位移的原位测量、在线应用应力控制以及在实验过程中改变应力的能力。不同的应力条件表明初级蠕变应变和稳态蠕变速率都具有线性应力依赖性。这项工作中使用的温度范围导致了之前文献中没有出现过的趋势：1）初级蠕变应变对温度的线性依赖性，和 2) 稳态蠕变速率与温度的关系（参见图形摘要）。样品中的最大剂量为 0.9 dpa，足以实现稳态蠕变，而不会改变观察到的蠕变行为的结构变化。该实验的结果提供了证据，证明钉扎-脱钉模型描述了石墨中辐照蠕变的机制。相反，这些结果表明位错爬升机制是晶体区域内蠕变的可能机制。该实验的结果提供了证据，证明钉扎-脱钉模型描述了石墨中辐照蠕变的机制。相反，这些结果表明位错爬升机制是晶体区域内蠕变的可能机制。该实验的结果提供了证据，证明钉扎-脱钉模型描述了石墨中辐照蠕变的机制。相反，这些结果表明位错爬升机制是晶体区域内蠕变的可能机制。