On the nature of cracks and voids in nuclear graphite
On the nature of cracks and voids in nuclear graphite
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DOI：
10.1016/j.carbon.2016.03.011
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发表时间：
2016-07-01
期刊：
影响因子：
10.9
通讯作者：
Brydson, R. M. D.
中科院分区：
文献类型：
--
作者：
Freeman, H. M.;Jones, A. N.;Brydson, R. M. D.
首次结合使用透射电子显微镜 (TEM)、电子能量损失谱 (EELS)、能量色散 X 射线 (EDX) 和能量过滤 TEM (EFTEM) 对中子辐照核级石墨中的微裂纹进行了详细检查。对来自未辐照 A 级桩 (PGA) 和三个辐照英国实验桩“O”(BEPO) 石墨样本的填料颗粒进行了研究，接收剂量范围为每原子 0.4 至 1.44 位移 (dpa)，辐照温度为 20 至 120 摄氏度。我们认为，微裂纹的浓度和潜在尺寸随着中子辐照的增加而增加，并表明无序碳材料存在于一定范围内。所有样本（包括未辐照材料）中均存在微裂纹（大小和形状各异）。 EFTEM 和 EELS 数据表明，这些裂纹含有比周围块状石墨密度和石墨特性更低的碳材料。部分填充的微裂纹的存在对于开发用于预测核石墨中辐射引起的尺寸和性能变化的微观结构模型具有潜在的重大影响。 (C) 2016 Elsevier Ltd. 保留所有权利。
Microcracks in neutron-irradiated nuclear grade graphite have been examined in detail for the first time using a combination of transmission electron microscopy (TEM), electron energy loss spectroscopy (EELS), energy dispersive X-ray (EDX), and energy filtered TEM (EFTEM). Filler particles from both unirradiated Pile Grade A (PGA) and three irradiated British Experimental Pile 'O' (BEPO) graphite specimens were investigated with received doses ranging from 0.4 to 1.44 displacements per atom (dpa) and an irradiation temperature of between 20 and 120 degrees C. We suggest that the concentration and potentially the size of microcracks increase with increasing neutron irradiation and show that disordered carbon material is present in a range of microcracks (of varying size and shape) in all specimens including unirradiated material. EFTEM and EELS data showed that these cracks contained carbon material of lower density and graphitic character than that of the surrounding bulk graphite. The presence of partially filled microcracks has potentially significant implications for the development of microstructural models for the prediction of radiation-induced dimensional and property changes in nuclear graphite. (C) 2016 Elsevier Ltd. All rights reserved.