On the damage and fracture of nuclear graphite at multiple length-scales
On the damage and fracture of nuclear graphite at multiple length-scales
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DOI：
10.1016/j.jnucmat.2017.06.021
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发表时间：
2017-09
影响因子：
3.1
通讯作者：
Dong Liu;K. Mingard;Oliver Thomas Lord;P. Flewitt
中科院分区：
文献类型：
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作者：
Dong Liu;K. Mingard;Oliver Thomas Lord;P. Flewitt
Gilsocarbon石墨作为英国先进气冷堆堆芯的中子减速剂和承载部件，具有复杂的微观结构特征，包括尺寸从纳米到毫米的长度尺度范围内的缺陷/孔隙。因此，当不同长度尺度的试样变形时，这种材料表现出不同的特性。在这项工作中，这种材料的变形和断裂的特点是usingin situmethods的微米尺寸（细观尺度）的试样，然后将结果与那些测量的长度尺度较小，在宏观尺度进行比较。在微观尺度上，对一定体积的材料（2 × 2 × 10 μm）进行取样，排除微观和宏观尺寸的孔隙，测得的强度高达1000 MPa（弹性模量约为67 GPa）。当试样尺寸增加一个数量级到中尺度时，由于包含微米尺寸的孔，强度降低到约100 MPa（约20 GPa的弹性模量）。对于包括毫米级孔隙的较大工程尺寸试样，材料的强度平均约为20 MPa（弹性模量约为11 GPa）。在为相关多尺度建模选择适当数据的背景下，讨论和考虑了数据中的这一趋势。
Gilsocarbon graphite, as a neutron moderator and load-bearing component in the core of the UK fleet of Advanced Gas-Cooled Reactors, possesses complex microstructural features including defects/pores over a range of length-scales from nanometres to millimetres in size. As a consequence, this material exhibits different characteristics when specimens of different length-scale are deformed. In this work, the deformation and fracture of this material have been characterised usingin situmethods for specimens of micrometre size (meso-scale) and the results are then compared with those measured one length-scale smaller, and those at the macro-scale. At the micro-scale, sampling a volume of material (2 × 2 × 10 μm) excludes micro- and macro-size pores, the strength was measured to be as high as 1000 MPa (an elastic modulus of about 67 GPa). When the specimen size is increased by one order of magnitude to the meso-scale, the strength is reduced to about 100 MPa (an elastic modulus of about 20 GPa) due to the inclusion of micro-size pores. For larger engineering-size specimens that include millimetre-size pores, the strength of the material averages about 20 MPa (an elastic modulus of about 11 GPa). This trend in the data is discussed and considered in the context of selecting the appropriate data for relevant multi-scale modelling.