C离子辐照对核级石墨硬度和杨氏模量影响研究

为了探明离子辐照剂量和辐照温度对核级石墨硬度、杨氏模量及微观组织的影响，采用0.02 dpa、0.2 dpa和2 dpa剂量的C4+分别在室温和180℃下辐照核级石墨，利用纳米压痕仪和透射电镜对不同离子辐照条件下核级石墨的性能和微观组织进行研究。结果表明：室温辐照时，硬度和杨氏模量均随着辐照剂量的增加而增加，辐照剂量为2 dpa时，硬度与杨氏模量的峰值分别由未辐照时的0.51 GPa与15.52 GPa急剧增加到2.51 GPa与37.73 GPa。180℃辐照剂量为0、0.02、0.2 dpa时，硬度和杨氏模量也随着辐照剂量的增加而增加，均高于室温辐照相同辐照剂量下硬度和杨氏模量的峰值。当辐照剂量达到2 dpa时，硬度与杨氏模量的峰值从0.2 dpa的1.72 GPa和31.53 GPa迅速降为1.32 GPa和25.91 GPa。石墨硬度和杨氏模量的增加是由于辐照导致石墨内部的微裂纹闭合和基体缺陷增加造成的，180℃辐照2 dpa后硬度和杨氏模量的急剧降低是由于辐照导致石墨发生了非晶化导致的。

Study on the Effect of C-ion Irradiation on Hardness and Young's Modulus of Nuclear-grade Graphite

In order to ascertain the effect of ion irradiation dose and temperature on the hardness, Young's modulus and microstructure of nuclear-grade graphite, 0.02 dpa, 0.2 dpa and 2 dpa C4+ are used in this paper to irradiate nuclear-grade graphite at room temperature and 180℃, respectively. The properties and microstructure of nuclear-grade graphite under different ion irradiation conditions are studied by using nano indentor and transmission electron microscopy. The results show that the hardness and Young's modulus increase with the increase of irradiation dose at room temperature, when the irradiation dose is 2 dpa, the peak values of hardness and Young's modulus increas sharply from 0.51 GPa and 15.52 GPa without irradiation to 2.51 GPa and 37.73 GPa respectively. When the irradiation dose is 0~0.2 dpa at 180℃, the hardness and Young's modulus increase with the increase of irradiation dose, and they are higher than those at room temperature with the same irradiation dose, when the irradiation dose reaches 2 dpa, the peak values of hardness and Young's modulus decrease rapidly from 1.72 GPa and 31.53 GPa of 0.2 dpa to 1.32 GPa and 25.91 GPa. The increase of the hardness and Young's modulus is due to the micro-crack closure and the increase of matrix defects in graphite caused by irradiation. The sharp decrease of the hardness and Young's modulus at 180℃ is due to the amorphization of graphite structure caused by irradiation.