LBE/辐照协同作用对SiC/SiC复合材料的损伤机理研究

SiC/SiC复合材料具有抗辐照、耐高温、耐腐蚀等优良特性，是聚变、裂变用关键材料之一，例如在ADS系统和铅冷快堆中。在服役期间，SiC/SiC复合材料面临强中子辐照、高温液态铅铋腐蚀、冲刷等极端环境考验。已有研究发现辐照能够加速腐蚀，可能原因是辐照产生的空位和间隙子改变了材料能带结构，导致载流子迁移率发生变化，但具体原因尚待进一步研究。因此，本项目将利用兰州重离子国家实验室SFC加速器提供的快重离子，结合已搭建的国内首台在线辐照-液态重金属腐蚀研究平台，开展SiC/SiC复合材料重离子辐照、铅铋腐蚀协同效应研究。通过综合分析现有实验数据，借助辐照损伤理论、液态金属腐蚀模型和理论模拟，探讨微观缺陷与铅铋金属、氧原子相互作用关系，并建立辐照作用下铅铋腐蚀SiC/SiC复合材料损伤模型。期望通过努力，为SiC/SiC复合材料在ADS系统和铅冷快堆中的应用提供重要的数据和科学依据。

Due to their supeior radiation resistance, mechanical properties at high temperature and excellent corrosion resistance, SiC fiber-reinforced SiC-matrix composites (SiC/SiC) are considered as primary candidate materials used in fusion and fission power systems. In Accelerator Driven Subcritical System (ADS) and lead-cooled fast reactor, SiC/SiC composites have been used as an important structural material. In severe environments such as lead-bismuth eutectic (LBE), these materials, however, suffer from an intense radiation-accelerated high-temperature corrosion. It is, therefore, worth investigating synthesis effects of high-flux ion irradiation and LBE corrosion simultaneous on the damage evolution of SiC/SiC composites. Previously published research on this phenomenon indicates that the creation of defect-localized states inside the bandgap, inducing the change of the electrically active defects, is to a large extent responsible for the accelerated corrosion. Yet a comprehensive understanding of the involved processes still poses a great theoretical and experimental challenge. This project proposes high-energy heavy ion irradiation of SiC/SiC composites utilizing the Sector Focusing Cyclotron of Heavy Ion Research Facility in Lanzhou (HIRFL-SFC), combined with LBE corrosion environment of an advanced heavy liquid metal facility. The main goal of the proposed research is to establish a model of defect nucleation and growth in SiC/SiC composites by combining the theory of swift heavy ions irradiation effects, and LBE corrosion mechanism with the experimental results obtained by advanced characterization methods. The aim study is to explain the interaction between microstructural defects and oxygen, lead and bismuth. Building on our previous investigations, we expect to provide new important data which can potentially improve the understanding of the limiting aspects of the application of SiC/SiC composites in ADS and lead-cooled fast reactors through our effects.