纳晶碳化硅中辐照缺陷在氢氦协同作用下演变机制的理论模拟研究

项目名称： 纳晶碳化硅中辐照缺陷在氢氦协同作用下演变机制的理论模拟研究

项目编号： No.11305122

项目类型： 青年科学基金项目

立项/批准年度： 2014

项目学科： 数理科学和化学

项目作者： 张鹏

作者单位： 西安交通大学

项目金额： 28万元

中文摘要： 纳晶碳化硅中细小的晶粒和更多的晶界可能表现出对辐照缺陷自愈合的优良特性从而大大提高其抗辐照能力，这最近引起了国内外专家学者的强烈关注。本项目采用理论模拟方法对氢氦协同作用下纳晶碳化硅中辐照缺陷演变机制开展基础研究。首先基于第一性原理计算数据开创性地拟合氢氦碳硅原子间相互作用势；然后采用经典分子动力学和独立开发的温度加速分子动力学，对氢氦协同作用在不同类型晶界和各种纳米晶粒的碳化硅中典型缺陷结构演化进行长时间毫秒级的模拟；最后将相关结果利用速率理论根据缺陷产生和转化的竞争平衡关系建立缺陷演化动力学方程，实现对复杂缺陷微结构在更长时间秒级以上演化出现关键临界状态的预测。本项目将从微观角度深刻认识纳晶材料中辐照缺陷结构受氢氦协同作用产生的新现象、新规律，前瞻性地为我国三束辐照大型基础科学装置的实验开展提供有力参考。这将为我国在核聚变领域关键材料的设计评价提供具有重大意义的基础数据积累和理论指导。

中文关键词： 3C-SiC；理论模拟；缺陷结构演变；氢氦效应；材料性能

英文摘要： Nanocrystalline silicon carbide with tiny grains and many grain boundaries could improve the irradiation resistance outstandingly due to the capability of self-healing on the irradiation induced defects. It has recently stimulated the strong concerning on this kind of material from many experts both at home and abroad. We carry out the basic research project on the synergistic mechanism of hydrogen and helium for irradiation defects evolution in nanocrystalline silicon carbide in the use of theoretical simulations. First, we initiatively develop the hydrogen-helium-carbon-silicon interatomic potential based on the results data from the first-principles calculations. Second, the typical defect structure evolutions in different kinds of grain boundaries and various nano-grains of silicon carbide considering the synergistic effects of hydrogen and helium are simulated in the time scale around pico seconds using the classical molecular dynamic and the independently developed temperature accelerated molecular dynamic method. Finally, in the frame of rate theory based on the competition between defect production and transformation, the kinetic equations of defect evolution will be established with relevant results obtained before to realize the prediction of the critical states of complex defect structures during the

英文关键词： 3C-SiC；Theoretical simulation；Evolution of defect sturcture；Effect of Hydrogen and Helium；Material Property