用正电子湮没谱学研究辐照缺陷的自修复机理

项目名称： 用正电子湮没谱学研究辐照缺陷的自修复机理

项目编号： No.11275142

项目类型： 面上项目

立项/批准年度： 2013

项目学科： 数理科学和化学

项目作者： 王柱

作者单位： 武汉大学

项目金额： 90万元

中文摘要： 先进核能系统的发展依赖于人们对反应堆材料的辐照损伤过程的进一步了解。本项目以纳米结构材料的缺陷自修复行为为背景，采用正电子湮没寿命谱和符合多普勒展宽谱、高分辨电子显微镜、加速器-电镜联机、X射线衍射等分析手段，并结合第一性原理计算和分子动力学模拟，研究几种材料的辐照效应,以及晶粒大小和抗辐照能力的关系；分析电子、质子和氦离子辐照缺陷种类、大小、浓度。研究单质材料晶界和复合材料中双相界面对缺陷形成能、缺陷迁移势垒的影响和差别。探索纳米材料的辐照缺陷自修复行为的物理机制。通过计算机模拟和理论推导，研究纳米材料中电子辐照缺陷的产生、迁移和湮灭的演化规律,了解不同辐照剂量率条件下材料结构的变化；研究氢和氦协同作用下纳米材料的辐照效应及辐照缺陷产生、迁移与湮灭机理。本项目研究结果对探索新型抗辐照材料研究提供重要的实验数据和理论依据，对新型核能系统结构材料设计有重要意义。

中文关键词： 缺陷；自修复；晶界；纳米材料；正电子湮没

英文摘要： Developing advanced nuclear energy systems depends crucially on the improved understanding of radiation-damage processes in reactor materials. With the background of self-healing of the radiation-induced damage, we will study the radiation effects and the dependence of resistance to irradiation damage on specific area of grain boundaries by the experiment methods of positron annihilation lifetime spectroscopy and coincident Doppler braodening spectroscopy, high-resolution electron microscopy, united equipment of accelerator-electron, X-ray diffraction, and by theoretical calculation of first-principles and molecular dynamics simulations. Analyse the type, size, concentration of defects in samples induced by electron irradiation, proton irradiation and helium ion implantation. The effects of the grain boundaries in single- and two-phases materials on defect formation energy and migration barrier will be studied. Research the mechanism of defects self-healing phenomenon. The evolution from production, migration to recombination of irradiation defects can be researched with computer simulation in order to understand structure in materials under a various of irradiations. We can deduce the equilibrium concentration of defects during irradiation. We will research the irradiation defect structure and the mechanism of

英文关键词： defects；self-healing；grain boundary；Nanomaterials；positron annihilation