晶界对离子辐照下纳米Gd2Zr2O7损伤行为的影响机制

项目名称： 晶界对离子辐照下纳米Gd2Zr2O7损伤行为的影响机制

项目编号： No.11505122

项目类型： 青年科学基金项目

立项/批准年度： 2016

项目学科： 数理科学和化学

项目作者： 齐建起

作者单位： 四川大学

项目金额： 25万元

中文摘要： 作为材料中晶粒与晶粒的连接区域，晶界在辐照损伤行为中起着至关重要的作用，而目前晶粒减小(晶界面积增加)对抗辐照加固或减弱行为仍存在较大分歧。在对核废物最佳地质处置方式的人造岩石(陶瓷)晶格固化研究中，Gd2Zr2O7由于对高放锕系元素或后处理后核废物的高包容性、高耐辐照性能(>100dpa下未发生非晶化)和高化学稳定性是最佳优选材料体系。目前研究重点主要集中于采用强离子加速辐照来探知入射离子造成材料内的各辐照损伤行为，从而对固化核素自发衰变所致固化体的辐照损伤和安全性评估，然而晶界对纳米Gd2Zr2O7辐照损伤行为的影响还未开展相关研究。本项目基于前期采用SPS和UHPLT方法获得的纳米Gd2Zr2O7，拟采用He2+辐照，研究晶界对辐照致相变、辐照致缺陷的产生和聚集、辐照致肿胀等损伤行为的影响规律和机制。在此基础上提出抗辐照加固晶界设计方案，为核废物地质处置的安全性提供理论和技术基础。

中文关键词： Gd2Zr2O7；纳米陶瓷；晶界；辐照损伤；机理研究

英文摘要： The internal microstructures, especially grain boundaries, have significant impacts on radiation damage and radiation stability of ceramic materials. The enhanced or restrained radiation resistance effects of grain boundary in many materials with nano-structure has been reported. The effects are spically important on a form of synthetic rock, SYNROC, which is composed of mutually compatible phases and possess crystal structures identical to chemical durable minerals and was proposed as the most promising host phases for immobilization of actinides and fission products. Gd2Zr2O7 with pyrochlore structure, which is chemical durable, radiation resistant(critical amorphization dose is higher than 100dpa), and have high tolerance of nuclear waste, is one of its candidate component phase. Currently, many studies focus mainly on using ion irradiation under accelerator or TEM to simulate the self-irradiation of the solidified radioactive nuclear waste elements to study the radiation damage in host phases and assess its safety, but no studies reported for Gd2Zr2O7 nanoceramic. On the basis of the synthesized Gd2Zr2O7 nanoceramic by SPS method and Ultrahigh pressure and low temperature sintering method, we would carry out the He2+ irradiation experiments to study the swelling, generation and accumulation of the defects, and phase transformation induced by irradiation. A grain boundary design for enhanced irradiation resistance will be proposed in our study to provide theoretical and technical foundation for the security of nuclear waste geological disposal.

英文关键词： Gd2Zr2O7;nanocrystalline ceramics;grain boundary;irradiation demage;mechanism