【作者】 孙剑；

【导师】 王雪林； 刘泳；

【作者基本信息】 山东大学 ， 凝聚态物理， 2023， 硕士

【摘要】 核能在世界能源供应上起到重要作用,对核能材料的性能提出了更加苛刻的要求,使得对核能材料的辐照效应研究变得更为迫切。FeCrAl具有的耐腐蚀性、抗辐照性、耐高温氧化性和抗应力腐蚀开裂性等优良性质,被认为是最有前途的事故燃料包壳材料之一,而B4C是一种具有优良性能的功能陶瓷材料,特别是具有较高的热中子吸收能力,常用于核反应堆的控制棒材料及核屏蔽材料等领域。该论文以FeCrAl和B4C为研究对象,基于兰州重离子加速器国家实验室的低能量强流高电荷态重离子研究装置(LEAF),开展MeV级别以上能区的He、Fe离子辐照,以及TEM等微结构分析表征、纳米压痕等力学性能分析;并以Nix-Gao等物理模型为基础,从实验及理论上探究离子辐照环境下,材料力学性能演化机理。主要研究内容和研究结果为:利用He离子对FeCrAl进行辐照并探究结构变化和力学性能,在辐照损伤区内只发现了大量的黑点缺陷,并且FeCrAl辐照硬化,证明了黑点缺陷对辐照硬度不能忽略的贡献;利用Fe离子对FeCrAl辐照,发现辐照表面出现了大量凸起的圆形小丘结构,发现了其结构中存在偏析行为并使得合金硬度下降。后续探索了 FeCrAl成分与辐照硬化之间的关系,发现当Al含量为4 wt%时,Cr含量为17 wt%时FeCrAl辐照硬化程度最高。利用不同条件的He离子和Fe离子对B4C进行辐照,发现但单独He离子辐照对于B4C的损伤和硬度几乎没有影响;单独Fe离子或He-Fe混合束流辐照对B4C造成了较大的损伤,并且使得B4C硬度明显下降,He-Fe混合束流辐照由于协同效应,影响最显著。相应结果期望对反应堆材料辐照损伤研究提供科学参考,促进我国核能安全、高效地发展和应用。更多还原

【Abstract】 Nuclear energy plays an important role in global energy supply and puts more stringent requirements on the performance of nuclear materials,making research on the radiation effects of nuclear materials more urgent.FeCrAI has excellent properties such as corrosion resistance,radiation resistance,high-temperature oxidation resistance,and stress corrosion cracking resistance,and is considered one of the most promising accident fuel cladding materials.B4C is a functional ceramic material with excellent properties,especially high thermal neutron absorption capacity,commonly used in the control rod materials and nuclear shielding materials of nuclear reactors.This paper studies FeCrAI and B4C.conducts He and Fe ion irradiation in the MeV energy range and above based on the Low Energy intense-highly-charged ion Accelerator Facility(LEAF)at the National Laboratory of Heavy Ion Research Facility in Lanzhou,and characterizes the microstructure using TEM and analyzes the mechanical properties using nanoindentation.Based on the physical models of Nix-Gao and other researchers.the paper explores the evolution mechanism of mechanical properties of materials under ion irradiation in both experimental and theoretical aspects.The main research content and results:Explored the structural changes and mechanical properties of FeCrAI by He ion irradiation,only a large number of black-dot defects were found in the irradiation damaged area and FeCrAI was hardened by irradiation which proved that the contribution of black-dot defects to the irradiation hardness cannot be ignored.Irradiated FeCrAl by Fe ions,it was found that a large number of small billock structures appeared on the irradiated surface,and it was found that there was segregation behavior in the structure and the hardness of the alloy decreased.The relationship between FeCrAI composition and radiation hardening was subsequently explored,and it was found that when the AI content was 4 wt%,the FeCrAI radiation hardening degree was the highest when the Cr content was 17 wt%.B4C was irradiated with different conditions of He ions and Fe ions,and it was found that the single He ion irradiation had little effect on the damage and hardness of B4C;The larger damage is caused,and the hardness of B4C is obviously reduced,and the He-Fe mixed beam irradiation has the most significant effect due to the synergistic effect.更多还原