兰州大学机构库 >物理科学与技术学院
用第一性原理计算研究M3AX2相材料的点缺陷
Alternative TitleInvestigation of point defects by first-principles calculations in M3AX2 materials
邱烨
Thesis Advisor杨磊
2015-05-28
Degree Grantor兰州大学
Place of Conferral兰州
Degree Name硕士
Keyword第一性原理 MAX相 空位 间隙原子
Abstract本篇论文利用第一性原理计算方法,通过计算M3AX2相材料的点缺陷,达到研究其结构稳定性和抗辐射性能的目的。本篇论文的研究对象是M3AX2相材料中Ti3AlC2、Ti3SiC2、Ti3GeC2和Ta3AlC2这四种化合物。通过对计算结果进行分析讨论了在辐照条件下,空位型点缺陷对这四种材料的晶体结构的影响。本文首先计算了Ti3AlC2材料的晶胞参数,和实验上测得的结果一致,确保了本次计算的准确性。接下来计算了这四种材料的弹性常数和弹性模量,证明其晶体结构能够稳定存在,并对其原子间相互作用和键合强度有了初步判断。在此基础上,本篇论文计算了这四种材料中每种元素的单空位形成能和空位迁移能,通过对计算结果进行分析,得出一个结论,M3AX2结构中M原子层(包括M1和M2)最不活跃,在辐照条件下最不易出现空位,其中,靠近A原子层的M2原子层更活跃。为进一步验证这一结论,本文计算了态密度和电荷密度,从原子间相互作用和键合强度两方面对结论做详细分析。同时发现,空位对M3AX2相材料导电性的影响可以忽略不计。本文还计算了Ti3SiC2材料的氦间隙子成能,包括单间隙子和双间隙子。计算结果表Ti3SiC2材料具有良好的抗辐射性能,间隙子形成能的大小与间隙原子所占的位置关。本篇论文通过对计算得到的结果行分析,讨论了M3AX2相材料的结构稳定性和抗辐射性能。
Other AbstractThe point defect of M3AX2 phases have been calculated using first-principles calculations.The aim of the calculations is explore structural stability and irradiation resistance of M3AX2 phases materials.M3AX2 phases materials includes Ti3AlC2、Ti3SiC2、Ti3GeC2 and Ta3AlC2. The results of calculations clarify that vacancy defect is of great significance in terms of crystal structure under irradiation. Firstly,we calculated lattice parameters of Ti3AlC2 material. The result is consistent with the experimental results and ensure the accuracy of this calculation. Secondly,we calculated elastic constants and elastic modulus of M3AX2 phases materials.The results prove their stability and preliminary estimate their interaction and bonding between atoms. Based on previous conclusions,the formation and migration energies of the mono-vacancies in M3AX2. By analyzing the results,we draw an important conclusion that M atomic layer (including M1 and M2) is the lowest active.M vacancy was found to preferentially form in the M2 layer close to A layer.Density of state and electron density were calculated to verify the conclusion from interaction and bonding between atoms. The formation energy of helium interstitial atom (mono-interstitial and bi-interstitial) was calculated.Ti3SiC2 material has a better irradiation resistance because of the higher formation energy.The above results contribute to study structural stability and irradiation resistance of M3AX2 materials.
URL查看原文
Language中文
Document Type学位论文
Identifierhttps://ir.lzu.edu.cn/handle/262010/229071
Collection物理科学与技术学院
Recommended Citation
GB/T 7714
邱烨. 用第一性原理计算研究M3AX2相材料的点缺陷[D]. 兰州. 兰州大学,2015.
Files in This Item:
There are no files associated with this item.
Related Services
Recommend this item
Bookmark
Usage statistics
Export to Endnote
Altmetrics Score
Google Scholar
Similar articles in Google Scholar
[邱烨]'s Articles
Baidu academic
Similar articles in Baidu academic
[邱烨]'s Articles
Bing Scholar
Similar articles in Bing Scholar
[邱烨]'s Articles
Terms of Use
No data!
Social Bookmark/Share
No comment.
Items in the repository are protected by copyright, with all rights reserved, unless otherwise indicated.