辐照中氢氦致裂纹韧脆转变的机理研究

项目名称： 辐照中氢氦致裂纹韧脆转变的机理研究

项目编号： No.11475046

项目类型： 面上项目

立项/批准年度： 2015

项目学科： 数理科学和化学

项目作者： 王月霞

作者单位： 复旦大学

项目金额： 65万元

中文摘要： 氢、氦导致结构材料的脆性缩短其使用寿命是发展核能始终无法规避的问题。对该问题的研究由来已久。尽管目前已提出多种致脆机理，然而仍没有得到共识和有效的解决方式。其中较为重要的原因在于：在辐照条件下，氢、氦与基体内移位损伤产生的各种缺陷相互作用形成了尺寸、浓度分布不一的缺陷复合体，这使得基体内的微观状态更为复杂，导致材料在力学等方面呈现不稳定性。本课题拟采用蒙特卡洛、分子动力学以及第一性原理在不同层次研究辐照条件下氢脆、氦脆机制。通过裂纹扩展动力学过程，探讨缺陷复合体诱发材料韧脆转变机制。从电子结构出发研究裂纹尖端原子间键合特征，探寻材料脆性断裂的本质根源。这有助于深入理解材料的致脆机理，并为找到增韧材料的有效办法或探寻新型抗辐照候选材料提供理论依据。

中文关键词： 辐照损伤；微观缺陷；氢；氦；脆性

英文摘要： Helium and hydrogen will induce embrittlement in structural materials, which is an unevadable problem in the development of nuclear energy. The problem has been proposed for long time. It however has not been solved yet. Although many explanations associated with embrittlement have been proposed, people have not gotten to common sense, therefore, no available methods can be found to evidently improve the helium or hydrogen embrittlement of materials. One important reason is that defect complexes are generated under irradiation damage through synergic interaction between helium (or hydrogen) and displaced defects produced by neutron irradiation. The sizes and the distributions of density are different for these defect complexes in the materials, which cause the mechanical properties of materials unstable. In this project, we will reveal the helium (and hydrogen) embrittlement mechanism of structural materials in different atomic levels using Monte Carlo, molecular dynamics and the first principle method, respectively. We will study the dynamic process of micro-crack propagation to discover the mechanism of ductile-brittle transition of materials associated with the defect complexes. And we will elaborate the foundational origination of material rupture through the detailed analysis of chemical bonds between atoms in the front of micro-crack from the viewpoint of electronic structure. We believe that our investigation will definitely contribute to the deep understanding about the embrittlement mechanism, and to provide reference data for experimental scientists to enhance the toughness of structural materials, and further to explore advanced candidate material with high anti-irradiation performance.

英文关键词： Irradiation damage;Micro-defect;Hydrogen;Helium;Embrittlement