液态锂腐蚀对铁力学性能影响的多尺度分析

项目名称： 液态锂腐蚀对铁力学性能影响的多尺度分析

项目编号： No.11472273

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： 余新刚

作者单位： 中国科学院大学

项目金额： 90万元

中文摘要： 聚变堆环境下，液态锂对结构材料不锈钢的腐蚀一直是被广泛关注的问题。腐蚀可引起材料微观结构的变化，进而影响材料的宏观力学性能，给聚变装置的安全性带来严重威胁。目前相关研究尚不充分。鉴于此，本项目拟以α-Fe为研究对象，在构造Li-Fe相互作用势函数的基础上，对Li-Fe相互作用的微观过程进行数值模拟，分析温度、液态锂流速等外界环境因素以及α-Fe晶体结构、杂质等内在因素对腐蚀过程的影响规律，探索液态Li腐蚀α-Fe的微观机理；利用代表体积元的概念，对含腐蚀缺陷的α-Fe进行多尺度表征和建模，通过发展新的分子动力学/有限元耦合多尺度计算方法，模拟分析腐蚀后α-Fe在典型工况下的力学行为，计算弹性模量、屈服应力、断裂韧性、断裂应变等关键力学参数，揭示腐蚀对α-Fe宏观力学性能的影响规律和内在机制。目标是为聚变装置中液态锂偏滤器的工程应用提供科学依据。

中文关键词： 液态锂偏滤器；腐蚀；力学性能；多尺度

英文摘要： The corrosion of liquid lithium on structural stainless steel has been a critical issue of fusion reactors for over three decades. The modification of the microstructure caused by corrosion will significantly change the macroscopic mechanical properties of stainless steel and challenge the safety of fusion devices. Up to now, the undergoing mechanism is still not well understood. Therefore, we present this proposal where the atomic interaction potential between Li-Fe will be constructed and used to simulate the microscopic process of the corrosion of lithium on α-Fe. The defects inside α-Fe grains and lattices will be traced. The influence of external environmental factors, such as temperature and the velocity of flowing liquid lithium, as well as the internal factors, such as the lattice structure, grain boundaries and impurities, will be analyzed to reveal the micro-mechanism of corrosion. Meanwhile, the multi-scale modelling of α-Fe material containing corrosive defects will be performed by employing the concept of representative volume element. A new multi-scale method connecting molecular dynamics and finite element method will be developed. Through this method, the macroscopic mechanical behavior of α-Fe under classic loads will be simulated. The Young's modulus, yield stress, fracture toughness and fracture stain will be computed. The mechanism of how corrosion of Li influences the mechanical properties of α-Fe will be investigated. The purpose of this project is to provide scientific support for application of liquid lithium divertor in future fusion devices.

英文关键词： Liquid lithium divertor;corrosion;mechanical properties;multi-scale