辐照条件下纯金属及其合金材料的力学性能研究

In terms of the pure metals and alloys, we analyze the irradiation effect on the mechanical properties at micro-, meso- and macro-scale, which mainly include irradiation hardening, embrittlement, creep and fatigue by three methods (i.e., experimental testing, theoretical prediction and numerical simulation). First, at the micro-scale, the detailed processes of defect formation are simulated by several numerical simulation methods like molecular dynamics simulation, which can help understand the relationship between radiation parameters and the defects information. The corresponding results can be effectively compared with experimental results. Then, at meso-scale the interaction between dislocations and defects will be investigated by the dislocation dynamics. A theoretical model concerning micro-, meso- and macro-scales based on the finite element simulation, self-consistent method and the crystal plasticity theory is established. Finally, the generality and accuracy of the proposed multi-scale model are validated by comparing with the corresponding experimental results. This project aims at predicting the mechanical behaviors of irradiated metals, and has a great significance for designing anti-irradiation materials. Furthermore, this project will pave the way to the mechanism analysis and the improvement of the material performance of China Low Activation Martensitic (CLAM) steel.

本项目拟针对纯金属及合金材料，通过实验表征、数值模拟、理论建模三种研究手段，从微观尺度、细观尺度和宏观尺度开展辐照硬化、脆化、蠕变以及疲劳四个方面的研究。首先，通过分子动力学等多种模拟计算手段，从微观尺度模拟分析金属材料中缺陷的形成过程，建立辐照率、辐照剂量等与缺陷种类和数量之间的定量关系，并与实验测量的缺陷信息结果比较。然后，基于细观尺度的位错动力学开展缺陷与位错的相互作用研究，以晶体塑性理论为桥梁，通过有限元模拟、细观力学等方法建立微、细、宏观之间的跨尺度理论框架。最后，基于力学实验的测试结果，验证其合理性。本项目的研究为预测材料性能演化规律、设计具有良好性能的抗辐照材料提供可靠的依据和支撑，也为具有自主知识产权的中国低活化马氏体钢（CLAM钢）机制分析和力学性能进一步优化奠定基础。

本项目主要研究辐照条件下纯金属及其合金材料的力学性能变化，通过实验、模拟、理论等方法，从微观-细观-宏观等不同尺度揭示了辐照缺陷、位错、晶界等微观结构对金属材料力学性能的影响，包括辐照硬化、脆化、蠕变以及疲劳。在此基础上建立了描述不同辐照剂量、温度、样品尺寸下材料力学性能的多尺度理论模型，实现了核辐照下典型纯金属及合金力学性能理论预测，为国产核聚变堆结构材料(中国低活化马氏体钢)辐照性能预测和优化提供理论基础。在本项目执行期间，在Phys. Rev. Lett.，J. Mech. Phys. Solids, Int. J. Plasticity, Int. J. Solids Struct., J. Nucl. Mater., 等国际著名杂志上发表SCI论文38篇，授权专利6项，参加国内外学术会议30余次，并受邀做大会/半大会报告、主旨报告和特邀报告10余次，主持承办学术会议10余次。获得17项学术奖励，包括国家自然科学二等奖（2020）（具有界面效应的复合材料细观力学研究，获奖人：段慧玲，王建祥，黄筑平），美国机械工程师学会会士（ASME Fellow）（2020），国家“万人计划”领军人才（2017）。