位错动力学方法在辐照损伤力学中的应用

核能是人类最理想的清洁能源之一，在世界能源结构中发挥着巨大作用。核裂变或核聚变导致的辐照环境会引起材料的辐照损伤，进而显著影响材料的力学性能，造成辐照硬化、脆化、蠕变、肿胀等现象。无论是预测辐照材料的服役寿命，还是设计新型的抗辐照材料，都迫切需要建立强辐照环境下的塑性力学和损伤力学理论。分子动力学方法为理解辐照材料中的原子级相互作用机理提供了诸多有价值的信息，然而受限于时空尺度难以直接用于力学理论模型的建立。晶体塑性有限元方法可用于预测辐照材料的力学响应，但是往往需要基于已知的物理模型，并且拟合实验数据。位错动力学方法是联系纳米力学与连续介质力学的桥梁，是揭示大量微结构的累积相互作用机理，建立基于物理机制的塑性力学和损伤力学理论的强有力手段。位错动力学方法起源于上个世纪八十年代，起初主要用于研究位错间的短程和长程相互作用、计算位错运动引起的塑性变形、硬化、软化、变形局部化等。本文将展示三种耦合位错动力学和辐照损伤场的方法，并系统地综述研究者近年来使用该方法在理解辐照硬化、塑性变形局部化、晶界效应、温度效应、和发展多尺度耦合方法等方面取得的进展。

Application of Dislocation Dynamics Method in Irradiation Damage Mechanics

Nuclear energy is one of the most ideal energy for humans and plays an important role in the world's power supply. Irradiation, induced by nuclear fission or nuclear fusion, causes damage in materials. This significantly affects the mechanical properties of materials, leading to irradiation hardening, embrittlement, creep, swelling and other phenomena. It is urgent to establish the theory of plasticity mechanics and damage mechanics under extreme irradiation conditions, in order to predict the service life of irradiated materials and design new irradiation resistant materials. Molecular dynamics provides numerous valuable information for understanding atomic-level interaction mechanisms in irradiated materials. However, it is difficult to establish mechanical theoretical models directly, due to the limitation of the considered temporal and spatial scale. Crystalline plastic finite element method can be used to predict the mechanical response of irradiated materials, but this kind of method is based on given physical models, and needs to obtain parameters through fitting experimental data. On the other hand, dislocation dynamics method connects nanomechanics with continuum mechanics. For large quantities of microstructures, it is a powerful method to reveal their cumulative interaction mechanisms, making it possible to establish the theory of plasticity mechanics and damage mechanics based on physical mechanisms. Dislocation dynamics method originated in the 1980s. At first, it was mainly used to study the short-range and long-range interactions between dislocations, and calculate the plastic deformation, hardening, softening, and plastic flow localization caused by dislocation movement. This article will summarize three methods of coupling dislocation dynamics and irradiation damage field, then gives a systematic overview about the recent studies of irradiation hardening, plastic flow localization, grain boundary effects, temperature effects through this method.