辐照导致奥氏体不锈钢内位错环演化行为模拟

Modeling of Evolution of Radiation-induced Frank Loops in Austenitic Stainless Steels

为了描述和预测奥氏体不锈钢材料在辐照条件下位错环的演化行为,本文基于平均场速率理论结合分子动力学方法建立辐照诱导奥氏体不锈钢内位错环演化的物理模型,模拟电子、中子辐照诱导奥氏体不锈钢内位错环的演化行为,模拟结果与实验结果吻合很好。在此基础上探究了中子辐照产生的存活缺陷对材料内位错环演化行为的影响,研究表明级联碰撞过程中的缺陷存活率、缺陷成团率以及四间隙原子团簇所占的团簇份额是影响位错环演化行为的主要参数,而双间隙原子团簇份额和三间隙原子团簇份额之间比例对位错环的演化没有影响。

This work mainly focuses on the evolution mechanism of Frank loops in austenitic stainless steels under neutron irradiation by computer simulation. Molecular dynamics and mean field rate theory were employed. Firstly, a rate theory model was constructed to model the evolution of the neutron irradiation induced Frank loop in austenitic steels; Secondly, this model was parameterized by molecular dynamics simulation, and the model was validated by comparing the simulation results of dislocation loops with the experimental data in steels under electron and neutron irradiation conditions. Based on our results, the effect of survival defects under cascade collision was studied, and the survival fraction, the cluster fraction of defects and the fraction of 4-interstitials-clusters are the mainly factors for the evolution of Frank loops. The fraction of interstitial clusters which size are smaller than 4 has no effect on the Frank loop evolution under neutron irradiation.