位错环上的Cr偏析对辐照硬化影响的原子尺度模拟研究

低温辐照脆化是影响低活化铁素体/马氏体（RAFM）钢服役的主要问题之一。RAFM钢低温辐照脆化的主要机理是辐照产生的纳米缺陷（如位错环、析出物等）阻碍位错运动。本文利用分子动力学方法研究了bcc-Fe内刃型位错线与1/2〈111〉间隙位错环的相互作用，并对比分析了Cr偏析在位错环上对其硬化的影响。研究结果表明：刃型位错线挣脱位错环所需临界剪切应力（CRSS）与位错环的伯格斯矢量有关；在本文所研究条件下，在一定温度范围内，Cr偏析在位错环上会使得位错线挣脱所需CRSS增加，引起硬化增强。

Atomic Scale Simulation Research on Effect of Cr Segregation at Dislocation Loop on Irradiation Hardening

Lower temperature irradiation embrittlement is one primary issue limiting the use of reduced activation ferritic/martensitic (RAFM) steels. The primary mechanism of lower temperature irradiation embrittlement is the obstruction of dislocation motion by nano-metric defects, such as dislocation loop and precipitation, induced by irradiation. Using molecular dynamics, the interaction mechanism between edge dislocation line and 1/2〈111〉 interstitial dislocation loop in bcc-Fe was studied, and the effect of Cr segregation at interstitial dislocation loop on irradiation hardening was analyzed. The results show that the critical resolved shearing strain (CRSS) for dislocation line to break away from loop is related with the Burgers vector (BV) of loop. Under the condition studied here, within a certain temperature range, Cr segregation at loop increases the CRSS for dislocation line to break away, thus enhances hardening.