分子动力学研究α-锆晶界对辐照损伤的影响

Molecular Dynamics Study on the Effect ofα-Zr Grain Boundary on Irradiation Damage

运用分子动力学研究距离α-锆晶界(GB)平面不同位置和不同能量PKA(Primary Knock-on Atom)产生的辐照损伤微观缺陷变化,分析了晶界对辐照损伤微观缺陷演化的影响。模拟显示间隙形成能、空位形成能和原子离位阈能在晶界附近随距离晶界平面位置减小而减小,它们在晶界内的大小明显小于晶界外的相应数值结果,其中间隙形成能比空位形成能受晶界的影响更大。在晶界平面上原子的离位阈能没有明显的各向异性。在级联热峰阶段会产生大量的<11-20>密排方向的挤列子。晶界具有强的吸收缺陷的能力,级联碰撞产生的缺陷构型分布与热峰阶段缺陷团和晶界的相对位置密切相关。

Molecular dynamics(MD)was used to study the changes of irradiation-induced microdefects at different distances from theα-Zr grain boundary(GB)plane and different energies of PKA(Primary Knock-on Atom),and the effect of grain boundary on the evolution of irradiation-induced microdefects was analyzed.The simulation results show that the gap formation energy,vacancy formation energy and atomic departure threshold energy near the grain boundary decrease with the decrease of the plane position from the grain boundary,and their size in the grain boundary is significantly smaller than that outside the grain boundary.The gap formation energy is more affected by the grain boundary than the vacancy formation energy.There is no obvious anisotropy in the delocalization threshold energy of atoms on the grain boundary plane.In the cascade hot peak stage,a large number of crowdion in the<11-20>close-packing direction will be generated.The grain boundary has strong ability to absorb defects.The defect configuration distribution caused by cascade collision is closely related to the relative position of defect clusters and grain boundaries in the hot peak stage.