金属钨级联碰撞中势函数的影响

Influence of Interatomic Potential on Collision Cascade in Tungsten

原子间相互作用势函数的精确性会影响分子动力学级联碰撞模拟结果的精确性。本文选取5种典型的金属钨势函数进行比较测试,通过分子动力学方法,用能量为10 keV和50 keV的初级碰撞原子进行级联碰撞模拟,讨论和分析了辐照过程中缺陷的产生、缺陷团簇和位错环的分布。结果表明:对于最终稳定状态下的弗兰克尔对的数目,不同势函数的模拟结果没有明显差别,而对于缺陷的空间分布、缺陷团簇分数及位错环的分布,不同势函数的模拟结果各有特点。本文结果为用于辐照级联模拟势函数的选择提供了参考,也为钨基势函数的进一步优化提供了指导。

The accuracy of interatomic potential will affect the accuracy of the molecular dynamics collision cascade simulation results.In this work,five typical interatomic potentials for tungsten were selected for comparison in neutron collision cascade simulations at the primary knock-on atom energy of 10 keV and 50 keV by molecular dynamics methods.The generation of defects,the distributions of defect clusters and dislocation loops in cascades were systematically analyzed and discussed.The results show that the simulation results of the number of Frenkel defect pairs for different potentials are not significantly different in the final stable state,but the spatial distribution of defects,defect cluster fractions and the distribution of dislocation loops for different potentials have their own characteristics.The current results provide a reference for selecting potentials in irradiation cascade simulations,and a guidance for the further optimization of the interatomic potential in tungsten.