金红石辐照损伤的分子动力学模拟

Irradiation Damage in Rutile by Molecular Dynamics Simulation

为了研究辐照条件下金红石的耐辐照损伤能力,采用GULP软件包拟合出了与实验值吻合的势函数,并采用LAMMPS软件包计算出了金红石的离位阈能和高能粒子反冲条件下的位移级联。通过统计球坐标系下266个出射方向的离位能,利用缺陷形成概率的定义得出Ti和O原子的离位阈能分别为(78.3±1.0)eV和(42.6±2.0)eV。采用VORONOI缺陷统计方法,计算了300 K、10 keV出射能量条件下缺陷数量随辐照时间演化信息,结果表明:Ti原子作为初始出射原子产生的缺陷数量整体高于O原子产生缺陷的数量,在最大无序阶段产生的空位、填隙和不同类型反位缺陷通过空位-填隙复合作用和kick-out机制逐渐减少,有效地降低了晶体的无序度,提高了基材耐辐照损伤性能。

In order to study the radiation damage resistance of rutile under irradiation conditions,the GULP software package was used to fit the potential function consistent with the experimental values,and the threshold displacement energies and displacement cascades were calculated by LAMMPS software package.By calculating the threshold displacement energies of 266 directions in the polar coordinate system,using the definition of defect formation probability,threshold displacement energies of Ti and O atoms were obtained,which are(78.3±1.0)eV and(42.6±2.0)eV,respectively.Using VORONOI defect statistical method,the numbers of defects with the irradiation time of 300 K and 10 keV was calculated.The results show that the total number of defects generated by Ti atoms is higher than that of O atoms.The vacancies,interstitials and different types of antisite defects generated in the maximum disordered phase are gradually reduced by the vacancy-interstitial compounding and kick-out mechanism,which effectively reduces the disorder of the crystal and improves the radiation damage resistance of the substrate.