Bonny G, Buongiorno L, Bakaev A, Castin N
SCK CEN, Nuclear Materials Science Institute, Boeretang 200, B-2400, Mol, Belgium.
Sci Rep. 2020 Jun 26;10(1):10483. doi: 10.1038/s41598-020-67070-x.
Silicon carbide (SiC) and SiC/SiC composites are important candidate materials for use in the nuclear industry. Coarse grain models are the only tools capable of modelling defect accumulation under different irradiation conditions at a realistic time and length scale. The core of any such model is the so-called "source term", which is described by the primary damage. In the present work, classical molecular dynamics (MD), binary collision approximation (BCA) and NRT model are applied to describe collision cascades in 3C-SiC with primary knock-on atom (PKA) energy in the range 1-100 keV. As such, BCA and NRT are benchmarked against MD. Particular care was taken to account for electronic stopping and the use of a threshold displacement energy consistent with density functional theory and experiment. Models and regressions are developed to characterize the primary damage in terms of number of stable Frenkel pairs and their cluster size distribution, anti-sites, and defect type. As such, an accurate cascade database is developed with simple descriptors. One of the main results shows that the defect cluster size distribution follows the geometric distribution rather than a power law.
碳化硅（SiC）及SiC/SiC复合材料是核工业中重要的候选材料。粗晶粒模型是唯一能够在实际的时间和长度尺度下模拟不同辐照条件下缺陷积累的工具。任何此类模型的核心都是所谓的“源项”，它由初级损伤来描述。在本工作中，应用经典分子动力学（MD）、二元碰撞近似（BCA）和NRT模型来描述能量在1 - 100 keV范围内的初级撞出原子（PKA）在3C - SiC中引发的碰撞级联。因此，将BCA和NRT与MD进行了基准测试。特别注意考虑了电子阻止以及与密度泛函理论和实验一致的阈位移能的使用。开发了模型和回归方法，以便根据稳定弗伦克尔对的数量及其团簇尺寸分布、反位缺陷和缺陷类型来表征初级损伤。这样，就用简单的描述符开发了一个准确的级联数据库。主要结果之一表明，缺陷团簇尺寸分布遵循几何分布而非幂律分布。
