Materials Science & Technology Division, Oak Ridge National Laboratory, 4500S (A148), MS 6138, Oak Ridge, Tennessee 37831-6138, USA.
Phys Chem Chem Phys. 2012 Oct 14;14(38):13429-36. doi: 10.1039/c2cp42342a.
Radiation tolerance is determined by how effectively the microstructure can remove point defects produced by irradiation. Engineered nanocrystalline SiC with a high-density of stacking faults (SFs) has significantly enhanced recombination of interstitials and vacancies, leading to self-healing of irradiation-induced defects. While single crystal SiC readily undergoes an irradiation-induced crystalline to amorphous transformation at room temperature, the nano-engineered SiC with a high-density of SFs exhibits more than an order of magnitude increase in radiation resistance. Molecular dynamics simulations of collision cascades show that the nano-layered SFs lead to enhanced mobility of interstitial Si atoms. The remarkable radiation resistance in the nano-engineered SiC is attributed to the high-density of SFs within nano-sized grain structures that significantly enhance point defect annihilation.
辐射耐受性取决于微结构去除辐照产生点缺陷的效率。具有高密度位错（SFs）的工程纳米晶 SiC 极大地增强了间隙原子和空位的复合，从而实现了辐照缺陷的自修复。虽然单晶 SiC 很容易在室温下发生辐照诱导的晶态到非晶态的转变，但具有高密度 SFs 的纳米工程 SiC 的抗辐射能力提高了一个数量级以上。碰撞级联的分子动力学模拟表明，纳米层状 SFs 导致间隙 Si 原子的迁移率增强。纳米工程 SiC 的显著抗辐射能力归因于纳米晶粒结构中高密度的 SFs，这极大地增强了点缺陷的消除。
