论文标题
β-和α-$ SI_3N_4 $中空位簇形成的分子动力学模拟
Molecular Dynamics Simulation of Vacancy Cluster Formation in β- and α-$Si_3N_4$
论文作者
论文摘要
分子动力学模拟用于研究$β$ - 和$α$ - $ si_3n_4 $的空位群集形成，其空位含量不同（0-25.6 at％）。空缺是在超级电池中随机创建的，随后对114纳秒进行热处理。结果表明，$β$和$α$均可忍受最高12.8的空缺，并形成簇，从而证实了以前的实验数据，表明8％的空缺为$α$ -SI_3N_4 $。但是，$β$中的25.6位空位会导致完全非正式化，而$α$中的数量相同，导致半不形式的$α$相转换为有缺陷的$β$相位，从而导致以新形成的$β$删除簇。这清楚地说明了为什么在$β$中未在$β$中观察到集群空缺，因为$β$ - $ si_3n_4 $ ceramics是由$α$生产的。此外，两种修饰的晶格参数随空缺含量的增加而增加，这揭示了以前以$α$ -SI_3N_4 $ $α$ -SI_3N_4 $报告的不同晶格常数的原因。
Molecular dynamics simulation is used to study vacancy cluster formation in $β$- and $α$-$Si_3N_4$ with varying vacancy contents (0 - 25.6 at%). Vacancies are randomly created in supercells, which were subsequently heat-treated for 114 nanoseconds. The results show that both $β$ and $α$ can tolerate vacancies up to 12.8 at% and form clusters, confirming previous experimental data indicating 8 at% vacancy in $α$-$Si_3N_4$. However, 25.6 at% vacancy in $β$ results in complete amorphization, while the same amount in $α$ results in a transformation of a semi-amorphous $α$ phase to a defective $β$ phase, leading to the removal of the clusters in newly formed $β$. This clearly explains why cluster vacancies are not experimentally observed in $β$, considering that $β$-$Si_3N_4$ ceramics are produced from $α$. Furthermore, the lattice parameters of both modifications increase with increasing vacancy content, revealing the cause of different lattice constants that were previously reported for $α$-$Si_3N_4$.
