Abstract Molecular dynamics simulation is used to study vacancy cluster formation in β- and α-Si3N4 with varying vacancy contents (0–25.6 at%). Vacancies are randomly created in supercells, which were subsequently heat-treated for 114 ns. 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-Si3N4. 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-Si3N4 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-Si3N4.

中文翻译：

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β-和α-Si3N4中空位簇形成的分子动力学模拟

摘要 分子动力学模拟用于研究具有不同空位含量 (0–25.6 at%) 的 β- 和 α-Si3N4 中空位簇的形成。超胞中随机产生空位，随后对其进行 114 ns 的热处理。结果表明 β 和 α 都可以容忍高达 12.8 at% 的空位并形成簇，证实了之前的实验数据表明 α-Si3N4 中有 8 at% 的空位。然而，β 中 25.6 at% 的空位导致完全非晶化，而相同数量的 α 导致半非晶α 相转变为有缺陷的 β 相，导致新形成的 β 中的簇被去除。这清楚地解释了为什么在 β 中没有通过实验观察到簇空位，考虑到 β-Si3N4 陶瓷是由 α 产生的。此外，