一种用于纳米晶薄膜中更真实晶界的圆柱烧结方法
A cylindrical sintering method for more realistic grain boundaries in nanocrystalline thin films
- Institute of Physics of Materials, The Czech Academy of Sciences（材料物理研究所，捷克科学院）
- Central European Institute of Technology, Brno University of Technology（中欧技术研究所，布尔诺理工大学）
- Charles University, Faculty of Mathematics and Physics（查理大学，数学与物理学院）
机构由 AI 辅助整理，请以论文原文为准。
AI总结：
本文提出圆柱烧结方法生成具有更宽无序晶界的纳米晶铝薄膜样品，相比Voronoi方法更真实，且力学性能更低，并发现几何与势函数影响独立可加，存在反Hall-Petch关系。
AI中文摘要：
在纳米晶金属的分子动力学模拟中，模拟与实验力学性能之间的差异通常源于样品构建方法和原子间势函数的选择。我们提出了一种圆柱烧结方法，用于生成具有比常用Voronoi镶嵌方法更宽、更无序晶界的纳米晶铝薄膜样品，同时保持对晶粒尺寸、形状和取向的确定性控制。在相同条件下，使用经典的Pascuet15 MEAM势和tabGAP机器学习势，将圆柱烧结样品与六边形Voronoi参考样品进行基准测试。圆柱烧结样品始终表现出比六边形Voronoi样品更低的力学性能，这是由于其更宽、更无序的晶界——这一效应与势函数的选择无关。值得注意的是，改变样品几何形状和改变原子间势函数对预测性能产生的影响相当、可叠加且相互独立，这凸显了未来的分子动力学研究必须同时固定这两个变量才能进行有意义的比较。共同近邻分析和位错提取分析证实，变形主要由晶界介导的塑性主导。单轴拉伸测试揭示了两种样品类型和两种势函数下均存在反Hall-Petch关系，随着晶粒尺寸从40.34 nm减小到4.84 nm，力学性能单调下降。圆柱烧结方法提供了一种物理上真实、几何可控的替代方案，弥合了理想化Voronoi模型与无序实验晶界结构之间的差距。
英文摘要：
Discrepancies between simulated and experimental mechanical properties in molecular dynamics simulations of nanocrystalline metals typically arise from the sample-construction method and the interatomic potential choice. We introduce a cylindrical sintering method to generate nanocrystalline aluminum thin-film samples with wider, more disordered grain boundaries than the usual Voronoi tessellation method, while maintaining deterministic control over grain size, shape, and orientation. Cylindrical sintered samples are benchmarked against hexagonal Voronoi references under identical conditions using both the classical Pascuet15 MEAM and tabGAP machine-learning potentials. Cylindrical sintered samples consistently show lower mechanical properties than hexagonal Voronoi samples due to their wider, more disordered grain boundaries - an effect independent of the choice of potential. Notably, changing the sample geometry and changing the interatomic potential produce comparable, additive, and independent shifts in predicted properties, highlighting that future molecular dynamics studies must hold both variables fixed for meaningful comparisons. Common neighbor and dislocation extraction analyses confirm that deformation is dominated by grain-boundary-mediated plasticity. Uniaxial tensile tests reveal an inverse Hall-Petch relationship for both sample types and both potentials, with mechanical properties decreasing monotonically as grain size reduces from 40.34 to 4.84 nm. The cylindrical sintering method offers a physically realistic, geometrically controlled alternative that bridges idealized Voronoi models and disordered experimental grain-boundary structures.
