论文标题
硅酸盐玻璃的断裂：原子级特性之间的微腔和相关性
Fracture of silicate glasses: Micro-cavities and correlations between atomic-level properties
论文作者
论文摘要
我们使用大型模拟研究单轴张力下的二氧化硅和硅酸盐玻璃的动态断裂。应力 - 应变曲线表明二氧化硅玻璃是脆性的，而富含NA的玻璃显示出明显的延展性。在裂纹速度中也可以看到强大的依赖性，该裂纹速度的含量为1800 m/s，对于低Na浓度的玻璃，如果浓度较高，则降低至700 m/s。我们发现，在富含Na的玻璃的断裂过程中，非常不规则的腔体在裂纹前方的前方较大至3-4 nm，表明这些玻璃杯中存在纳米可靠性。在发生断裂之前，局部组成，结构和机械性能在空间中是异质的，并且对所施加的应变显示了很强的依赖性。对这些局部特性之间的相关性的进一步分析，可以获得对玻璃的变形和断裂的更好理解，以及如何靠近裂纹尖端的局部加热（最高几百度）可以使结构放松。
We use large-scale simulations to investigate the dynamic fracture of silica and sodium-silicate glasses under uniaxial tension. The stress-strain curves demonstrate that silica glass is brittle whereas the glasses rich in Na show pronounced ductility. A strong composition dependence is also seen in the crack velocity which is on the order of 1800 m/s for glasses with low Na concentration and decreases to 700 m/s if the concentration is high. We find that during the fracture of Na-rich glasses very irregular cavities as large as 3-4 nm form ahead of the crack front, indicating the presence of nanoductility in these glasses. Before fracture occurs, the local composition, structure, and mechanical properties are heterogeneous in space and show a strong dependence on the applied strain. Further analysis of the correlations between these local properties allows to obtain a better microscopic understanding of the deformation and fracture of glasses and how the local heating close to the crack tip, up to several hundred degrees, permits the structure to relax.
