Building up a weaker network: The effect of intermediate range glass structure on liquid fragility
Building up a weaker network: The effect of intermediate range glass structure on liquid fragility
复制标题
建立较弱的网络：中程玻璃结构对液体脆性的影响
DOI：
10.1016/j.jnoncrysol.2014.05.010
复制
发表时间：
2014
影响因子：
3.5
通讯作者：
S. Schnell
中科院分区：
文献类型：
--
作者：
D. Sidebottom;Tri D Tran;S. Schnell
对无定形网络稳定性的经典考虑已经明智地得出结论，当机械约束被去除时，网络应该减弱。在共价键合的玻璃网络中，这种弱化表现为“脆性”，并且在许多情况下，脆性随着共价键密度的降低而增加。然而，共价玻璃，拥有大量的中程秩序（IRO）表现出增加的脆弱性与键密度增加-一个矛盾的削弱，尽管增加了增强约束。在这里，我们解决这个悖论，建议这样的IRO包含网络需要重整化。粗粒化的IRO结构单元的建议，允许网络有效地削弱，尽管在整体密度的债券。通过这种粗粒化的方法，我们证明了网络连接的脆弱性的普遍依赖性的出现，以及遵守超过75个不同的网络形成的玻璃，包括硫属化物，硼酸盐，锗酸盐，磷酸盐和铝磷酸盐。
Classical considerations of the stability of amorphous networks have sensibly concluded that a network should weaken when mechanical constraints are removed. In covalently-bonded glass networks, this weakening is evidenced by the “fragility” and, in many cases, the fragility increases as the density of covalent bonds decreases. However, covalent glasses that possess substantial intermediate range order (IRO) exhibit an increase of fragility with increasing bond density — a paradoxical weakening in spite of the addition of reinforcing constraints. Here we resolve this paradox by suggesting that such IRO-containing networks require a renormalization. A coarse-graining of IRO structural units is proposed that permits a network to effectively weaken despite increases in the overall density of bonds. Through this coarse-graining approach, we demonstrate the emergence of a universal dependence of fragility on network connectivity that is well obeyed by more than 75 distinct network-forming glasses including chalcogenides, borates, germanates, phosphates and aluminophosphates.