Vitrification of a monatomic metallic liquid
Vitrification of a monatomic metallic liquid
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DOI：
10.1038/nature06044
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发表时间：
2007-08-16
期刊：
影响因子：
64.8
通讯作者：
Angell, C. A.
中科院分区：
文献类型：
--
作者：
Bhat, M. H.;Molinero, V.;Angell, C. A.
虽然大多数技术中使用的玻璃是氧化物或硫属化物的复杂混合物，但也有许多纯物质的例子-“玻璃形成剂”-在冷却过程中也无法结晶。大多数玻璃形成剂是有机分子系统，但也有重要的无机例子（1，2），如二氧化硅和元素硒（后者是聚合物）。块体金属玻璃现在可以制成（3）;但是，除了Zr 50 Cu 50（参考文献4），它们需要多个组分以避免在正常液体冷却期间结晶。双组分“金属玻璃”通常可以通过超淬灭来实现，但这迄今为止还没有用单组分体系来实现。当晶体成核速率缓慢时，玻璃形成，尽管产生缓慢成核条件的因素还没有很好地理解。在这里，我们应用最近的分子动力学模拟研究（5）中获得的见解，为金属液体锗的成功玻璃化创造条件。我们的研究结果还提供了一个罕见的多晶过渡之前的金刚石立方相结晶的显微证据。
Although the majority of glasses in use in technology are complex mixtures of oxides or chalcogenides, there are numerous examples of pure substances - 'glassformers' - that also fail to crystallize during cooling. Most glassformers are organic molecular systems, but there are important inorganic examples too(1,2), such as silicon dioxide and elemental selenium ( the latter being polymeric). Bulk metallic glasses can now be made(3); but, with the exception of Zr50Cu50 ( ref. 4), they require multiple components to avoid crystallization during normal liquid cooling. Two-component 'metglasses' can often be achieved by hyperquenching, but this has not hitherto been achieved with a single- component system. Glasses form when crystal nucleation rates are slow, although the factors that create the slow nucleation conditions are not well understood. Here we apply the insights gained in a recent molecular dynamics simulation study(5) to create conditions for successful vitrification of metallic liquid germanium. Our results also provide micrographic evidence for a rare polyamorphic transition preceding crystallization of the diamond cubic phase.