Shear-induced anisotropic plastic flow from body-centred-cubic tantalum before melting.
Shear-induced anisotropic plastic flow from body-centred-cubic tantalum before melting.
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DOI：
10.1038/nmat2375
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发表时间：
2009-01
期刊：
影响因子：
41.2
通讯作者：
Christine J Wu;P. Söderlind;J. Glosli;J. Klepeis
中科院分区：
文献类型：
--
作者：
Christine J Wu;P. Söderlind;J. Glosli;J. Klepeis
在液体和塑性流动之间存在许多结构和光学相似性。因此，在高压和高温下区分它们是不平凡的，详细描述这些现象之间的转变对于我们理解高压下金属的熔化至关重要。在这里，我们报告了剪切诱导，部分无序粘性塑性流动从体心立方钽在加热下熔化成液体之前。这种热激活的结构转变产生了一种独特的一维结构，类似于具有宾汉塑料流变特性的液晶。这种机制并不是Ta所特有的，预计对其他金属更普遍。值得注意的是，这种转变与先前报道的异常低温熔化曲线完全一致，从而为长期存在的关于高压下金属熔化的争议提供了一个合理的解决方案。
There are many structural and optical similarities between a liquid and a plastic flow. Thus, it is non-trivial to distinguish between them at high pressures and temperatures, and a detailed description of the transformation between these phenomena is crucial to our understanding of the melting of metals at high pressures. Here we report a shear-induced, partially disordered viscous plastic flow from body-centred-cubic tantalum under heating before it melts into a liquid. This thermally activated structural transformation produces a unique, one-dimensional structure analogous to a liquid crystal with the rheological characteristics of Bingham plastics. This mechanism is not specific to Ta and is expected to hold more generally for other metals. Remarkably, this transition is fully consistent with the previously reported anomalously low-temperature melting curve and thus offers a plausible resolution to a long-standing controversy about melting of metals under high pressures.