Design of Stable Nanocrystalline Alloys
Design of Stable Nanocrystalline Alloys
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DOI：
10.1126/science.1224737
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发表时间：
2012-08-24
期刊：
影响因子：
56.9
通讯作者：
Schuh, Christopher A.
中科院分区：
文献类型：
--
作者：
Chookajorn, Tongjai;Murdoch, Heather A.;Schuh, Christopher A.
纳米结构金属通常不稳定；即使在低温下，它们的颗粒也会快速生长，这使得它们难以加工并且通常不适合使用。人们发现合金化可以提高稳定性，但仅限于少数凭经验发现的系统。我们开发了一个理论框架，可以用来设计稳定的纳米结构合金。基于热力学模型的纳米结构稳定性图用于设计稳定的纳米结构钨合金。我们确定了一种候选合金 W-Ti，并证明其在高温、长时间条件下的稳定性显着增强，适合粉体纳米结构钨的生产。这种纳米结构合金采用了目前的理论框架所预期的非均质化学分布，但在传统的整体热力学的基础上却是出乎意料的。
Nanostructured metals are generally unstable; their grains grow rapidly even at low temperatures, rendering them difficult to process and often unsuitable for usage. Alloying has been found to improve stability, but only in a few empirically discovered systems. We have developed a theoretical framework with which stable nanostructured alloys can be designed. A nanostructure stability map based on a thermodynamic model is applied to design stable nanostructured tungsten alloys. We identify a candidate alloy, W-Ti, and demonstrate substantially enhanced stability for the high-temperature, long-duration conditions amenable to powder-route production of bulk nanostructured tungsten. This nanostructured alloy adopts a heterogeneous chemical distribution that is anticipated by the present theoretical framework but unexpected on the basis of conventional bulk thermodynamics.