In situ transmission electron microscopy studies of the solid-liquid interface
In situ transmission electron microscopy studies of the solid-liquid interface
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DOI：
10.1557/mrs2004.266
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发表时间：
2004-12-01
期刊：
影响因子：
5
通讯作者：
Saka, H
中科院分区：
文献类型：
--
作者：
Howe, JM;Saka, H
原位电子显微镜研究使人们能够以亚纳米空间分辨率确定固-液(S-L)界面的结构、化学和动力学行为。本文阐述了原位电子显微镜对理解Al-Si合金中的S-L界面以及Al和Fe中的液态粒子的一些重要贡献。讨论了S-L界面上液体的有序性、界面成分的变化、界面迁移的动力学和机理、小颗粒的接触角和平衡熔化温度等四个主要方面。研究结果表明：(1)在Al-Si合金中，(1)S-L界面处形成了偏序层；(2)在S-L界面上，晶体和成分的变化同时发生；(3)在极低的过冷度下，A界面是弥散的，其生长速度可达几nm/S；(4)直径小于10 nm的In粒子在A或Fe中的熔化温度可提高或降低，这取决于S-L界面在三相结处形成的接触角。这些结果说明了原位透射电子显微镜的优点，它为控制材料中S-L界面行为的机制提供了基本的见解。
In situ transmission electron microscopy (TEM) studies allow one to determine the structure, chemistry, and kinetic behavior of solid-liquid (S-L) interfaces with subnanometer spatial resolution. This article illustrates some important contributions of in situ TEM to our understanding of S-L interfaces in Al-Si alloys and liquid In particles in Al and Fe matrices. Four main areas are discussed: ordering in the liquid at a S-L interface, compositional changes across the interface, the kinetics and mechanisms of interface migration, and the contact angles and equilibrium melting temperature of small particles. Results from these studies reveal that (1) partially ordered layers form in the liquid at a Si{111} S-L interface in an Al-Si alloy, (2) the crystalline and compositional changes occur simultaneously across an Al S-L interface, (3) the A interface is diffuse and its growth can be followed at velocities of a few nm/s at extremely low undercoolings, and (4) the melting temperature of In particles less than similar to 10 nm in diameter can be raised or lowered in A or Fe, depending on the contact angle that the S-L interface makes at the three-phase junction. These results illustrate the benefits of in situ TEM for providing fundamental insight into the mechanisms that control the behavior of S-L interfaces in materials.