Geometry of Triple Junctions during Grain Boundary Premelting.
Geometry of Triple Junctions during Grain Boundary Premelting.
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晶界预熔过程中三重结的几何形状
DOI：
10.1103/physrevlett.127.225701
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发表时间：
2021
影响因子：
8.6
通讯作者：
M. Apel
中科院分区：
文献类型：
--
作者：
M. Torabi Rad;G. Boussinot;M. Apel
能量大于固液界面能量两倍的晶界（GB）表现出预熔化现象，在略低于本体熔化温度的温度下会形成原子薄的液体层。预熔会对多晶材料的结构完整性和机械高温性能产生严重影响，在凝固的最后阶段形成裂纹时也是如此。干燥 GB 和沿 GB 传播的液体层的两个固液界面之间的三重接界不能根据杨氏定律从宏观连续介质特性和表面张力平衡来定义。我们展示了如何使用分离势结合原子尺度物理来规范三联结的状态，并产生具有明确定义的微观接触角的平衡。我们通过使用多相场模型进行动力学模拟来支持这一发现，该多相场模型在纯动力学和扩散条件下具有潜在的障碍。一般来说，我们的结果应该提供对 GB 相变动力学的见解，其中与液态金属脆化相关的复杂现象就是一个例子。
Grain boundaries (GBs) whose energy is larger than twice the energy of the solid-liquid interface exhibit the premelting phenomenon, for which an atomically thin liquid layer develops at temperatures slightly below the bulk melting temperature. Premelting can have a severe impact on the structural integrity of a polycrystalline material and on the mechanical high-temperature properties, also in the context of crack formation during the very last stages of solidification. The triple junction between a dry GB and the two solid-liquid interfaces of a liquid layer propagating along the GB cannot be defined from macroscopic continuum properties and surface tension equilibria in terms of Young’s law. We show how incorporating atomistic scale physics using a disjoining potential regularizes the state of the triple junction and yields an equilibrium with a well-defined microscopic contact angle. We support this finding by dynamical simulations using a multiphase field model with obstacle potential for both purely kinetic and diffusive conditions. Generally, our results should provide insights on the dynamics of GB phase transitions, of which the complex phenomena associated with liquid metal embrittlement are an example.
影响因子：
3.3
作者：
Boettger, B.;Apel, M.;Zhou, B.
通讯作者：
Zhou, B.