论文标题

原位TEM实验的数据挖掘:关于cocrfemnni合金脱位的动力学

Data-mining of In-Situ TEM Experiments: on the Dynamics of Dislocations in CoCrFeMnNi Alloys

论文作者

Zhang, Chen, Song, Hengxu, Oliveros, Daniela, Fraczkiewicz, Anna, Legros, Marc, Sandfeld, Stefan

论文摘要

与``经典''合金相比,高熵合金是一类材料,在机械性能方面具有许多重大改进。相应的结构特性关系尚不完全清楚,但是通常认为良好的机械性能与由于合金化而形成的复杂能量景观的脱位相互作用密切相关。尽管原位透射电子显微镜(TEM)允许对移动位错的结构和动力学进行高分辨率研究,并使局部障碍物/能量``景观''直接可见。然而,这种观察仅仅是定性的,并且对位错之间的相互作用与能量格局之间的相互作用进行了详细的三维分析。在这项工作中,我们将脱位用作``探针''的``探针'',这对局部能量最大值,在脱位运动中起着固定点的作用。为此,我们开发了一种独特的数据挖掘方法,该方法可以执行粗粒的时空分析,从而使合奏平均相当数量的快照。我们研究了固定点对cocrfemnni合金的脱位滑行行为的影响,并发现(i)(i)当脱位滑动时,固定点强度会变化,并且(ii)(ii)固定点沿着靠近Burgers矢量方向的方向移动。我们的数据挖掘方法一般可以应用于脱位运动,使其成为脱位研究的有用工具。

High entropy alloys are a class of materials with many significant improvements in terms of mechanical properties as compared to ``classical'' alloys. The corresponding structure-property relations are not yet entirely clear, but it is commonly believed that the good mechanical performance is strongly related to dislocation interactions with the complex energy landscape formed due to alloying. Although in-situ Transmission Electron Microscopy (TEM) allows high-resolution studies of the structure and dynamics of moving dislocations and makes the local obstacle/energy ``landscape'' directly visible in the geometry of dislocations; such observation, however, are merely qualitative, and detailed three-dimensional analyses of the interaction between dislocations and the energy landscape is still missing. In this work, we utilized dislocations as ``probes'' for the local energy maxima which play the role of pinning points for the dislocation movement. To this end, we developed a unique data-mining approach that can perform coarse-grained spatio-temporal analysis, making ensemble averaging of a considerable number of snapshots possible. We investigate the effect of pinning points on the dislocation gliding behavior of CoCrFeMnNi alloy during in-situ TEM straining and find that (i) the pinning point strength changes when dislocations glide through and (ii) the pinning point moves along the direction close to the Burgers vector direction. Our data-mining method can be applied to dislocation motion in general, making it a useful tool for dislocation research.

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