Direct observation of dislocation dissociation and Suzuki segregation in a Mg–Zn–Y alloy by aberration-corrected scanning transmission electron microscopy
Direct observation of dislocation dissociation and Suzuki segregation in a Mg–Zn–Y alloy by aberration-corrected scanning transmission electron microscopy
复制标题
DOI：
10.1016/j.actamat.2012.09.067
复制
发表时间：
2013
期刊：
影响因子：
9.4
通讯作者：
Zhiqing Yang;M. Chisholm;G. Duscher;Xiuliang Ma;S. Pennycook
中科院分区：
文献类型：
--
作者：
Zhiqing Yang;M. Chisholm;G. Duscher;Xiuliang Ma;S. Pennycook
用像差校正扫描电子显微镜在原子尺度上研究了塑性变形的Mg-Zn-Y合金中的晶体缺陷，为了解该材料的变形行为和强化机制提供了重要的结构数据。对不同类型位错解离引起的形变层错的原子尺度结构进行了实验表征和模型模拟。在原子水平上，从实验上证实了在300℃塑性变形过程中，锌和Y沿位错解离形成的层错的Suzuki偏析。该合金的层错能为4.0mJm~10.3mJm−~2。新形成的纳米宽的层错及其在镁颗粒中的锌/Y偏析对该合金在高温下具有优异的强度起着重要作用。
Crystal defects in a plastically deformed Mg–Zn–Y alloy have been studied on the atomic scale using aberration-corrected scanning transmission electron microscopy, providing important structural data for understanding the material’s deformation behavior and strengthening mechanisms. Atomic scale structures of deformation stacking faults resulting from dissociation of different types of dislocations have been characterized experimentally, and modeled. Suzuki segregation of Zn and Y along stacking faults formed through dislocation dissociation during plastic deformation at 300°C is confirmed experimentally on the atomic level. The stacking fault energy of the Mg–Zn–Y alloy is evaluated to be in the range of 4.0–10.3mJm−2. The newly formed nanometer-wide stacking faults with their Zn/Y segregation in Mg grains play an important role in the superior strength of this alloy at elevated temperatures.