Unstable twin in body-centered cubic tungsten nanocrystals
Unstable twin in body-centered cubic tungsten nanocrystals
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DOI：
10.1038/s41467-020-16349-8
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发表时间：
2020-05
影响因子：
16.6
通讯作者：
Xiang Wang;Jiangwei Wang;Yang He;Chongmin Wang;L. Zhong;S. Mao
中科院分区：
文献类型：
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作者：
Xiang Wang;Jiangwei Wang;Yang He;Chongmin Wang;L. Zhong;S. Mao
孪晶通常在低堆垛层错面心立方 (Fcc) 金属的塑性变形中被激活，但在室温和慢应变速率下的体心立方 (Bcc) 金属中很少发现。在这里，通过在原子尺度上进行原位透射电子显微镜（TEM），我们发现，与大多数 Fcc 金属形成鲜明对比的是，Bcc 金属中的大多数形变孪晶是不稳定的，并且在卸载时会自发地发生解孪晶。人们发现Bcc孪晶的这种意想不到的不稳定性与倾斜孪晶边界的普遍存在密切相关，倾斜孪晶边界是一种特殊结构，孪晶边界不平行于孪晶面，不稳定程度与倾斜孪晶边界的比例成正比。这项工作为 Bcc 金属中变形孪晶的结构和稳定性提供了重要的见解。
Twinning is commonly activated in plastic deformation of low stacking-fault face-centered cubic (Fcc) metals but rarely found in body-centered cubic (Bcc) metals under room temperature and slow strain rates. Here, by conducting in situ transmission electron microscopy (TEM) at atomic scale, we discover that, in stark contrast to those in most Fcc metals, a majority of deformation twins in Bcc metals are unstable and undergo spontaneously detwinning upon unloading. Such unexpected instability of Bcc twins is found to be closely related to the prevalence of the inclined twin boundaries—a peculiar structure where twin boundaries are not parallel to the twinning plane, and the degree of instability is in direct proportion to the fraction of the inclined twin boundary. This work provides significant insights into the structure and stability of deformation twins in Bcc metals.