Two-dimensional grain boundary sliding and mantle dislocation accommodation in ODS ferritic steel
Two-dimensional grain boundary sliding and mantle dislocation accommodation in ODS ferritic steel
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DOI：
10.1016/j.actamat.2016.08.034
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发表时间：
2016-11-01
期刊：
影响因子：
9.4
通讯作者：
Ukai, Shigeharu
中科院分区：
文献类型：
--
作者：
Masuda, Hiroshi;Tobe, Hirobumi;Ukai, Shigeharu
为了了解超塑性，研究了位错和微观组织演化对晶界滑移(GBS)的影响机制。利用聚焦离子束绘制的表面标记分析了氧化物弥散强化铁素体钢高温剪切过程中出现的二维GBS，该钢具有细长的取向的晶格结构。此外，还用电子背散射衍射和电子沟道衬度成像评价了晶体中的容位错结构。在变形初期，GBS在晶界附近的“地幔”区域引发位错滑移。这些地衣往往出现在抗GBS的区域周围，如弯曲的边界和谷粒突起。其次，地幔位错在核/地幔边界通过动态回复形成位错墙，然后沿{110}晶面形成小角度边界(LAB)。最后，在新形成的实验室中发生了二次GBS或刚性旋转，以补偿最初的GBS，并导致连续的动态再结晶。这些地幔位错活动和亚结构演化机制被图形模拟，并与前人的研究进行了比较。(C)2016 Acta Materialia Inc.由爱思唯尔有限公司出版。版权所有。
The mechanism governing grain boundary sliding (GBS) accommodated by dislocation and micro structural evolution in regions and III was studied to understand superplasticity. Two-dimensional GBS that occurred during high-temperature shear in oxide dispersion strengthened ferritic steel exhibiting an elongated and aligned grain structure was analyzed using surface markers drawn by focused ion beams. In addition, the accommodating dislocation structure was evaluated by electron back scattered diffraction and electron channeling contrast imaging. In the initial stage of deformation, GBS triggered dislocation slippage in "mantle" areas near grain boundaries. These mantles tended to appear around GBS-resistant areas such as curved boundaries and grain protrusions. Next, the mantle dislocations generated dislocation walls before forming low-angle boundaries (LABs) along {110} crystallographic planes via dynamic recovery at the core/mantle boundaries. Finally, secondary GBS or rigid rotation occurred at the newly formed LABs to compensate for the initial GBS and resulted in continuous dynamic recrystallization. These mantle dislocation activities and substructural evolution mechanisms were graphically modeled and validated by comparison with previous studies. (C) 2016 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.