Nano-twinning in a γ′ precipitate strengthened Ni-based superalloy

作者：Shengyun Yuan, Zhihao Jiang, Junwei LIU, Yizhe Tang, Yong Zhang · 发表于：Materials Research Letters · 年份：2018 · DOI：10.1080/21663831.2018.1538021 · 被引用次数：41 · 研究领域：High Temperature Alloys and Creep、Microstructure and mechanical properties、Intermetallics and Advanced Alloy Properties

Twinning has been found to be a dominate mechanism in the γ′ precipitate strengthened Ni-based superalloys during service at intermediate temperatures. Here, high-resolution transmission electron microscopy and atomistic simulations have been combined to show that the twin nucleation process can be facilitated by Co replacing a fraction of Al in the γ′ precipitates, due to the negative binding energy of Co–Co atoms. The study further reveals that the presence of Co promotes a new twinning pathway featured with nucleation of one complex stacking fault (CSF) on the middle plane in between two separated CSFs.