Nanostructured Oxide‐Dispersion‐Strengthened CoCrFeMnNi High‐Entropy Alloys with High Thermal Stability

• Published in: Advanced engineering materials Vol. 23; no. 9
• Main Authors: Zhang, Xiang, Wang, Fei, Yan, Xueliang, Li, Xing-Zhong, Hattar, Khalid, Cui, Bai
• Format: Journal Article
• Language: English
• Published: Germany Wiley Blackwell (John Wiley & Sons) 01.09.2021
• Subjects: high-entropy alloys; nanostructured alloys; oxide-dispersion-strengthened alloys; thermal stability
• ISSN: 1438-1656; 1527-2648
• DOI: 10.1002/adem.202100291

A nanostructured oxide‐dispersion‐strengthened (ODS) CoCrFeMnNi high‐entropy alloy (HEA) is synthesized by a powder metallurgy process. The thermal stability, including the grain size and crystal structure of the HEA matrix and oxide dispersions, is carefully investigated by X‐ray diffraction (XRD) and electron microscopy characterizations after annealing at 900 °C. The limited grain growth may be attributed to Zener pinning of yttria dispersions that impede the grain boundary mobility and diffusivity. The high hardness is caused by both the fine grain size and yttria dispersions, which are also retained after annealing at 900 °C. Herein, it is implied that the combination of ODS and HEA concepts may provide a new design strategy for the development of thermally stable nanostructured alloys for extreme environments. The combination of oxide‐dispersion‐strengthening (ODS) and high‐entropy alloy (HEA) concepts may lead to the development of thermally stable nanostructured alloys for extreme environments. The nanostructured ODS CoCrFeMnNi HEA maintains a high thermal stability at 900 °C with limited grain growth, which may be attributed to the yttria dispersions as pinning sites to impede the grain boundary mobility.