Effect of hydrogen-induced surface steps on the nanomechanical behavior of a CoCrFeMnNi high-entropy alloy revealed by in-situ electrochemical nanoindentation. (November 2019)

• Record Type: Journal Article
• Authors: Wang, Dong; Lu, Xu; Deng, Yun; Wan, Di; Li, Zhiming; Barnoush, Afrooz
• Is Part Of: Intermetallics. Volume 114(2019:Nov.)
• Publication Date: 2019-11
• Subjects: In-situ electrochemical nanoindentation -- High-entropy alloy -- Hydrogen embrittlement -- Hydrogen-induced surface steps -- Electron channeling contrast imaging -- Nanomechanics; Intermetallic compounds -- Metallography -- Periodicals; Metallic glasses -- Periodicals; Composés intermétalliques -- Métallographie -- Périodiques; 669.94
• DOI: 10.1016/j.intermet.2019.106605
• Languages: English
• ISSNs: 0966-9795

Abstract

Abstract: The effect of hydrogen on the nanomechanical properties of CoCrFeMnNi high-entropy alloy was investigated by in-situ electrochemical nanoindentation testing. The changes in surface morphology, elastic modulus, pop-in load, and hardness during hydrogen ingress and egress processes were systematically evaluated. The results show that hydrogen charging leads to the formation of irreversible slip lines accumulated as surface steps. Furthermore, the irreversible reduced pop-in load and elastic modulus, and reversible increased hardness are detected. In this paper, the mechanisms of hydrogen-induced surface steps together with their further influences on the nanomechanical properties are discussed in detail. Graphical abstract: Image 1 Highlights: In-situ nanoindentation test was used to investigate the H effect on CoCrFeMnNi HEA. Irreversible slip lines accumulated as surface steps were found during H charging. Surface steps resulted in irreversible reduced pop-in load and elastic modulus. Surface steps showed a minor influence on hardness with a reversible value. The mechanisms of H effect on each nanomechanical properties were discussed in detail.