Influences of hydrogen charging method on the hydrogen distribution and nanomechanical properties of face-centered cubic high-entropy alloy: A comparative study

Abstract

The influence of charging method on hydrogen (H) distribution and the resultant nanomechanical behavior of CoCrFeMnNi high-entropy alloy was examined and compared with another face-centered cubic structured alloy, an austenitic stainless steel. Through thermal desorption spectroscopy measurement and theoretical analysis, it was revealed that electrochemical (E-) charging induces steep gradient of H concentration near the surface while H was homogenously distributed after gaseous (G-) charging. Nanoindentation results show significant hardening in E-charged alloys while the hardness of G-charged alloys remains invariant. These differences were rationalized in terms of the nature of H distributions induced by different charging methods. (C) 2019 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved.