Lee, Dong-Hyun Lee, Jung-A Zhao, Yakai Lu, Zhaoping Suh, Jin-Yoo Kim, Ju-Young Ramamurty, Upadrasta Kawasaki, Megumi Langdon, Terence G. Jang, Jae-il 2024-01-20T00:04:16Z 2024-01-20T00:04:16Z 2021-09-03 2017-11 1359-6454 https://pubs.kist.re.kr/handle/201004/122115 The influence of annealing on the constitutive stress-strain response of nanocrystalline (nc) CoCrFeMnNi high-entropy alloy (HEA) was investigated through a series of nanoindentation experiments using five different three-sided pyramidal indenters. The nc HEA, produced by high-pressure torsion (HPT), was subjected to annealing at 450 degrees C for 1 and 10 h. Microstructural analysis using transmission electron microscopy (TEM) showed that three different nano-scale precipitates (NiMn-, FeCo-, and Co-rich phases) form in the primary single-phase matrix of nc HEA after annealing. The strain-dependent plastic flow response of nc HEA pre- and post-annealing was estimated using the indentation strain and constraint factor, revealing a significant strain softening in nc HEA, which becomes pronounced after annealing. TEM analysis of the deformed material underneath the indenter suggests that the plastic deformation aids in the dissolution of the annealing-induced intermetallic precipitates, which could be the mechanism for the pronounced softening. The dissolution mechanism was rationalized by the destabilization of precipitates during plastic deformation due to the increase in interface energy. (C) 2017 Acta Materialia Inc. Published by Elsevier Ltd. All rights reserved. English PERGAMON-ELSEVIER SCIENCE LTD HIGH-PRESSURE TORSION MECHANICAL-PROPERTIES INCIPIENT PLASTICITY PEARLITIC STEEL INDENTER ANGLE HIGH DUCTILITY SOLID-SOLUTION STRAIN-RATE NANOINDENTATION BEHAVIOR Annealing effect on plastic flow in nanocrystalline CoCrFeMnNi high-entropy alloy: A nanomechanical analysis Article 10.1016/j.actamat.2017.08.057 1 ACTA MATERIALIA, v.140, pp.443 - 451 ACTA MATERIALIA 140 443 451 scie scopus 000413879800045 2-s2.0-85029008915 Materials Science, Multidisciplinary Metallurgy & Metallurgical Engineering Materials Science Metallurgy & Metallurgical Engineering Article HIGH-PRESSURE TORSION MECHANICAL-PROPERTIES INCIPIENT PLASTICITY PEARLITIC STEEL INDENTER ANGLE HIGH DUCTILITY SOLID-SOLUTION STRAIN-RATE NANOINDENTATION BEHAVIOR High-entropy alloy Nanocrystalline metal Annealing effect Constitutive behavior