このエントリーをはてなブックマークに追加
ID 58673
Author
Okayasu, Mitsuhiro Graduate School of Natural Science and Technology, Okayama University Kaken ID researchmap
Motojima, Jun Graduate School of Natural Science and Technology, Okayama University
Abstract
In this work, the hydrogen embrittlement (HE) characteristics of high-tensile steel sheets with different microstructural characteristics were investigated. The sheets were fabricated via cold rolling (CR), water quenching (WQ), baking hardening (BH), and low-temperature annealing (LT), and their HE characteristics were clarified by examining the relationships between the microstructural characteristics and the severity of HE. Severe HE occurred in the WQ sample with hydrogen trapping at the boundaries of the retained austenite phases, resulting in intergranular and cleavage-like brittle failure. A reduction in HE was realized after the BH and LT processes. In these cases, hydrogen trapping was divided between the ε-carbide in the lattice spacings and at the boundaries of retained austenite, resulting in a mixed ductile/brittle failure mode. The extent of HE in the CR sample was similar to those in the BH and LT samples. However, the trapping sites were different; hydrogen trapping in the CR sample occurred in the slip band and around dislocations, resulting in delamination-like brittle failure on the slip planes. The extent of HE was also affected by the strain rate. More severe HE occurred in both the WQ and BH samples loaded slowly at 0.01 mm min−1 compared to the samples loaded 1.0 mm min−1 (i.e., intergranular failure). In this case, HE was affected by the large amount of hydrogen atoms trapped at the boundaries of the retained austenite phases. The hydrogen atoms in the lattice structure and ε-carbide migrated to the boundaries via dislocation movement. The extent of deterioration in tensile strength was two times higher in the samples loaded at the higher speed of 1.0 mm min−1 compared to those loaded at 0.01 mm min−1. Finally, the hydrogen trapping and failure mechanisms on the nano and atomic scales were discussed based on the results of the microstructural analyses.
Keywords
High-tensile steel
Hydrogen embrittlement
Hydrogen trapping
Hydrogen diffusion
Carbide
Lattice structure
Note
This fulltext available in May 2022.
Published Date
2020-05-06
Publication Title
Materials Science and Engineering: A
Volume
volume790
Publisher
Elsevier
Start Page
139418
ISSN
09215093
NCID
AA10720420
Content Type
Journal Article
language
英語
OAI-PMH Set
岡山大学
Copyright Holders
© 2020 Elsevier B.V. All rights reserved.
File Version
author
DOI
Related Url
isVersionOf https://doi.org/10.1016/j.msea.2020.139418
License
https://creativecommons.org/licenses/by-nc-nd/4.0/