TY - JOUR
T1 - Quantitative Evaluation of Hydrogen Effects on Evolutions of Deformation-Induced ε-Martensite and Damage in a High-Mn Steel
AU - Hao, Chunxi
AU - Koyama, Motomichi
AU - Akiyama, Eiji
N1 - Funding Information:
This work was financially supported by JSPS KAKENHI (JP16H06365 and JP20H02457).
Publisher Copyright:
© 2020, The Minerals, Metals & Materials Society and ASM International.
PY - 2020/12
Y1 - 2020/12
N2 - We investigated the effects of hydrogen on ε-martensite-related damage evolution (crack/void initiation and growth) in Fe-Mn-Si-base austenitic steel using tensile tests after gaseous hydrogen charging at 100 MPa. Specifically, we evaluated the quantitative hydrogen effects on ε-martensite fraction and associated damage evolution with different strains and strain rates. Hydrogen charging increased the probability of ε-martensite-related damage initiation and deteriorated micro-damage arrestability, which decreased elongation. The primary factor causing the detrimental hydrogen effects on resistance to damage evolution was the promotion of deformation-induced γ-ε martensitic transformation. An increasing strain rate from 10−4 to 10−2 s−1 suppressed the γ-ε martensitic transformation and correspondingly increased elongation. Interestingly, the ε-martensite fraction near the fracture surface did not change with increasing strain rate, but the area fraction of the brittle-like fracture region decreased. This fact implied that the brittle-like fracture at the low strain rate, which had a longer time for damage growth, was assisted by stress-driven hydrogen diffusion near the crack/void tips.
AB - We investigated the effects of hydrogen on ε-martensite-related damage evolution (crack/void initiation and growth) in Fe-Mn-Si-base austenitic steel using tensile tests after gaseous hydrogen charging at 100 MPa. Specifically, we evaluated the quantitative hydrogen effects on ε-martensite fraction and associated damage evolution with different strains and strain rates. Hydrogen charging increased the probability of ε-martensite-related damage initiation and deteriorated micro-damage arrestability, which decreased elongation. The primary factor causing the detrimental hydrogen effects on resistance to damage evolution was the promotion of deformation-induced γ-ε martensitic transformation. An increasing strain rate from 10−4 to 10−2 s−1 suppressed the γ-ε martensitic transformation and correspondingly increased elongation. Interestingly, the ε-martensite fraction near the fracture surface did not change with increasing strain rate, but the area fraction of the brittle-like fracture region decreased. This fact implied that the brittle-like fracture at the low strain rate, which had a longer time for damage growth, was assisted by stress-driven hydrogen diffusion near the crack/void tips.
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U2 - 10.1007/s11661-020-06021-7
DO - 10.1007/s11661-020-06021-7
M3 - Article
AN - SCOPUS:85092187914
SN - 1073-5623
VL - 51
SP - 6184
EP - 6194
JO - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
JF - Metallurgical and Materials Transactions A: Physical Metallurgy and Materials Science
IS - 12
ER -