TY - JOUR
T1 - Effect of ultrafine grain refinement on hydrogen embrittlement of metastable austenitic stainless steel
AU - Mine, Yoji
AU - Horita, Nobuaki
AU - Horita, Zenji
AU - Takashima, Kazuki
N1 - Funding Information:
The authors are indebted to Dr. M. Tsushida and Dr. T. Yamamuro, Kumamoto University for their assistance in the TEM studies. This work was supported in part by a Grant-in-Aid for Challenging Exploratory Research 16K14423 from the Japan Society for the Promotion of Science (JSPS). YM gratefully acknowledges the support of the ‘Program for Advancing Strategic International Networks to Accelerate the Circulation of Talented Researchers’ R2608. This study used facilities for severe plastic deformation in the International Research Centre on Giant Straining for Advanced Materials (IRC-GSAM) at Kyushu University, and FE-SEM with EBSD analyser in the Centre of Advanced Instrumental Analysis at Kyushu University.
Publisher Copyright:
© 2017 Hydrogen Energy Publications LLC
PY - 2017/6/1
Y1 - 2017/6/1
N2 - Micro-tensile tests were performed on high-pressure-torsion-processed specimens of type 304 steel with grain sizes in the range of 0.1–0.5 μm to clarify the effect of ultrafine grain refinement on the hydrogen embrittlement (HE) of metastable austenitic steel. The ultrafine-grained (UFG) specimens with average grain sizes < ∼0.4 μm exhibited a limited uniform elongation followed by a steady-stress regime in the stress–strain curves, which was attributed to a martensitic transformation. A high yield stress and a moderate elongation to failure were attained for the UFG specimens with an average grain size of ∼0.5 μm in the uncharged state. Hall–Petch relationships well hold between the yield stress and the average grain size for each uncharged and hydrogen-charged specimen. Hydrogen charging increased the friction stress by 40% but did not change the Hall–Petch coefficient. Hydrogen-induced ductility loss was mitigated by ultrafine grain refinement. Ductility loss due to hydrogen charging manifested in the local deformation after a martensitic transformation. This indicates that hydrogen does not significantly affect the martensitic transformation, but shortens the subsequent local deformation process.
AB - Micro-tensile tests were performed on high-pressure-torsion-processed specimens of type 304 steel with grain sizes in the range of 0.1–0.5 μm to clarify the effect of ultrafine grain refinement on the hydrogen embrittlement (HE) of metastable austenitic steel. The ultrafine-grained (UFG) specimens with average grain sizes < ∼0.4 μm exhibited a limited uniform elongation followed by a steady-stress regime in the stress–strain curves, which was attributed to a martensitic transformation. A high yield stress and a moderate elongation to failure were attained for the UFG specimens with an average grain size of ∼0.5 μm in the uncharged state. Hall–Petch relationships well hold between the yield stress and the average grain size for each uncharged and hydrogen-charged specimen. Hydrogen charging increased the friction stress by 40% but did not change the Hall–Petch coefficient. Hydrogen-induced ductility loss was mitigated by ultrafine grain refinement. Ductility loss due to hydrogen charging manifested in the local deformation after a martensitic transformation. This indicates that hydrogen does not significantly affect the martensitic transformation, but shortens the subsequent local deformation process.
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U2 - 10.1016/j.ijhydene.2017.04.249
DO - 10.1016/j.ijhydene.2017.04.249
M3 - Article
AN - SCOPUS:85019482356
SN - 0360-3199
VL - 42
SP - 15415
EP - 15425
JO - International Journal of Hydrogen Energy
JF - International Journal of Hydrogen Energy
IS - 22
ER -
