TY - JOUR
T1 - Grain-boundary diffusion and precipitate trapping of hydrogen in ultrafine-grained austenitic stainless steels processed by high-pressure torsion
AU - Mine, Yoji
AU - Tachibana, Kazutaka
AU - Horita, Zenji
N1 - Funding Information:
The authors would like to thank Professor V.N. Shivanyuk of Kyushu University for the helpful discussion and valuable comments on the interaction between hydrogen and precipitates. This research was supported in part by a Grant-in-Aid for Scientific Research from the Ministry of Education, Culture, Sports, Science and Technology of Japan in the Innovative Area “Bulk Nanostructured Metals”, and in part by the NEDO , Fundamental Research Project on Advanced Hydrogen Science (2006–2012). A part of this research was carried out within the frame of Kyushu University Interdisciplinary Programs in Education and Projects in Research Development (P&P).
PY - 2011/10/25
Y1 - 2011/10/25
N2 - This study was conducted to clarify the effects of grain boundaries and precipitates on room-temperature hydrogen transport in two types of austenitic stainless steels with ultrafine-grained structures produced by high-pressure torsion (HPT) and subsequent annealing. The grains in the Fe-25Ni-15Cr (in mass%) alloy containing Ti and the Fe-25Cr-20Ni alloy were refined by the HPT-processing to ∼150 and ∼85nm, respectively. The high-temperature annealing after the HPT processing led to the precipitation of η-Ni3Ti for the former and σ-FeCr for the latter. In the HPT-processed specimens, hydrogen diffusivity was enhanced through short-circuit diffusion because of the increased population of grain boundaries in comparison with the increased opportunity of hydrogen trapping on dislocations. As for the post-HPT-annealed specimens having the precipitates, the hydrogen diffusion was hindered by the hydrogen trapping on η-Ni3Ti precipitates, but was not affected by σ-FeCr precipitation. This depends on the affinity between hydrogen and constituting elements.
AB - This study was conducted to clarify the effects of grain boundaries and precipitates on room-temperature hydrogen transport in two types of austenitic stainless steels with ultrafine-grained structures produced by high-pressure torsion (HPT) and subsequent annealing. The grains in the Fe-25Ni-15Cr (in mass%) alloy containing Ti and the Fe-25Cr-20Ni alloy were refined by the HPT-processing to ∼150 and ∼85nm, respectively. The high-temperature annealing after the HPT processing led to the precipitation of η-Ni3Ti for the former and σ-FeCr for the latter. In the HPT-processed specimens, hydrogen diffusivity was enhanced through short-circuit diffusion because of the increased population of grain boundaries in comparison with the increased opportunity of hydrogen trapping on dislocations. As for the post-HPT-annealed specimens having the precipitates, the hydrogen diffusion was hindered by the hydrogen trapping on η-Ni3Ti precipitates, but was not affected by σ-FeCr precipitation. This depends on the affinity between hydrogen and constituting elements.
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U2 - 10.1016/j.msea.2011.07.031
DO - 10.1016/j.msea.2011.07.031
M3 - Article
AN - SCOPUS:80052360970
SN - 0921-5093
VL - 528
SP - 8100
EP - 8105
JO - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
JF - Materials Science & Engineering A: Structural Materials: Properties, Microstructure and Processing
IS - 28
ER -