TY - JOUR A1 - Glowacka, A. A1 - Wozniak, M. J. A1 - Nolze, Gert A1 - Swiatnicki, W. A. T1 - Hydrogen induced phase transformations in austenitic-ferritic steel JF - Solid State Phenomena N2 - The hydrogen influence on the microstructure of the austenitic-ferritic Cr22-Ni5-Mo3 stainless steel was investigated. Cathodic hydrogen charging was performed electrochemically from aqueous solution of 0.1M H2SO4 with hydrogen entry promoter addition. The aim of this study was to reveal microstructural changes appearing during the hydrogen charging and particularly to clarify the occurrence of phase transformations induced by hydrogen. The specific changes in both phases of steel were observed. In the ferritic phase, strong increase of dislocation density was noticed. Longer time of hydrogen charging leaded also to the strips and twin plates formation in ferrite phase. In the austenitic phase, the generation of stacking faults, followed by the formation of α' martensite was remarked. KW - Steel KW - Hydrogen KW - Embrittlement KW - Electron backscatter diffraction KW - SEM PY - 2006 DO - https://doi.org/10.4028/www.scientific.net/SSP.112.133 SN - 1662-9779 VL - 112 SP - 133 EP - 140 AN - OPUS4-38031 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Glowacka, A. A1 - Nolze, Gert A1 - Swiatnicki, W. A. T1 - EBSD study of corrosion fatigue of austenitic-ferritic steel JF - Archives of Metallurgy and Materials N2 - Fatigue crack propagation investigations have been performed in austenitic-ferritic duplex stainless steel H22N5M3 in air and during hydrogen charging, using various frequencies of loading. Strong differences of crack propagation velocity depending on the test conditions were noticed. Lower frequency with applied hydrogen charging led to the huge increase of crack propagation velocity compared to the tests performed in air. To understand such a behaviour in each case and characterize crack mode, the samples were observed using electron back-scattered diffraction (EBSD). It was shown that in air, the fatigue crack propagation involved plastic deformation and the resulting cracks had ductile character. The presence of hydrogen led to more brittle mode of cracking. This effect was also connected with frequency of loading: lower frequency, which assured longer time for hydrogen-crack tip interaction, resulted in the highest crack propagation velocity and the brittle cracking mode with lower amount of plastic deformation. The performed observations indicated that the path of the crack went mostly transgranularly through both austenite and ferrite phases. Phase and grain boundaries were not the preferred paths for crack propagation. KW - Hydrogen KW - Embrittlement KW - Electron backscatter diffraction KW - Steel PY - 2006 SN - 1733-3490 SN - 0004-0770 SN - 0860-7052 VL - 51 IS - 1 SP - 7 EP - 10 AN - OPUS4-38029 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -