Small fatigue crack propagation in Y2O3 strengthened steels

0434858 - ÚFM 2015 RIV NL eng J - Journal Article
Hutař, Pavel - Kuběna, Ivo - Ševčík, Martin - Šmíd, Miroslav - Kruml, Tomáš - Náhlík, Luboš
Small fatigue crack propagation in Y2O3 strengthened steels.
Journal of Nuclear Materials. Roč. 452, 1-3 (2014), s. 370-377. ISSN 0022-3115. E-ISSN 1873-4820
R&D Projects: GA MŠMT(CZ) EE2.3.30.0063; GA MŠMT(CZ) ED1.1.00/02.0068; GA ČR(CZ) GP13-28685P
Institutional support: RVO:68081723
Keywords : oxide dispersion strengthened steel * small fatigue crack * J-integral * fatigue life prediction
Subject RIV: JL - Materials Fatigue, Friction Mechanics
Impact factor: 1.865, year: 2014

This paper is focused on two type of Y2O3 strengthened steels (Fe–14Cr ODS and ODS-EUROFER). Small fatigue crack propagation was experimentally measured using special small cylindrical specimens (diam-meter 2 and 2.6 mm) with shallow notch grinded in the gauge length. In the middle of this notch, a pre-crack of length of 50 microns was fabricated using a focused ion beam technique. Fatigue crack growth rate was measured for different applied total strain amplitudes and described using plastic part of the J-integral. Obtained results were compared with published data of EUROFER 97. The effect of the oxide dispersion on small fatigue crack propagation was found rather insignificant. Ferritic Fe–14Cr ODS steel shows more brittle behaviour, i.e. for the same cyclic plasticity, characterised by the plastic part of the J-integral, the small cracks grow faster. A new methodology for residual lifetime prediction of structures containing physically small cracks, based on plastic part of the J-integral, is presented.
Permanent Link: http://hdl.handle.net/11104/0238850