0465625 - ÚFM 2017 RIV IN eng J - Článek v odborném periodiku
Kuběna, Ivo - Kruml, Tomáš - Polák, Jaroslav
Behaviour of ODS Steels in Cyclic Loading.
Transactions of The Indian Institute of Metals. Roč. 69, č. 2 (2016), s. 309-313. ISSN 0972-2815. E-ISSN 0975-1645.
[International Conference on CREEP, FATIGUE and CREEP-FATIGUE INTERACTION /7./. Kalpakkam, 19.01.2016-22.01.2016]
Grant CEP: GA MŠMT(CZ) ED1.1.00/02.0068; GA ČR GA15-08826S
Institucionální podpora: RVO:68081723
Klíčová slova: ODS steels * low cycle fatigue * small fatigue crack * microstructure
Kód oboru RIV: JL - Únava materiálu a lomová mechanika
Impakt faktor: 0.533, rok: 2016
http://link.springer.com/article/10.1007/s12666-015-0814-3

The low cycle fatigue behaviour of several high chromium oxide dispersion strengthened (ODS) steels prepared by powder metallurgy was studied in a detailed way. Studied ODS steels were divided into two groups, ultrafine grained (UFG—grain size under 1 μm) and coarse grained (CG—grain size of 200 μm). Microstructure of as received state of individual steels was observed by means of SEM and TEM. Cyclic hardening/softening curves were measured at room temperature and at 650 °C. It is shown that 0.3 wt% of oxide nanoparticles strengthen the materials substantially and reduces the cyclic softening compared to non-ODS steels. Cyclic softening was measured in CG steel and in UFG ODS ferritic/martensitic steel at room temperature, but stable cyclic behaviour was observed at 650 °C. UFG ODS ferritic steels exhibited stable cyclic behaviour at both testing temperatures. Derived Wöhler and Coffin-Manson curves were measured and substantial differences in fatigue life were revealed. Crack initiation mechanisms and fatigue crack growth rate were analysed. The crack initiation mechanism differs for studied steels, as well as fatigue crack growth rate. The relative length of nucleation and propagation stages of the fatigue life is discussed for individual materials. TEM observations revealed differences in microstructure evolution during fatigue loading in particular steels. All results are thoroughly discussed to explain differences in fatigue life of studied steels.
Trvalý link: http://hdl.handle.net/11104/0264126