Strengthening mechanisms of different oxide particles in 9Cr ODS steel at high temperatures

0506860 - ÚFM 2020 RIV CH eng J - Journal Article
Šiška, Filip - Stratil, Luděk - Hadraba, Hynek - Fintová, Stanislava - Kuběna, Ivo - Horník, Vít - Husák, Roman - Bártková, Denisa - Záležák, Tomáš
Strengthening mechanisms of different oxide particles in 9Cr ODS steel at high temperatures.
Materials Science and Engineering A Structural Materials Properties Microstructure and Processing. Roč. 732, AUG (2018), s. 112-119. ISSN 0921-5093. E-ISSN 1873-4936
R&D Projects: GA ČR(CZ) GA14-25246S; GA ČR GJ15-21292Y
Institutional support: RVO:68081723
Keywords : stress-relaxation * ferritic alloy * microstructure * behavior * dependence * y2o3 * cr * precipitation * kinetics * Iron alloys * Stress relaxation measurements * Modelling/simulations * Plasticity
OECD category: Materials engineering
Impact factor: 4.081, year: 2018
Method of publishing: Limited access
https://www.sciencedirect.com/science/article/pii/S1044580318335915?via%3Dihub

The influence of different oxide particles on deformation mechanisms of 9Cr ODS steels at temperatures 400-600 degrees C is tested. Two ODS variants with Al2O3 and Y2O3 dispersed particles respectively and one variant without particles have been prepared by powder metallurgy. The deformation mechanisms are investigated by the tensile and stress-relaxation test at temperatures 400 degrees C and 600 degrees C. The analysis is based on a comparison of athermal and thermal stress components of the flow stress, apparent activation volume and a strain rate hardening. Microstructural parameters are evaluated upon SEM and TEM observations. The contributions of different strengthening mechanisms are assessed using the Taylor, Hall-Petch, dispersed barrier and Orowan models. Alumina particles provide the highest strengthening which can be explained by the stress decrease around the particles induced by a high difference between Young's moduli of alumina and ferritic matrix. This stress field can trap the dislocation in the vicinity of particles. Due to this stress decrease, alumina particles provide strengthening even at 600 degrees C in contrast to yttria particles that lose their effect due to their overcoming by a non-conservative motion of dislocations.
Permanent Link: http://hdl.handle.net/11104/0300088