A Numerical Analysis of Deformation Processes in Oxide Dispersion-Strengthened Materials – Influence of Dislocation-Particle Interactions

0467048 - ÚFM 2018 RIV CH eng C - Conference Paper (international conference)
Záležák, Tomáš - Šiška, Filip - Stratil, Luděk - Luptáková, Natália - Šmíd, Miroslav - Bártková, Denisa - Svoboda, Jiří - Dlouhý, Antonín
A Numerical Analysis of Deformation Processes in Oxide Dispersion-Strengthened Materials – Influence of Dislocation-Particle Interactions.
Materials Structure & Micromechanics of Fracture VIII. Zürrich: Trans Tech Publications, 2017 - (Šandera, P.), s. 106-109. Solid State Phenomena, 258. ISBN 978-3-03835-626-4. ISSN 1662-9779.
[MSMF8. International Conference on Materials Structure and Micromechanics of Fracture /8./. Brno (CZ), 27.06.2016-29.06.2016]
R&D Projects: GA ČR(CZ) GA14-22834S; GA ČR GJ15-21292Y
Institutional support: RVO:68081723
Keywords : 3D discrete dislocation dynamics * metal matrix composites * precipitate hardening * high temperature creep
OECD category: Materials engineering

A recently developed 3D discrete dislocation dynamics (DDD) model is employed to study
kinetics of dislocation ensembles subjected to high temperature creep in microstructures of metal
matrix composites. We particularly focus on a migration of low angle tilt boundaries in a field of rigid
impenetrable particles. This type of dislocation boundaries represents a typical microstructural feature
mediating plastic deformation during the high temperature loadings.
The article compares results of numerical studies that considered distinct dislocation-particle in-
teractions in order to describe the response of dislocation structure to the applied stress. The results
suggest that, regardless the details related to the dislocation-particle interactions, a critical applied
stress always exists, below which the boundary migration process ceases [1, 2]. The existence of crit-
ical threshold is confirmed by creep tests of ODS materials. This critical threshold, contrary to the
classical Orowan stress, is proportional to the dislocation density. The displacements of individual
dislocation segments on the micro-scale level reflect the changes in the dislocation-particle interac-
tions quite sensitively. At the macro-scale level, the overall strain rate, which averages out velocities of
all the individual dislocation segments, is also significantly influenced by the changes in dislocation-
particle interaction.
Permanent Link: http://hdl.handle.net/11104/0271178