High temperature dislocation processes in precipitation hardened crystals investigated by a 3D discrete dislocation dynamics

0480710 - ÚFM 2018 RIV GB eng J - Journal Article
Záležák, Tomáš - Svoboda, Jiří - Dlouhý, Antonín
High temperature dislocation processes in precipitation hardened crystals investigated by a 3D discrete dislocation dynamics.
International Journal of Plasticity. Roč. 97, OCT (2017), s. 1-23. ISSN 0749-6419. E-ISSN 1879-2154
R&D Projects: GA ČR(CZ) GA14-22834S; GA ČR(CZ) GA202/09/2073; GA ČR(CZ) GD106/09/H035; GA MŠMT(CZ) EE2.3.20.0214; GA MŠMT OC 162
EU Projects: European Commission(XE) 309916 - Z-ULTRA
Institutional support: RVO:68081723
Keywords : 3D discrete dislocation dynamics * Dislocations * Strengthening mechanisms * Low angle grain boundaries * Particulate reinforced material
OECD category: Composites (including laminates, reinforced plastics, cermets, combined natural and synthetic fibre fabrics
Impact factor: 5.502, year: 2017

3D discrete dislocation dynamics is employed to investigate motion of general mixed
dislocation segments subjected to high temperature loadings in microstructures with
impenetrable particles. The implementations of the model first address several benchmark
processes including shrinkage of a glissile dislocation loop driven by self-stresses and an
annihilation of mutually interacting co-axial prismatic dislocation loops. In particular, we
show that models of the microstructure with planar and/or translational symmetry
improve efficiency, speed and stability of the calculations. Our simulations then focus on
migration of low angle dislocation boundaries in an array of particles while taking into
account all mutual dislocation-dislocation interactions and the action of an externally
applied stress. The results show for the first time that the migration of tilt dislocation
boundaries in crystals with particles can be associated with threshold stresses. The
calculated thresholds are in a good agreement with experimental threshold stresses that
characterize creep behaviour of precipitation hardened alloys.
Permanent Link: http://hdl.handle.net/11104/0276521