TY  - JOUR
AU  - Samaee, Vahid
AU  - Sandfeld, Stefan
AU  - Idrissi, Hosni
AU  - Groten, Jonas
AU  - Pardoen, Thomas
AU  - Schwaiger, Ruth
AU  - Schryvers, Dominique
TI  - Dislocation structures and the role of grain boundaries in cyclically deformed Ni micropillars
JO  - Materials science and engineering / A
VL  - 769
SN  - 0921-5093
CY  - Amsterdam
PB  - Elsevier
M1  - FZJ-2023-00982
SP  - 138295 -
PY  - 2020
AB  - Transmission electron microscopy and finite element-based dislocation simulations were combined to study the development of dislocation microstructures after cyclic deformation of single crystal and bicrystal Ni micropillars oriented for multi-slip. A direct correlation between large accumulation of plastic strain and the presence of dislocation cell walls in the single crystal micropillars was observed, while the presence of the grain boundary hampered the formation of wall-like structures in agreement with a smaller accumulated plastic strain. Automated crystallographic orientation and nanostrain mapping using transmission electron microscopy revealed the presence of lattice heterogeneities associated to the cell walls including long range elastic strain fields. By combining the nanostrain mapping with an inverse modelling approach, information about dislocation density, line orientation and Burgers vector direction was derived, which is not accessible otherwise in such dense dislocation structures. Simulations showed that the image forces associated with the grain boundary in this specific bicrystal configuration have only a minor influence on dislocation behavior. Thus, the reduced occurrence of “mature” cell walls in the bicrystal can be attributed to the available volume, which is too small to accommodate cell structures.
LB  - PUB:(DE-HGF)16
UR  - <Go to ISI:>//WOS:000500373800018
DO  - DOI:10.1016/j.msea.2019.138295
UR  - https://juser.fz-juelich.de/record/943388
ER  -