TY - JOUR
T1 - Importance of deformation-induced local orientation distributions for nucleation of recrystallisation
AU - Quey, Romain
AU - Fan, Guo-Hua
AU - Zhang, Yubin
AU - Juul Jensen, Dorte
PY - 2021
Y1 - 2021
N2 - Nucleation in an aluminium tricrystal cold rolled along its columnar
direction, to 40% thickness reduction, is studied. This experimental
configuration was used to obtain the same deformation microstructure
through the sample length, which made it possible to cut it into several
slices of similar microstructures and use these slices differently.
Some slices served to analyse the deformation microstructure and others
to analyse the annealing microstructure. Nucleation developed only in
one of the three crystals and not at grain boundaries. The relationship
between the crystallographic orientations and the local density of
nuclei and different attributes of the parent, deformation
microstructure was then analysed. As generally presumed, the nuclei were
observed to inherit orientations from the parent matrix. Much more
surprisingly, the stored energy alone, which is often considered as the
driving force for recrystallisation nucleation, was found not to provide
a reliable criterion for recrystallisation nucleation in the
investigated sample. Instead, the density of nuclei was the highest
where the substructure is composed of sharp bands, which correspond to
regions of highly anisotropic orientation distributions. A new energy
criterion for recrystallisation nucleation is proposed, which is called
“primary stored energy” and depends on the stored energy and the
anisotropy of the orientation distribution.
AB - Nucleation in an aluminium tricrystal cold rolled along its columnar
direction, to 40% thickness reduction, is studied. This experimental
configuration was used to obtain the same deformation microstructure
through the sample length, which made it possible to cut it into several
slices of similar microstructures and use these slices differently.
Some slices served to analyse the deformation microstructure and others
to analyse the annealing microstructure. Nucleation developed only in
one of the three crystals and not at grain boundaries. The relationship
between the crystallographic orientations and the local density of
nuclei and different attributes of the parent, deformation
microstructure was then analysed. As generally presumed, the nuclei were
observed to inherit orientations from the parent matrix. Much more
surprisingly, the stored energy alone, which is often considered as the
driving force for recrystallisation nucleation, was found not to provide
a reliable criterion for recrystallisation nucleation in the
investigated sample. Instead, the density of nuclei was the highest
where the substructure is composed of sharp bands, which correspond to
regions of highly anisotropic orientation distributions. A new energy
criterion for recrystallisation nucleation is proposed, which is called
“primary stored energy” and depends on the stored energy and the
anisotropy of the orientation distribution.
U2 - 10.1016/j.actamat.2021.116808
DO - 10.1016/j.actamat.2021.116808
M3 - Journal article
SN - 1359-6454
VL - 210
JO - Acta Materialia
JF - Acta Materialia
M1 - 116808
ER -