Deformation crossover: from nano- to mesoscale.
In situ synchrotron and neutron diffraction were used to study deformation mechanisms in Ni over a broad range of grain sizes. The experimental data show that unlike in coarse-grained metals, where the deformation is dominated by dislocation slip, plastic deformation in nanocrystalline Ni is mediated by grain-boundary activities, as evidenced by the lack of intergranular strain and texture development. For ultrafine-grained Ni, although dislocation slip is an active deformation mechanism, deformation twinning also plays an important role, whose propensity increases with the grain size.
Cheng
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S
Neutron Scattering Science Division, Oak Ridge National Laboratory, Oak Ridge, Tennessee 37831, USA.
Stoica
A D
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Wang
X-L
XL
Ren
Y
Y
Almer
J
J
Horton
J A
JA
Liu
C T
CT
Clausen
B
B
Brown
D W
DW
Liaw
P K
PK
Zuo
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