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3D Imaging of a Dislocation Loop at the Onset of Plasticity in an Indented Nanocrystal
journal contribution
posted on 2017-10-19, 21:13 authored by M. Dupraz, G. Beutier, T. W. Cornelius, G. Parry, Z. Ren, S. Labat, M.-I. Richard, G. A. Chahine, O. Kovalenko, M. De Boissieu, E. Rabkin, M. Verdier, O. ThomasStructural quality and stability
of nanocrystals are fundamental
problems that bear important consequences for the performances of
small-scale devices. Indeed, at the nanoscale, their functional properties
are largely influenced by elastic strain and depend critically on
the presence of crystal defects. It is thus of prime importance to
be able to monitor, by noninvasive means, the stability of the microstructure
of nano-objects against external stimuli such as
mechanical load. Here we demonstrate the potential of Bragg coherent
diffraction imaging for such measurements, by imaging in 3D the evolution
of the microstructure of a nanocrystal exposed to in situ mechanical
loading. Not only could we observe the evolution of the internal strain
field after successive loadings, but we also evidenced a transient
microstructure hosting a stable dislocation loop. The latter is fully
characterized from its characteristic displacement field. The mechanical
behavior of this small crystal is clearly at odds with what happens
in bulk materials where many dislocations interact. Moreover, this
original in situ experiment opens interesting possibilities for the
investigation of plastic deformation at the nanoscale.