Structural Investigation of Size Effects in Plasticity using Indentation ...

A Microstructural investigation of the volume beneath nanoindentations
creep effects, and an unloading part of 17 s, including a holding period of 10 s at
10% of the maximum load was used. Three to five separate indentations were made
for every selected indenter load. The presented results are an average of these
indentations. The error bars in Figures A.8, A.9 and A.12 represent the standard
deviation of each set of measurements.
Additionally, a TEM foil was prepared using the FIB workstation. Again, the
center of the imprint was marked and a protection layer was deposited. By cutting
two trenches on each side of the imprint, a lamella with a thickness of about 2 µm
including the indentation was fabricated. After lifting out, the lamella was thinned
to electron transparency using Ga + ions with a maximum acceleration voltage of
30 or 5 kV. TEM observations were made on a Philips CM12 TEM operating at 120
kV.
A.3 Results
Figure A.2 shows an SEM image of a readily polished cross-section through an
imprint indented with a maximum load of 2.5 mN. On these cross-sections EBSD
mapping was performed and the acquired data were used to calculate the misorientation
angles relative to the undeformed single crystal. To visualize the orientation
changes and consequently the dimensions of the deformation-induced zone, the calculated
angles were plotted in misorientation maps, where crystal orientation changes
can be identified using a color code.
Figure A.2: SEM micrograph showing an inclined view of a readily polished cross-section
through the middle of a 2.5 mN indentation. The image was taken using
secondary electrons.
Figure A.3 shows misorientation maps of sectioned imprints indented at five different
loads. A sketch showing how the indentations were cut is included at the
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