The Nano-UTM is designed to measure the mechanical
properties of small specimens, with a maximum load of
500 mN and a load resolution of 50 nN. Fig. 6(a) shows
the three-point bending configuration of the Nano-
UTM, and Fig. 6(b) shows a magnified view near the
specimen. The span length between the lower contact
points was 1.09 mm. The width of the specimen was
137 lm and the thickness was 57 lm. The maximum loading
distance of the upper fixture was 2 mm. The test was
carried out in load-controlled mode. Static bending tests
were performed at 0.5 mN/s until failure. The static fracture
load when the clogged layer was uppermost was generally
larger than when lowermost. This can be explained
from the geometry of the clogged layer and crack propagation
under tensile loading. During the bending test,
when the clogged layer was lowermost, the clogged layerunderwent tensile loading, and the notches on the clogged
layer functioned as a crack tip enabling the crack to propagate.
When the clogged layer was uppermost, the crack
on the notch of the clogged layer did not propagate,
because it underwent compressive loading. It appears that
these crack tips reduce the fracture strength under tensile
load. The fatigue test was carried out with the clogged
layer uppermost.