Effect of surface roughness on nanoindentation test of thin films
W. G. Jiang, J. J. Su and X. Q. Feng
Engineering Fracture Mechanics, 75, 4965-4972  (2008).

ABSTRACT
By using the two-dimensional quasicontinuum method, the nanoindentation process
on a single crystal copper thin film with surface roughness is simulated to
study the effect of surface morphology on the measurements of mechanical
parameters. The nanohardness and elastic modulus are calculated according to
Oliver-Pharr's method. The obtained results show a good agreement with relevant
theoretical and experimental results. It is found that surface roughness has a
significant influence on both the nanohardness and elastic modulus of thin films
determined from nanoindentation tests. The effect of such factors as the
indenter size, indentation depth and surface morphology are also examined. To
rule out the influence of surface morphology, the indentation depth should be
much greater than the characteristic size of surface roughness and a reasonable
indenter size should be chosen. This study is helpful for identifying the
mechanical parameters of rough thin films by nanoindentation test and designing
nanoindentation experiments.