Effects of small indenter size and its position on incipient yield loading during nanoindentation
W. S. Yu and S. P. Shen
Materials Science and Engineering A, 526, 211-218 (2009).

ABSTRACT
he object of this paper is to study the effects of small indenter sizes and its
positions on yield loading corresponding to onset plasticity during
nanoindentation into a Cu(1 1 1) film surface with a small frictionless
hard-cylindrical indenter by using the quasicontinuum method (QCM). The critical
incipient yield loadings for some specified values of film thickness with
different small indenter sizes and positions of indenter are compared. It is
found that, both the indenter sizes and the tiny shift of contact positions
between the two neighboring surface atoms along the [(1) over bar (1) over bar
2] direction have significant effects on the critical yield loadings and the
response of force on the indenter. In the meantime, results reveal that both the
yield loadings and displacement of indenter corresponding to the incipient
plasticity during nanoindentation are not constants but vary in the wave-like
form with gradually shifting the initial positions of indenter along the [(1)
over bar (1) over bar 2] direction, and so does the variation of forces on the
indenter in the horizontal direction.