The Influence Of Surface Roughness In Micro Indentation
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Date
2013-11
Authors
Chuah, Hun Guan
Journal Title
Journal ISSN
Volume Title
Publisher
Universiti Sains Malaysia
Abstract
In micro indentation, scale dependent behavior is encountered as the smaller
indentation size produces higher hardness value which is known as indentation size
effect (ISE). For small scale indentation, the indent size and the contact asperity size
are relatively small if the deformed surface is “rough”. Therefore, the resistance
attributed from the friction interface associated with surface roughness alters the
deformation severity which contributes to the change of indent size. The effect of
surface roughness on ISE in micro indentation is studied using the proportional
specimen resistance (PSR) model. With the basis of PSR model, a new normalized
hardness model 1
2
1 +
+
=
a d
c c R
H
H o a
o
is developed to show the relationship between
the ISE and the surface roughness. This study shows that the Meyer’s index n
increases with rougher surface. From the analysis using the PSR model, rougher
surface gives higher proportional specimen resistance due to the increase of
coefficient related to proportional specimen resistance a1. Subsequently, the
normalized hardness value increases with roughness. In addition, a surface roughness
dependent friction model 2
2
2
*
2
0 )
2.46
0.39
) (
2.46
(1
p
p
h R
R
h R
h
H
c a
a
c c
o α
μ
−
−
+
−
+
= is
developed to predict friction coefficient and the model shows that the rougher
surface gives higher value of friction coefficient in micro indentation.
Description
Keywords
Surface Roughness , Micro Indentation