Characterization of indentation size effects in epoxy

F. Alisafaei; Chung Souk Han; Nishant Lakhera

doi:10.1016/j.polymertesting.2014.08.012

Characterization of indentation size effects in epoxy

F. Alisafaei, Chung Souk Han, Nishant Lakhera

Research output: Contribution to journal › Article › peer-review

49 Scopus citations

Abstract

Nanoindentation tests were conducted at different indentation depths, ranging from 3000 to 30 nm, to study the characteristics of indentation size effects in epoxy. Taking the effects of tip imperfection/bluntness into account, nanoindentation tests performed with a three-sided Berkovich tip exhibited strong increases in the hardness with decreasing indentation depth. However, comparative testing with a spherical tip with a radius of 250 microns, showed no changes in the material properties with respect to the distance from the surface. Consequently, different deformation mechanisms must be present in the indentation tests with Berkovich and spherical tips, suggesting effects related to second order gradients of the displacement (such as strain or rotation gradients), which increase with a Berkovich tip but essentially stay constant with a spherical tip when indentation depth decreases.

Original language	English (US)
Pages (from-to)	70-78
Number of pages	9
Journal	Polymer Testing
Volume	40
DOIs	https://doi.org/10.1016/j.polymertesting.2014.08.012
State	Published - 2014
Externally published	Yes

All Science Journal Classification (ASJC) codes

Polymers and Plastics
Organic Chemistry

Keywords

Length scale dependent deformation
Nanoindentation
Polymers

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10.1016/j.polymertesting.2014.08.012

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title = "Characterization of indentation size effects in epoxy",

abstract = "Nanoindentation tests were conducted at different indentation depths, ranging from 3000 to 30 nm, to study the characteristics of indentation size effects in epoxy. Taking the effects of tip imperfection/bluntness into account, nanoindentation tests performed with a three-sided Berkovich tip exhibited strong increases in the hardness with decreasing indentation depth. However, comparative testing with a spherical tip with a radius of 250 microns, showed no changes in the material properties with respect to the distance from the surface. Consequently, different deformation mechanisms must be present in the indentation tests with Berkovich and spherical tips, suggesting effects related to second order gradients of the displacement (such as strain or rotation gradients), which increase with a Berkovich tip but essentially stay constant with a spherical tip when indentation depth decreases.",

keywords = "Length scale dependent deformation, Nanoindentation, Polymers",

author = "F. Alisafaei and Han, {Chung Souk} and Nishant Lakhera",

year = "2014",

doi = "10.1016/j.polymertesting.2014.08.012",

language = "English (US)",

volume = "40",

pages = "70--78",

journal = "Polymer Testing",

issn = "0142-9418",

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TY - JOUR

T1 - Characterization of indentation size effects in epoxy

AU - Alisafaei, F.

AU - Han, Chung Souk

AU - Lakhera, Nishant

PY - 2014

Y1 - 2014

N2 - Nanoindentation tests were conducted at different indentation depths, ranging from 3000 to 30 nm, to study the characteristics of indentation size effects in epoxy. Taking the effects of tip imperfection/bluntness into account, nanoindentation tests performed with a three-sided Berkovich tip exhibited strong increases in the hardness with decreasing indentation depth. However, comparative testing with a spherical tip with a radius of 250 microns, showed no changes in the material properties with respect to the distance from the surface. Consequently, different deformation mechanisms must be present in the indentation tests with Berkovich and spherical tips, suggesting effects related to second order gradients of the displacement (such as strain or rotation gradients), which increase with a Berkovich tip but essentially stay constant with a spherical tip when indentation depth decreases.

AB - Nanoindentation tests were conducted at different indentation depths, ranging from 3000 to 30 nm, to study the characteristics of indentation size effects in epoxy. Taking the effects of tip imperfection/bluntness into account, nanoindentation tests performed with a three-sided Berkovich tip exhibited strong increases in the hardness with decreasing indentation depth. However, comparative testing with a spherical tip with a radius of 250 microns, showed no changes in the material properties with respect to the distance from the surface. Consequently, different deformation mechanisms must be present in the indentation tests with Berkovich and spherical tips, suggesting effects related to second order gradients of the displacement (such as strain or rotation gradients), which increase with a Berkovich tip but essentially stay constant with a spherical tip when indentation depth decreases.

KW - Length scale dependent deformation

KW - Nanoindentation

KW - Polymers

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DO - 10.1016/j.polymertesting.2014.08.012

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VL - 40

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EP - 78

JO - Polymer Testing

JF - Polymer Testing

ER -

Characterization of indentation size effects in epoxy

Abstract

All Science Journal Classification (ASJC) codes

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