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Title: Tribological performance of monolithic copper thin films during nanowear

Mathematical models suggest that the strain along the film formed by parallel passes of a nanoindentation probe in contact with the film can be either homogenous or heterogeneous, depending on contact pressure and spacing between passes. Here, in this study, a 1 µm copper thin film was worn with a cono-spherical diamond probe with normal loads ranging from 25 to 800 µN and wear box edge lengths of 40, 60, and 80 µm. The nanoindenter counterface was rastered across the surface to mimic dry sliding wear. To determine potential strain field changes, 10-step quasi-static indents (200–2000 µN) were performed using nanoindentation inside the wear boxes created at various loads to determine if a strain field alteration could be observed in changes in hardness of the copper thin film. It was shown that there was a softening effect in the hardness for normal loads < 400 µN used during nanowear compared to the as-deposited copper. Normal loads ≥ 400 µN had a similar or higher hardness than the as-deposited copper. This is believed to have occurred due to a relaxation in the residual stresses created during deposition in the copper thin films at lower loads, which caused a decrease in hardness.more » Conversely, at the higher loads, increased deformation leads to an increase in hardness. Lastly, all of the wear boxes displayed a higher estimated strain hardening exponent than the as-deposited material.« less
Authors:
 [1] ;  [2] ;  [1] ;  [1] ;  [2] ;  [1]
  1. Clemson Univ., SC (United States)
  2. Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Publication Date:
Report Number(s):
LA-UR-17-29361
Journal ID: ISSN 0043-1648
Grant/Contract Number:
AC52-06NA25396
Type:
Accepted Manuscript
Journal Name:
Wear
Additional Journal Information:
Journal Volume: 394-395; Journal Issue: C; Journal ID: ISSN 0043-1648
Publisher:
Elsevier
Research Org:
Los Alamos National Lab. (LANL), Los Alamos, NM (United States)
Sponsoring Org:
USDOE Office of Science (SC). Basic Energy Sciences (BES) (SC-22); USDOE National Nuclear Security Administration (NNSA)
Country of Publication:
United States
Language:
English
Subject:
36 MATERIALS SCIENCE; 77 NANOSCIENCE AND NANOTECHNOLOGY; Nanotribology; Nanoindentation; PVD coatings; Hardness; Sliding wear
OSTI Identifier:
1422927

Schultz, Bradley M., Li, Nan, Economy, David R., Sharp, Julia L., Mara, Nathan A., and Kennedy, Marian S.. Tribological performance of monolithic copper thin films during nanowear. United States: N. p., Web. doi:10.1016/j.wear.2017.10.005.
Schultz, Bradley M., Li, Nan, Economy, David R., Sharp, Julia L., Mara, Nathan A., & Kennedy, Marian S.. Tribological performance of monolithic copper thin films during nanowear. United States. doi:10.1016/j.wear.2017.10.005.
Schultz, Bradley M., Li, Nan, Economy, David R., Sharp, Julia L., Mara, Nathan A., and Kennedy, Marian S.. 2017. "Tribological performance of monolithic copper thin films during nanowear". United States. doi:10.1016/j.wear.2017.10.005. https://www.osti.gov/servlets/purl/1422927.
@article{osti_1422927,
title = {Tribological performance of monolithic copper thin films during nanowear},
author = {Schultz, Bradley M. and Li, Nan and Economy, David R. and Sharp, Julia L. and Mara, Nathan A. and Kennedy, Marian S.},
abstractNote = {Mathematical models suggest that the strain along the film formed by parallel passes of a nanoindentation probe in contact with the film can be either homogenous or heterogeneous, depending on contact pressure and spacing between passes. Here, in this study, a 1 µm copper thin film was worn with a cono-spherical diamond probe with normal loads ranging from 25 to 800 µN and wear box edge lengths of 40, 60, and 80 µm. The nanoindenter counterface was rastered across the surface to mimic dry sliding wear. To determine potential strain field changes, 10-step quasi-static indents (200–2000 µN) were performed using nanoindentation inside the wear boxes created at various loads to determine if a strain field alteration could be observed in changes in hardness of the copper thin film. It was shown that there was a softening effect in the hardness for normal loads < 400 µN used during nanowear compared to the as-deposited copper. Normal loads ≥ 400 µN had a similar or higher hardness than the as-deposited copper. This is believed to have occurred due to a relaxation in the residual stresses created during deposition in the copper thin films at lower loads, which caused a decrease in hardness. Conversely, at the higher loads, increased deformation leads to an increase in hardness. Lastly, all of the wear boxes displayed a higher estimated strain hardening exponent than the as-deposited material.},
doi = {10.1016/j.wear.2017.10.005},
journal = {Wear},
number = C,
volume = 394-395,
place = {United States},
year = {2017},
month = {10}
}