Title: A numerical study on pile-up in nanoindentation creep

Authors: S. Mandal, S. Kose, A. Frank, A.A. Elmustafa

Addresses: Department of Mechanical Engineering, Old Dominion University, Norfolk, VA 23529, USA; Applied Research Center, Old Dominion University, Jefferson Lab, Newport News, VA 23606, USA. ' Department of Mechanical Engineering, Old Dominion University, Norfolk, VA 23529, USA; Applied Research Center, Old Dominion University, Jefferson Lab, Newport News, VA 23606, USA. ' Department of Mechanical Engineering, Old Dominion University, Norfolk, VA 23529, USA; Applied Research Center, Old Dominion University, Jefferson Lab, Newport News, VA 23606, USA. ' Department of Mechanical Engineering, Old Dominion University, Norfolk, VA 23529, USA; Applied Research Center, Old Dominion University, Jefferson Lab, Newport News, VA 23606, USA

Abstract: In this paper, we simulate materials of variable hardness, work hardening exponent, χ = ∂1nσ/∂1nε of 0.1–0.3 and a strain rate sensitivity of von Mises stress, vσ = ∂1nσ/∂1nε of 0.08–0.16 to estimate pile-ups and sink-ins during indentation creep and compare the results with literature data. We report that materials pile-up for vΗ/vσ ≥ 1.0 and sink-in for vΗ/vσ < 1.0, vσ is the strain rate sensitivity of the hardness. vΗ/vσ approaches 1 for small Η/Ε*, i.e., soft materials and deformation is dominated by pile-up, whereas when vΗ/vσ approaches 0 for large Η/Ε* corresponds to purely elastic deformation which is apparently dominated by sink-in in a manner prescribed by Hertzian contact mechanics.

Keywords: nanoindentation; creep; pile-up; hardness measurement; ABAQUS.

DOI: 10.1504/IJSURFSE.2008.018967

International Journal of Surface Science and Engineering, 2008 Vol.2 No.1/2, pp.41 - 51

Published online: 26 Jun 2008 *

Full-text access for editors Access for subscribers Purchase this article Comment on this article