Interfacial diffusion aided deformation during nanoindentation
- Physics Division, Lawrence Livermore National Laboratory, Livermore, California 94550 (United States)
- BICMR and School of Mathematical Sciences, Peking University, Beijing, China and Department of Mathematics and Program in Applied and Computational Mathematics, Princeton University, Princeton, New Jersey 08544 (United States)
Nanoindentation is commonly used to quantify the mechanical response of material surfaces. Despite its widespread use, a detailed understanding of the deformation mechanisms responsible for plasticity during these experiments has remained elusive. Nanoindentation measurements often show stress values close to a material’s ideal strength which suggests that dislocation nucleation and subsequent dislocation activity dominates the deformation. However, low strain-rate exponents and small activation volumes have also been reported which indicates high temperature sensitivity of the deformation processes. Using an order parameter aided temperature accelerated sampling technique called adiabatic free energy dynamics [J. B. Abrams and M. E. Tuckerman, J. Phys. Chem. B, 112, 15742 (2008)], and molecular dynamics we have probed the diffusive mode of deformation during nanoindentation. Localized processes such as surface vacancy and ad-atom pair formation, vacancy diffusion are found to play an important role during indentation. Our analysis suggests a change in the dominant deformation mode from dislocation mediated plasticity to diffusional flow at high temperatures, slow indentation rates and small indenter tip radii.
- OSTI ID:
- 22611486
- Journal Information:
- AIP Advances, Vol. 6, Issue 7; Other Information: (c) 2016 Author(s); Country of input: International Atomic Energy Agency (IAEA); ISSN 2158-3226
- Country of Publication:
- United States
- Language:
- English
| Crystal Indentation Hardness | book | June 2018 |
Crystal Indentation Hardness
|
text | January 2018 |
Crystal Indentation Hardness
|
journal | January 2017 |
Similar Records
Nanoindentation of Micrograins in Polycrystals under Multiaxial Stress: Control of Abrupt & Stochastic Plastic Events
Indentation Schmid factor and orientation dependence of nanoindentation pop-in behavior of NiAl single crystals