About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
|
Symposium
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30 Years of Nanoindentation with the Oliver-Pharr Method and Beyond
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Presentation Title |
On the Plastic Deformation Mechanisms Operating in High Purity Indium at Small Length Scales and High Homologous Temperatures |
Author(s) |
Fereshteh Mallakpour, Stephen A. Hackney, Erik G. Herbert |
On-Site Speaker (Planned) |
Fereshteh Mallakpour |
Abstract Scope |
Nanoindentation and electron microscopy have been used to examine the plastic deformation mechanisms operating in high purity indium at high homologous temperatures and length scales where the probability of finding mobile dislocations and/or active dislocation multiplication sources is low. Load-displacement data obtained using the Berkovich and a spherical (ellipsoid-like) indenter tip show a distinctive and abrupt transition in the flow mechanism. Before the transition, the residual hardness impressions from both indenter tip geometries exhibit significant pile-up and the stress exponent for creep is found to be approximately 3.5. Post-transition, the residual hardness impressions show no significant pile-up and the stress exponent increases from 3.5 to approximately 9 for the Berkovich and 13 for the sphere. A simple model is introduced to rationalize the stress exponent of 3.5 based on stress directed interface diffusion. Post-transition, the higher stress exponent is rationalized by dislocation mediated flow. |
Proceedings Inclusion? |
Planned: |