About this Abstract |
Meeting |
2022 TMS Annual Meeting & Exhibition
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Symposium
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30 Years of Nanoindentation with the Oliver-Pharr Method and Beyond
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Presentation Title |
Size-dependent Indentation Behavior and Geometrically Necessary Dislocation Structures of Single-crystalline Tungsten |
Author(s) |
Jin Wang, Ruth Schwaiger |
On-Site Speaker (Planned) |
Jin Wang |
Abstract Scope |
The hardness of single-crystalline tungsten exhibits a pronounced dependence on the indentation depth, which is know as the indentation size effect (ISE). For the case of single-crystalline tungsten, the increase of the hardness with decreasing depth cannot be described by the Nix-Gao model over the full depth range. The model overestimates the hardness for depths <300 nm. Assuming different dislocation distributions in the different depth regimes, the observed behavior can be well captured. Furthermore, the geometrically necessary dislocation (GND) structures were analyzed based on plane strain indentation and transmission Kikuchi diffraction. The different characteristics of the GND distributions determined using the Nye-Kröner tensor can be explained by the evolving kink-pair structure with increasing indentation depth. Our findings corroborate the two regimes of the ISE. In this presentation, we will discuss the evolution of the GND structures and introduce a modification to the classical Nix-Gao model capturing the full depth regime. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, Mechanical Properties, |