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 |
Characterization of Grain Boundaries in Geological Materials Using Micromechanical Testing |
Author(s) |
Diana Avadanii, Lars Hansen, Katharina Marquardt, Ed Darnbrough, David Armstrong, Angus Wilkinson |
On-Site Speaker (Planned) |
Diana Avadanii |
Abstract Scope |
Olivine is a key geological material influencing large-scale, long-term planetary deformation processes on rocky planets. In the past three decades, nanoindentation has been deployed as a powerful technique to study olivine mechanics. Previous studies have emphasized the importance of grain-size effects. However, most of our understanding of the role of grain boundaries in deformation of olivine is inferred from comparison of experiments on single crystals to experiments on polycrystalline samples.
To directly observe and quantify the mechanical properties of olivine grain boundaries, we conduct micromechanical tests on well characterised bicrystals. We perform room-temperature spherical and Berkovich nanoindentation and in-situ micropillar tests at 700°C. We observe that certain grain-boundary configurations act as sites for initiating microplasticity. The experiments demonstrate that, under these conditions, grain boundaries are stronger than the grain interior. These observations provide a basis for incorporating grain-boundary effects in the next generation of constitutive models for geological materials. |
Proceedings Inclusion? |
Planned: |
Keywords |
Characterization, Mechanical Properties, Other |