About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
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Symposium
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Deformation Mechanisms, Microstructure Evolution, and Mechanical Properties of Nanoscale Materials
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Presentation Title |
G-12: Nanomechanical Testing of Limited Slip System Materials: Deformation and Fracture |
Author(s) |
Hugh P. Grennan, David F Bahr |
On-Site Speaker (Planned) |
Hugh P. Grennan |
Abstract Scope |
Organic crystalline materials, commonly used in energetics and pharmaceuticals, are typically non-cubic materials with limited slip systems. Nanoindentation is conducive to measuring modulus, hardness, and fracture behavior in these solids, where individual crystals with sub-mm dimensions are commonly used in composite systems. We examine two monoclinic material systems with the same crystal structure but different slip behavior. Post nanoindentation scanning probe microscopy shows impressions which are non-conformal to pyramidal indenters in an azoxyfurazan-based crystal (modulus and hardness approximately 14 GPa and 660 MPa, respectively), whereas a similar modulus and hardness nitrosamine-based crystal (about 11 GPa and 430 MPa) showed post-indent impressions that correspond to the shape of the probe. Both materials show minor evidence of yield phenomena, suggesting similar initial dislocation densities. Multi-angle probes were then used to compare the likelihood of indent-induced fracture and the propensity for fracture appears to increase in molecular organics with fewer active slip systems. |
Proceedings Inclusion? |
Planned: |
Keywords |
Mechanical Properties, |