| About this Abstract |
| Meeting |
2024 TMS Annual Meeting & Exhibition
|
| Symposium
|
Nanostructured Materials in Extreme Environments II
|
| Presentation Title |
Micro-tensile Behavior of Niobium Single Crystals at Cryogenic Temperatures |
| Author(s) |
Seok-Woo Lee, Shuyang Xiao, Gyuho Song |
| On-Site Speaker (Planned) |
Seok-Woo Lee |
| Abstract Scope |
The effects of cryogenic temperatures on plasticity in micron-sized body-centered-cubic (bcc) metals have not been explored thoroughly under uniaxial tension. In this work, we utilized custom-built in-situ cryogenic micro-tensile testing, transmission electron microscopy, and dislocation simulations to examine the plasticity of bcc niobium micropillars at 50~298 Kelvin. Our study reveals that at low temperature (below 100K), the strong suppression of cross-slip induces dislocation starvation followed by fracture at slip steps. In contrast, at room temperature, the transition from smooth plasticity to discrete plasticity occurs due to the emergence of source-controlled plasticity after necking occurs. The effects of high dislocation density, which is introduced by pre-straining, on flow strength will also be discussed in terms of the creation of high mobility screw dislocations as a possible weakening mechanism. Our study provides a fundamental insight into understanding how plasticity of micron-sized bcc metals differs at extremely cold environment. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Mechanical Properties, Modeling and Simulation, Characterization |