| About this Abstract |
| Meeting |
2020 TMS Annual Meeting & Exhibition
|
| Symposium
|
Mechanical Behavior at the Nanoscale V
|
| Presentation Title |
Role of Grain Boundaries on Plasticity and Fracture of Nanocrystalline MgAl₂O₄ |
| Author(s) |
Jessica M. Maita, Jacob R. Davis, James Wollmershauser, Edward Gorzkowski, Boris Feigelson, Seok-Woo Lee |
| On-Site Speaker (Planned) |
Jessica M. Maita |
| Abstract Scope |
Transparent materials are used extensively due to their ability to transmit light and provide physical protection from external chemical and mechanical interactions. Transparent nanocrystalline MgAl₂O₄ has been developed with grain sizes ranging 3.7 to 80 nm, the smallest reported. Both nanoindentation and uni-axial micromechanical tests are performed to elucidate the role of high grain boundary density on plasticity and fracture. For nanoindentation, the Hall-Petch (H-P) relation is observed up to 10.5 nm grain size, beyond which an inverse H-P relation is observed. However, microcompression results show that fracture strength keeps increasing as the grain size decreases without inverse H-P relation. HRTEM revealed the presence of amorphous grain boundaries, which play different roles; as fracture initiators in uniaxial compression and plasticity barriers/carriers in nanoindentation. These results provide a better understanding of the mechanical behavior and help improve the design of transparent armor with superior protection capability. |
| Proceedings Inclusion? |
Planned: Supplemental Proceedings volume |