| About this Abstract |
| Meeting |
MS&T21: Materials Science & Technology
|
| Symposium
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Grain Boundaries, Interfaces, and Surfaces in Ceramics: Fundamental Structure—Property—Performance Relationships
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| Presentation Title |
Hall-petch Behavior in Stoichiometric and Al-rich Nanocrystalline ZnAl2O4 |
| Author(s) |
Luis Enrique Sotelo Martin, Ricardo H.R. Castro |
| On-Site Speaker (Planned) |
Luis Enrique Sotelo Martin |
| Abstract Scope |
Nanocrystalline ZnAl2O4 is a prime candidate for next-generation armored windows due to its enhanced mechanical properties and high thermal conductivity relative to other metal oxides (e.g. MgAl2O4, Al2O3, and ALON). Elevated hardness in nanocrystalline oxides has been widely attributed to Hall-Petch strengthening, but there exist conflicting reports on the low grain size limit to this relationship even within the same material system. This study provides a new perspective on the Hall-Petch inversion in nanocrystalline ceramics by showcasing the role of stoichiometry in grain size strengthening. Mechanical behavior was investigated in stoichiometric and Al-rich ZnAlxO4 (x = 2.01, 2.87) synthesized by reverse-strike co-precipitation and consolidated using spark plasma sintering. A Hall-Petch breakdown in Vickers hardness was observed only in stoichiometric ZnAl2O4 at grain sizes below 19 nm. These results demonstrate improved control of the Hall-Petch behavior in nanocrystalline ZnAl2O4 that can be applied in nanoceramic processing and tuning of mechanical properties. |