W911NF-12-R-0012-03: Grain Boundary Polarization to Increase Toughness of Nanocrystalline Transparent Spinel
Abstract
The main goal of this STIR project was to develop fundamental understanding on the toughness of nanocrystalline ceramics, in particular spinel and zirconia, and explore new energy absorption mechanisms to promote enhanced performance. Two main mechanisms were proposed: (1) Grain boundary strengthening by grain boundary energy decrease; and (2) Polarization of grain boundaries by utilizing electric fields. Despite the short period of the project, we were able to stress the first mechanism and demonstrate its efficacy in increasing toughness of zirconia by about 20%. This opens a new research frontier that shall be explored in other oxides. Moreover, we could address the second mechanism, which should that although polarization can be induced by electric fields in the complex oxide MgAl2O4, the resulting effect on mechanical properties is too small. The results are consolidated in 1 submitted paper, and 4 other manuscripts in preparation (one already at near-submission stage). Note that in the context of the very short time available to accomplish this project (9 months), we consider this a great achievement. The papers will be submitted, but the limited funds to continue the project are certainly delaying the outcome reporting.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Feb 14, 2019
- Source ID
- W911NF1710026
Entities
People
- Ricardo Castro
Organizations
- Army Contracting Command
- United States Army
- University of California, Davis