Synthesis and Processing of Materials: Phase transformations in ceramics and related materials, far from equilibrium, under the influence of an electric field.
Abstract
The technical objective of the proposed effort is to establish the fundamental mechanisms governing phase transformations far from equilibrium under the application of moderate electric fields and temperatures. The proposed effort is motivated by the recent discovery of phase transformations, and changes in crystal structure, under the influence of electrical fields that could not be predicted from traditional phase equilibria and diffusion kinetics. The proposed research will seek to provide a robust atomistic understanding of these effects through experiments, and from first principles calculations of defect chemistry, phase stability, and interface-matrix interactions. More specifically, the work will investigate the phase change in tetragonal 3YSZ, the change in crystal structure of TiO2, in addition to accelerated reactions and sintering broadly. The 3YSZ work will focus on the uncertain structure of the recently discovered ÒnewÓ phase resulting from this transformation, determining the atomic motions and compositions necessary to accomplish this change, and determining the role of defects in this phenomenon. The TiO2 work will focus on the development of texture in the local crystal orientation and the dynamic changes in the constitution of crystal planes during this transformation. The accelerated reactions and sintering portion of the work will focus on identifying unique atomistic mechanisms for sintering that help explain the apparent departure from classic reaction rates. Flash experiments will be conducted with both DC and AC fields, and synchrotron experiments will be conducted at both the Advanced Photon Source at the Argonne National Laboratory and the Brookhaven National Laboratory to maximize beam time. The proposed computational modeling will span both classical models and first-principles calculations to help determine the physical phenomena governing these unique transformations.
Document Details
- Document Type
- DoD Grant Award
- Publication Date
- Apr 18, 2017
- Source ID
- W911NF1610200
Entities
People
- Rishi Raj
Organizations
- Army Contracting Command
- United States Army
- University of Colorado Boulder