About this Abstract |
Meeting |
2023 TMS Annual Meeting & Exhibition
|
Symposium
|
Computational Thermodynamics and Kinetics
|
Presentation Title |
An Electrochemical Repertoire for Triggering Phase Transitions in Insulators: The Case of Monoclinic/Tetragonal Transition in ZrO2 |
Author(s) |
Mostafa Youssef |
On-Site Speaker (Planned) |
Mostafa Youssef |
Abstract Scope |
Phase transitions can be either degrading or desirable. An important transition that is cited to be both degrading and desirable is the monoclinic/tetragonal phase transition in ZrO2. Although it has been mainly discussed as stress-driven, in this work we show that it can also be driven by lattice defects. The free energy of both phases were computed accounting for the contribution of lattice defects under the action of three thermodynamic forces; oxygen chemical potential, impurity chemical potential such as hydrogen, and external electric bias. The results were cast in phase diagrams. Poor oxygen conditions and/or negative electric bias can stabilize tetragonal ZrO2 below its commonly cited stabilization temperature. Meanwhile, hydrogen impurity can reverse the effect and re-stabilize the monoclinic phase. Thus, we provide new insights to the origins of stabilizing the tetragonal phase in oxidized zirconium alloys and new explanations to the mechanism of the water-induced degradation of ZrO2 ceramics. |
Proceedings Inclusion? |
Planned: |
Keywords |
Modeling and Simulation, Phase Transformations, Ceramics |