| About this Abstract |
| Meeting |
2025 TMS Annual Meeting & Exhibition
|
| Symposium
|
Advances in Ceramic Materials and Processing
|
| Presentation Title |
Transformation-Induced Strains in Glass-Ceramics Through Complex Thermo-Mechanical Histories |
| Author(s) |
Kenneth Cundiff, Kevin Strong, Thomas Diebold, Brian Lester, Kevin Long |
| On-Site Speaker (Planned) |
Kenneth Cundiff |
| Abstract Scope |
Lithium silicate glass-ceramics exhibit higher average coefficients of thermal expansion (CTE) relative to their base glasses, which makes them desirable for hermetic seals for electrical feedthroughs within metal housings. These higher CTEs arise from silica polymorphs (cristobalite, quartz) embedded in the base glass that undergo a reversible solid-to-solid phase transformation (phase inversion). Although a glass-ceramic to metal seal may be under significant residual stress, the strains during phase transformation have not been thoroughly studied except under stress-free conditions. In this work, discovery experiments are executed to characterize transformation-induced strains in a glass-ceramic under a wide range of thermo-mechanical paths. Iso-stress temperature sweeps uncover the dependence of the transformation temperature and strain magnitude on the stress. The ability of stress to induce phase transformation is explored using iso-temperature loading and temperature cycles before and after loading. Experimental results are used to validate a constitutive model combining viscoelasticity and phase transformation. |
| Proceedings Inclusion? |
Planned: |
| Keywords |
Characterization, Modeling and Simulation, |