About this Abstract |
Meeting |
MS&T24: Materials Science & Technology
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Symposium
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Advances in High-Temperature Oxidation and Degradation of Materials for Harsh Environments: A SMD and FMD Symposium Honoring Brian Gleeson
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Presentation Title |
Understanding the High Temperature Oxidation and Interdiffusion Behaviour of Tantalum Alloyed β-Based Titanium Aluminide |
Author(s) |
Shivansh Mehrotra, Kushal Samanta, Dibyajyoti Ghosh, Sangeeta Santra |
On-Site Speaker (Planned) |
Shivansh Mehrotra |
Abstract Scope |
This work focuses on the positive impact of addition of tantalum (Ta) in the β-based (Ti, Al) solid solution phase, analyzing its effects on oxidation and interdiffusion behaviour. The inclusion of Ta in the β-phase results in improved oxidation resistance by preventing the growth of a porous and non-adherent oxide, rutile (TiO2), as confirmed by XPS and TEM analysis of isothermally oxidized alloys. First-principles based simulations suggested that the prevention of TiO2 formation can be attributed to the increased formation energy of oxygen vacancies in TiO2 due to the addition of Ta. Moreover, a comprehensive study on pseudo-binary diffusion has demonstrated that a higher Ta content in β-(Ti, Al) leads to an increase in the interdiffusion coefficient within the temperature range of 1000-1200 °C. This increase in the coefficient can be understood by considering the changes in defect kinetics within the Ta-alloyed β-phase and the associated thermodynamic driving forces. |