About this Abstract |
Meeting |
2024 TMS Annual Meeting & Exhibition
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Symposium
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Mechanical Behavior at the Nanoscale VII
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Presentation Title |
Phase Instability and Strengthening Induced by Oxygen Interstitials in BCC Ti-Nb Alloys |
Author(s) |
Florent Mignerot, Ravit Silverstein, Nicoló Maria della Ventura, Carlos G Levi, Tresa M Pollock, Daniel S Gianola |
On-Site Speaker (Planned) |
Florent Mignerot |
Abstract Scope |
BCC refractory alloys are of renewed interest for their mechanical properties, yet interstitial elements may promote phase instabilities. Resulting new microstructures can enhance the alloys’ mechanical response, but key mechanisms are not fully understood. This work investigates the role of interstitial oxygen (~ 1 at.%) on phase transformations and mechanical behavior in Ti-Nb alloys. Oxygen infusion drives phase separation characterized by two distinct but interrelated pathways: spinodal decomposition (SD) and a two-phase lamellar structure. Evolution of the microstructure occurs via coarsening of the SD region, associated with variations in the modulation wavelength, or a transformation to the HCP/BCC lamellar structure. Site-specific nanoindentation reveals a wavelength dependence of the hardness, which ranges from 4.5 to 7.5 GPa. In situ micro-tensile tests performed on SD and lamellar structures show plastic activation and tensile strengths up to 3 GPa. The impact of interstitial oxygen on strengthening and deformation mechanisms will be discussed. |
Proceedings Inclusion? |
Planned: |
Keywords |
Mechanical Properties, Phase Transformations, |