A Study of the Sorption Properties and Changes in the Structure and State of the Ti-25Al-25Nb (at.%) Alloy System Under Thermocyclic Loading
This study is focused on the sorption properties and the changes in the structure and state of Ti-25Al-25Nb (at.%) system alloys under thermal cyclic loading. These samples were produced by combining high-energy processing methods through mechanization and spark plasma sintering in the temperature r...
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| Main Authors: | , , , , , , |
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| Format: | Article |
| Language: | English |
| Published: |
MDPI AG
2025-02-01
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| Series: | Crystals |
| Subjects: | |
| Online Access: | https://www.mdpi.com/2073-4352/15/2/173 |
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| Summary: | This study is focused on the sorption properties and the changes in the structure and state of Ti-25Al-25Nb (at.%) system alloys under thermal cyclic loading. These samples were produced by combining high-energy processing methods through mechanization and spark plasma sintering in the temperature range of 1100–1300 °C, followed by two-stage heat treatment at temperatures of 800 °C and 1250 °C. Thermal cyclic experiments on hydrogen sorption/desorption with samples of the Ti-25Al-25Nb (at.%) system were conducted at the VIKA experimental installation at a saturation temperature of about 500 °C and a degassing temperature of 610 °C. It took about 41 min to reach pressure equilibrium at 500 °C. The hydrogen diffusion coefficient was calculated based on the Barrer formula and was 9.1 × 10<sup>−5</sup> cm<sup>2</sup>/s at 500 °C. The maximum hydrogen content was recorded after the first sorption/desorption cycle and was 1.91 wt%. Due to the multiple thermal cyclic effects in the hydrogen medium, the predominantly two-phase (O + B2) alloy structure underwent transformation to form a new structure (O-AlNbTi<sub>2</sub>). In the phase composition of the Ti-25Al-25Nb (at.%) alloy, the formation of hydrides in the form of independent phases as a result of thermal cycling was not detected. Hydrogen absorption is most likely to be associated with the formation of an interstitial solution based on existing crystalline phases. |
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| ISSN: | 2073-4352 |