The Effect of Hydrogen on Martensite Transformations and the State of Hydrogen Atoms in Binary TiNi-Based Alloy with Different Grain Sizes
| Autor: | Aleksandr Lotkov, Ivan Rodionov, V.N. Kudiiarov, Yerzhan Kabdylkakov, Victor Grishkov, A. A. Baturin |
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| Jazyk: | angličtina |
| Rok vydání: | 2019 |
| Předmět: |
Materials science
Hydrogen Thermal desorption spectroscopy Alloy thermal desorption spectroscopy chemistry.chemical_element Thermodynamics 02 engineering and technology engineering.material 01 natural sciences Article термодесорбционные исследования binary TiNi-based alloy Desorption бинарные сплавы 0103 physical sciences General Materials Science martensitic transformations 010302 applied physics мартенситные превращения водород 021001 nanoscience & nanotechnology Grain size Nanocrystalline material chemistry Martensite hydrogen engineering Grain boundary 0210 nano-technology удельное электросопротивление electrical resistivity |
| Zdroj: | Materials Volume 12 Issue 23 |
| Popis: | The analysis presented here shows that in B2-phase of Ti49.1Ni50.9 (at%) alloy, hydrogenation with further aging at room temperature decreases the temperatures of martensite transformations and then causes their suppression, due to hydrogen diffusion from the surface layer of specimens deep into its bulk. When hydrogen is charged, it first suppresses the transformations B2&harr B19&prime and R&harr in the surface layer, and when its distribution over the volume becomes uniform, such transformations are suppressed throughout the material. The kinetics of hydrogen redistribution is determined by the hydrogen diffusion coefficient DH, which depends on the grain size. In nanocrystalline Ti49.1Ni50.9 (at%) specimens, DH is three times greater than its value in coarse-grained ones, which is likely due to the larger free volume and larger contribution of hydrogen diffusion along grain boundaries in the nanocrystalline material. According to thermal desorption spectroscopy, two states of hydrogen atoms with low and high activation energies of desorption exist in freshly hydrogenated Ti49.1Ni50.9 (at%) alloy irrespective of the grain size. On aging at room temperature, the low-energy states disappear entirely. Estimates by the Kissinger method are presented for the binding energy of hydrogen in the two states, and the nature of these states in binary hydrogenated TiNi-based alloys is discussed. |
| Databáze: | OpenAIRE |
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