Physical nature of martensite transformations in B2-type Ti compounds and TiNi-based alloys

Лотков, А. И.; Батурин, А. А.

doi:10.1016/j.physme.2011.12.005

Cited by 8 publications

(2 citation statements)

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“…After long-term aging at room temperature, the ρ(T) dependences of the hydrogenated specimens reveal only a B2→R transformation and premartensite effects: An increase in ρ without its steep decrease characteristic of R→B19′ and B2→B19′ [24]. Increasing the aging time greatly decreases the hysteresis of the ρ(T) dependences of hydrogenated Ti 49.1 Ni 50.9 on cooling and heating in the temperature range of martensite transformations (Figure 1).…”

Section: Resultsmentioning

confidence: 99%

“…However, when applied to medical products (e.g., implants and dental devices, which are in long-term contact with hydrogen-containing saline and human tissue,), alloys such as these reveal hydrogen embrittlement and influence of absorbed hydrogen on their martensite transformations and functional properties—in particular, SME and SE [2,3,4]. It is this problem that stimulates the research in the interaction of hydrogen with near-equiatomic TiNi [5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24,25,26,27,28,29,30,31,32,33,34,35].…”

Section: Introductionmentioning

confidence: 99%

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The Effect of Hydrogen on Martensite Transformations and the State of Hydrogen Atoms in Binary TiNi-Based Alloy with Different Grain Sizes

et al. 2019

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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↔B19′ and R↔B19′ 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.

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Section: Resultsmentioning

confidence: 99%