Degradation of Functional Properties of Pseudoelastic NiTi Alloy Under Cyclic Loading: An Experimental Study

Iasnii, Volodymyr; Ясній, Петро Володимирович

doi:10.2478/ama-2019-0013

Cited by 13 publications

(4 citation statements)

References 30 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…For this purpose, we chose fracture surfaces of two specimens that were tested for different initial amplitudes of cyclic deformation ( Δε = 6.5 and 3.1%). These specimens failed after 773 and 2053 loading cycles, respectively [10,11], which corresponds to the conditions of low-cycle fatigue. In what follows, these specimens are denoted by A and B.…”

Section: Testing Methodsmentioning

confidence: 98%

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

et al. 2020

View full text Add to dashboard Cite

We study the macro-and microfractographic features of the mechanism of initiation and propagation of fatigue cracks in the nitinol alloy after its testing for low-cycle fatigue and analyze possible influence of the structural and phase transformations caused by the cyclic deformation of nitinol on the fractographic features of its fatigue fracture. Thus, almost parallel transcrystalline facets of brittle cleavage located in almost mutually perpendicular planes along the entire length of martensite crystals are observed within the boundaries of separate grains (first of all, in the early stages of fracture). The signs of shallow fatigue striations are detected (but rarely) in the zone of the stable growth of the fatigue crack. The spacing of these striations approximately corresponds to a crack-growth rate of 8 ⋅10 7 m/cycle. It is suggested that the deformation transformation of austenite into martensite can also distort the classical deformation mechanism of formation of the fatigue striations. In the zones of fractures with uncontrolled crack growth, the elements of ductile pit topography are predominant, which is typical of the fracture surfaces of specimens destroyed under active loading.

show abstract

Section: Testing Methodsmentioning

confidence: 98%

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

et al. 2020

View full text Add to dashboard Cite

show abstract

“…[1]). Недостатком данных сплавов является ухудшение в процессе многоцикловой эксплуатации их неупругих [2] и биохимических (коррозионной стойкости [3], биосовместимости [4]) свойств. Эти свойства зависят от состояния поверхности изделия и могут быть существенно улучшены путем модификации его поверхностного слоя [4] или синтеза защитных пленок или покрытий на его поверхности [3].…”

Section: Introductionunclassified

Поверхностный Ti-Ni-Ta-сплав, синтезированный на TiNi-подложке электронно-пучковым способом: структура и физико-механические свойства

Дьяченко¹,

Семин²,

Остапенко³

et al. 2023

Физика Твердого Тела

View full text Add to dashboard Cite

The structure and physical-mechanical properties of Ti-Ni-Ta-based surface alloy synthesized on the NiTi-substrate through additive thin-film electron-beam method have been studied. The synthesis of the surface alloy was carried out by 30-fold alternation of operations of deposition of a dopant film (Ti60Ta40 (at.%), ~50 nm thick) and liquid-phase mixing of the film/substrate using a pulsed low-energy high-current electron beam. It was found that Ti-Ni-Ta-based surface alloy, whose thickness is ~1.8 μm, has an amorphous structure. It has been established that the surface alloy has ~2 and ~1.5 times higher values of microhardness HOP and elastic modulus EOP compared to the initial NiTi-substrate, but parameter of plasticity δh and shape recovery ratio η close to the substrate. It is shown that the nature of the change in physical-mechanical properties in Ti-Ni-Ta-based surface alloy and the transition zone depends on the number and thickness of the sublayers, as well as on the structural states of the phases in the sublayers. The evaluation of the mechanical compatibility of the surface alloy with the NiTi-substrate is given.

show abstract

“…[1]). A downside of these alloys is degradation of their inelastic [2] and biochemical (corrosion resistance [3], biocompatibility [4]) properties in the process of multicycle operation. These properties depend on the condition of surface of the product and can be improved significantly by modifying its surface layer [4] or by synthesis of protective films or coatings on its surface [3].…”

Section: Introductionmentioning

confidence: 99%

Ti-Ni-Ta-based surface alloy synthesized on the TiNi-substrate through electron-beam method: structure and physical-mechanical properties

D'yachenko

Semin

Ostapenko

et al. 2023

Physics of the Solid State

View full text Add to dashboard Cite

The structure and physical-mechanical properties of Ti-Ni-Ta-based surface alloy synthesized on the TiNi-substrate through additive thin-film electron-beam method have been studied. The synthesis of the surface alloy was carried out by 30-fold alternation of operations of deposition of a dopant film (Ti60Ta40 (at.%), ~50 nm thick) and liquid-phase mixing of the film/substrate using a pulsed low-energy high-current electron beam. It was found that Ti-Ni-Ta-based surface alloy, whose thickness is ~1.8 μm, has an amorphous structure. It has been established that the surface alloy has ~2 and ~1.5 times higher values of microhardness HOP and elastic modulus EOP compared to the initial TiNi-substrate, but parameter of plasticity deltah and shape recovery ratio eta close to the substrate. It is shown that the nature of the change in physical-mechanical properties in Ti-Ni-Ta-based surface alloy and the transition zone depends on the number and thickness of the sublayers, as well as on the structural states of the phases in the sublayers. The evaluation of the mechanical compatibility of the surface alloy with the TiNi-substrate is given. Keywords: Ti-Ni-Ta-based surface alloy, nickel titanium alloy, thin films, additive thin-film electron-beam synthesis, structure, physical-mechanical properties, strength and ductility parameters.

show abstract

Degradation of Functional Properties of Pseudoelastic NiTi Alloy Under Cyclic Loading: An Experimental Study

Cited by 13 publications

References 30 publications

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

Fractographic Features of the Fatigue Fracture of Nitinol Alloy

Поверхностный Ti-Ni-Ta-сплав, синтезированный на TiNi-подложке электронно-пучковым способом: структура и физико-механические свойства

Ti-Ni-Ta-based surface alloy synthesized on the TiNi-substrate through electron-beam method: structure and physical-mechanical properties

Contact Info

Product

Resources

About