Effect of Grain Size and Ageing-Induced Microstructure on Functional Characteristics of a Ti-50.7 at.% Ni Alloy

Polyakova, K. A.; Рыклина, Е. П.; Прокошкин, С. Д.

doi:10.1007/s40830-020-00269-z

Cited by 18 publications

(4 citation statements)

References 25 publications

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“…The scope of their clinical use in surgery is extremely wide, including various manipulators, cava filters, septal occlusion devices, vascular stents and stents for tubular structures, prostheses (osseous, ligamental, dental), compressive devices, and implants [1][2][3]. The traditional processing of NiTi alloys includes a thermomechanical treatment as well as subsequent post-deformation annealing (PDA) [3][4][5]; varying the aging modes makes it possible to precisely control aging-induced microstructure, transformation, and functional response over a wide temperature range [6][7][8][9].…”

Section: Introductionmentioning

confidence: 99%

“…The cited publications, however, do not provide an exhaustive knowledge of the structural responses of Young's modulus, since the comparative tests in the above cited studies are restricted by one or two kinds of structures (mainly recrystallized [15,17] or as-deformed [16,18]). Meanwhile, post-deformation annealing (PDA) is an obligatory procedure to provide a necessary temperature range for the shape recovery as well as other functional characteristics [3][4][5][6][7][8][9]19].…”

Section: Introductionmentioning

confidence: 99%

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On Structural Sensitivity of Young’s Modulus of Ni-Rich Ti-Ni Alloy

Рыклина

Murygin

Komarov

et al. 2023

Metals

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When developing bone implants, Young’s modulus is one of the primary characteristics of the material that should be considered. This study focuses on regulating the modulus of Ti-50.8 at.% Ni alloy by varying the grain/subgrain size as well as the initial structure using subsequent aging at 430 °C for 10 h. After post-deformation annealing (PDA), the temperature dependence of Young’s modulus exhibits a pronounced V-shaped character with a minimum at the onset temperature of the forward martensitic transformation, Ms, regardless of the structure. The grain/subgrain size of B2-austenite strongly affects the modulus magnitude. This effect is ambiguous for a material with a grain size range of 0.13–3 µm and depends on the test temperature. The effect of aging on the modulus reduction depends on the initial structure; it is most pronounced in an alloy with a relatively coarse grain size of 9 µm and brings a decrease of 3.8 times at a temperature of 37 °C. Aging of the initially recrystallized Ni-rich NiTi alloy makes it possible to obtain a вone-like elastic modulus of E = 12–13 GPa at an operating temperature of 37 °C. An ultrafine-grained substructure exhibits the same Young’s modulus values in the low temperature range from −100 to 25 °C.

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Section: Introductionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

On Structural Sensitivity of Young’s Modulus of Ni-Rich Ti-Ni Alloy

Рыклина

Murygin

Komarov

et al. 2023

Metals

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“…Известно, что размер зерна исходной фазы (B2-аустенита) влияет на функциональные и механические свойства СПФ Ti-Ni [10][11][12][13][14][15][16][17][18]. В работе [12] было показано, что в сплаве Ti-50,8ат.%Ni после холодного волочения с обжатием 25 % и отжига при t = 700 °С с выдержкой от 3 мин до 24 ч температура начала мартенситного превращения практически не изменяется в результате увеличения размера зерна от 5 до 22 мкм, а дополнительное старение при t = 250 °С, τ = 24 ч меняет стадийность мартенситных превращений.…”

Section: Introductionunclassified

“…В работе [12] было показано, что в сплаве Ti-50,8ат.%Ni после холодного волочения с обжатием 25 % и отжига при t = 700 °С с выдержкой от 3 мин до 24 ч температура начала мартенситного превращения практически не изменяется в результате увеличения размера зерна от 5 до 22 мкм, а дополнительное старение при t = 250 °С, τ = 24 ч меняет стадийность мартенситных превращений. В то же время авторами [13,14] выявлено, что исходный размер рекристаллизованного зерна в диапазоне 5-15 мкм влияет на распределение частиц фазы Ti 3 Ni 4 , кинетику мартенситных превращений, а также функциональные свойства СПФ Ti-50,7ат.%Ni.…”

Section: Introductionunclassified

Effect of annealing temperature and time on martensitic transformation temperatures and mechanical properties of the Ti–50.7at.%Ni shape memory alloy

Полякова¹,

Komarov²

2021

Izv.VUZ. Tsvet. Met.

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The study covers the effect of recrystallization annealing temperature and time on the characteristic temperatures of martensitic transformations and mechanical properties of the Ti–50.7at.%Ni shape memory alloy in the form of wire after cold drawing at room temperature. Six modes of post-deformation annealing with different temperatures and holding times were studied for the alloy to obtain structures with different sizes of recrystallized grains. The recrystallized grain size was determined by electron backscatter diffraction (EBSD). It was shown that the size of recrystallized grains increases from 2.5 to 9 μm, with both an increase in the annealing temperature (600– 700 °С) and an increase in the holding time (0.5–5.0 h). The characteristic temperatures of direct and reverse martensitic transformations were determined using differential scanning calorimetry. It was shown that the threefold growth of the recrystallized grain size reduces the starting temperature of the direct martensitic transformation, and extends the temperature range of the reverse martensitic transformation. The results of mechanical tests (stretching tests) at room temperature showed that an increase in the grain size leads to a decrease in the dislocation yield strength and an increase in the phase yield strength. It was established that the dislocation yield strength obeys the Hall–Petch law, and the phase yield strength is determined by the test temperature position relative to the starting (or peak) temperature of the direct martensitic transformation. Heat treatment modes for specific products should be recommended taking into account these two competing factors, as well as reverse martensitic transformation temperatures determining the alloy strain recovery temperatures.

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