Shape Memory Behavior of Rapidly Quenched High-copper TiNiCu Alloys

Shelyakov, A. V.; Sitnikov, Nikolay; Khabibullina, I. A.; Borodako, Kirill; Sevryukov, O. N.

doi:10.24840/2183-6493_007.002_0002

Cited by 2 publications

(2 citation statements)

References 14 publications

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“…Promising materials that meet the above requirements are quasibinary intermetallic TiNi-TiCu system alloys rapidly quenched from the liquid state in the form of thin 20-50 µm ribbons [6,7]. At high cooling rates (about 10 6 • C/s), this method allows for the production of high-copper (more than 20 at.%) amorphous alloys which exhibit excellent performance and a narrow temperature hysteresis of the SME after crystallization [8][9][10][11][12][13][14]. Their properties largely depend on the structure of the initial amorphous material.…”

Section: Introductionmentioning

confidence: 99%

Study of Structure and Phase Transformations in Rejuvenated Rapidly Quenched TiNiCu Alloys

Shelyakov

Sitnikov

Zaletova³

et al. 2023

Metals

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Alloys of the quasibinary TiNi-TiCu system manufactured by melt quenching in the form of thin 20–50 μm ribbons have proven to show good potential as materials for the fabrication of micromechanical devices. At high cooling rates (about 106 K/s), this method allows producing high-copper (more than 20 at.%) amorphous alloys which exhibit an excellent shape-memory effect after crystallization. Their properties are known to largely depend on the crystallization conditions and the structure of the initial amorphous material acting as a precursor for the formation of crystal phases. It has been shown recently that the rejuvenation procedure (cryogenic thermocycling) of metallic glasses is one of the most promising methods of improving their properties. In this study, we investigated for the first time the effect of cryogenic thermocycling of rapidly quenched amorphous TiNiCu on the initial state, as well as on structure formation and the phase transformation patternsof subsequent crystallization conducted using various methods. The effect was analyzed utilizing the methods of scanning and transmission electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry. The results show that rejuvenation treatment slightly reduces the glass transition and crystallization onset temperatures and moderately changes the sizes of structural features (grains, martensite plates), the quantity of the martensite phase, and the characteristic temperatures and enthalpy of the martensitic transformation.

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Section: Introductionmentioning

confidence: 99%

Study of Structure and Phase Transformations in Rejuvenated Rapidly Quenched TiNiCu Alloys

Shelyakov

Sitnikov

Zaletova³

et al. 2023

Metals

Self Cite

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“…This problem can be solved Metals 2021, 11, 1528 2 of 15 using the technology of rapid quenching from liquid state which allows obtaining TiNi-TiCu system alloys with a high Cu content in the form of thin ribbons with a single-phase composition and a homogeneous structure [16,17]. At high cooling rates (10 6 K/s or higher) this technique allows producing amorphous ribbons of 30-50 µm in thickness [18,19] which exhibit the best SME performance after crystallization [19][20][21]. The conditions of quenching from melt have a strong effect on the structure of the amorphous state as the precursor of crystalline phase formation.…”

Section: Introductionmentioning

confidence: 99%

Effect of External Impacts on the Structure and Martensitic Transformation of Rapidly Quenched TiNiCu Alloys

Shelyakov

Sitnikov

Zaletova

et al. 2021

Metals

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TiNi-TiCu quasibinary system alloys with a high Cu content produced by rapid quenching from liquid state in the form of thin amorphous ribbons exhibit pronounced shape memory effect after crystallization and are promising materials for miniaturized and fast operating devices. There is currently no complete clarity of the mechanisms of structure formation during crystallization from the amorphous state that determine the structure-sensitive properties of these alloys. This work deals with the effect of the initial amorphous state structure and crystallization method of the alloys on their structure and phase transformations. To this end the alloy containing 30 at.% Cu was subjected to thermal and mechanical impact in the amorphous state and crystallized using isothermal or electropulse treatment. We show that after all types of treatment in the amorphous state the structure of the alloy remains almost completely amorphous but the characteristic temperatures and enthalpy of crystallization become slightly lower. Isothermal crystallization of alloy specimens produces a submicrocrystalline structure with an average grain size in the 0.4–1.0 μm range whereas electropulse crystallization generates a bimorphic structure consisting of large 4–6 μm grains and 2–3 μm high columnar crystals in the vicinity of the surface. The grains have nanosized plate-like and subgrain structures. The largest grains are observed in thermally activated samples, meanwhile, mechanical impact in the amorphous state leads to the formation of equiaxed finer grains with a less defective subgrain structure and to the shift of the temperature range of the martensitic transformation toward lower temperatures.

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Shape Memory Behavior of Rapidly Quenched High-copper TiNiCu Alloys

Cited by 2 publications

References 14 publications

Study of Structure and Phase Transformations in Rejuvenated Rapidly Quenched TiNiCu Alloys

Study of Structure and Phase Transformations in Rejuvenated Rapidly Quenched TiNiCu Alloys

Effect of External Impacts on the Structure and Martensitic Transformation of Rapidly Quenched TiNiCu Alloys

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