Specifics of Crystallization of Amorphous TiNiCu Alloys with High Concentrations of Copper

Shelyakov, A. V.; Sitnikov, Nikolay; Khabibullina, I. A.; Сундеев, Р.В.; Sevryukov, O. N.

doi:10.1134/s1063783420060281

Cited by 10 publications

(12 citation statements)

References 12 publications

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“…which is in agreement with earlier data [22,23,27]. One can however note that the intensity of the B19 phase reflections in the diffraction patterns of the dynamically crystallized specimens both in the initial and in the activated amorphous states is slightly higher as compared with that of the isothermally crystallized specimens (Figure 6).…”

Section: Resultssupporting

confidence: 92%

“…X-ray study of the specimen structure showed that all the specimens after isothermal and electropulse crystallization have the B19 martensitic structure at room temperature which is in agreement with earlier data [22,23,27]. One can however note that the intensity of the B19 phase reflections in the diffraction patterns of the dynamically crystallized specimens both in the initial and in the activated amorphous states is slightly higher as compared with that of the isothermally crystallized specimens (Figure 6).…”

Section: Resultssupporting

confidence: 90%

“…Then we studied the effect of the amorphous state "activated" by the thermal and mechanical treatment on the crystalline structure formed by two methods: isothermal annealing at 500 • C for 300 s [22,23] and electropulsing with passing a single electric current pulse with preset duration of 10 ms [27]. It is well known that the crystallization of an amorphous state is a complex process accompanied by competing mechanisms of the nucleation and growth of various crystalline phases under permanently changing conditions of the chemical environment of atoms in transformation regions [30].…”

Section: Discussionmentioning

confidence: 99%

“…It has been shown that an increase in the quenching rate increases the degree of amorphization, i.e., the degree of disorder, thus favoring a significant reduction in the dimensions of the crystallization products given the same morphology and crystalline structure of the material [22]. An increase in the copper content leads to an increase in the amorphization ability of the alloys and hence an improvement of the stability of ribbon geometrical parameters [17,23] but also a reduction of the plasticity of the alloys and their SME parameters after isothermal treatment due to the formation of brittle Ti-Cu phases [19,23,24]. In the meantime many studies have shown that the phase composition, morphology and average grain size of TiNi-TiCu system alloys with a high copper content that were crystallized from the amorphous state depend strongly on the crystallization conditions.…”

Section: Introductionmentioning

confidence: 99%

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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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Section: Resultssupporting

confidence: 92%

Section: Resultssupporting

confidence: 90%

Section: Discussionmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

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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“…Generally, the irradiated layer has three distinct completely different phase transformations zone: melting zone; zone of quenching from a solid state; transitional or heat-affected zone, formed by heating the basic metal due to heat remove from the irradiated spot. Laser treatment of metals with surface melting opens up new opportunities for obtaining a qualitatively different structural state in alloys compared to traditional processes of thermal hardening with concentrated energy flows [4][5][6][7].…”

Section: Discussion Of Resultsmentioning

confidence: 99%

Dynamic Nanostructuring of the Steel Surface Under High-Speed Thermal Heating

Brover

Moysova

et al. 2020

MATEC Web Conf.

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Structure and functional properties of rapidly quenched TiNiCu alloys with high copper contents

Shelyakov

Sitnikov

Borodako

et al. 2021

J. Phys.: Conf. Ser.

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Thin materials exhibiting the shape memory effect, with a narrow temperature hysteresis, are required to create miniature and high-speed devices. Quasi-binary intermetallic TiNi-TiCu alloys with high copper contents (more than 10 at %) demonstrate the reversible martensitic transformation with a small (4-6 K) hysteresis. Alloys of the TiNi–TiCu system with a copper content of 30–40 at.% were fabricated in an amorphous state by the planar flow casting technique at a melt cooling rate of 106 K/s in the form of ribbons 30–50 μm thick. The alloy samples were subjected to dynamic crystallization using a single electric current pulse with duration of 5 ms. X-ray diffraction studies revealed almost fully martensitic state of the alloys with B19 structure at room temperature. TEM examination showed their structure to contain typical B19-martensite plates with a mean size of 20–80 nm. At the same time, the alloys exhibit a one-stage phase martensitic transformation B2↔B19 in the temperature range of (55÷75)°C, as well as pronounced shape memory effect, whose properties are largely determined by the structural parameters of the alloys.

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Specifics of Crystallization of Amorphous TiNiCu Alloys with High Concentrations of Copper

Cited by 10 publications

References 12 publications

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

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

Dynamic Nanostructuring of the Steel Surface Under High-Speed Thermal Heating

Structure and functional properties of rapidly quenched TiNiCu alloys with high copper contents

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