Orientational dependence of shape memory effects and superelasticity in CoNiGa, NiMnGa, CoNiAl, FeNiCoTi, and TiNi single crystals

Chumlyakov, Yu. I.; Киреева, И. В.; Караман, И.; Panchenko, E. Yu.; Zakharova, E. G.; Tverskov, A. V.; Ovsyannikov, A. A.; Nazarov, K. M.; Кириллов, В.В.

doi:10.1007/s11182-004-0001-1

Cited by 5 publications

(9 citation statements)

References 24 publications

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“…[12][13][14]20] So far, the magnetic field-controlled two-way shape-memory effect yielding a total strain of 4.5 pct, [21] the composition-dependent magnetization, and the transformation temperatures have been investigated, and structural and phase analysis were carried out. [12][13][14][22][23][24][25] In addition, the fundamental shapememory and PE properties as a function of temperature and stress such as the transformation strains, Clausius-Clapeyron relation, stress and thermal hysteresis, and the influence of deformation history on the transformation behavior were also addressed in several studies. [11,20,[23][24][25] However, the cyclic deformation and functional fatigue behavior, i.e., cyclic degradation of the functional properties, of CoNiGa alloys have not been addressed yet.…”

Section: Introductionmentioning

confidence: 99%

Pseudoelasticity and Cyclic Stability in Co49Ni21Ga30 Shape-Memory Alloy Single Crystals at Ambient Temperature

Dadda

Maier

Niklasch

et al. 2008

Metall Mater Trans A

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As-grown Co 49 Ni 21 Ga 30 [001]-and [123]-oriented single crystals were subjected to cyclic compression loading at room temperature above the austenite finish temperature of 15°C. Straincontrolled experiments were performed using both incremental strain steps and constant strain amplitudes. Cyclic deformation with a maximum strain amplitude of 2.5 pct resulted in rapid accumulation of irrecoverable strains in the [123]-oriented crystals. However, after a few cycles, the samples demonstrated cyclic stability with fully recoverable transformation. By contrast, the [001]-oriented crystals displayed excellent cyclic stability with hardly any change in stress-strain characteristics. In-situ optical microscopy and electron backscattered diffraction analysis were employed to clarify the events that take place at different stages of a typical loading-unloading history. The in-situ observations also revealed that the initiation and growth characteristics of stress-induced martensite (SIM) are heterogeneous on the microscopic scale in CoNiGa alloys. In addition, theoretical transformation and detwinning strains, and resolved shear stress factors (RSSFs), were calculated based on the energy minimization theory and are compared to the experimentally obtained orientation-dependent transformation stress and strain levels. It is shown that the selection of an appropriate orientation is one of the key criteria to optimize the pseudoelastic (PE) response and cyclic stability of CoNiGa alloys.

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Section: Introductionmentioning

confidence: 99%

Pseudoelasticity and Cyclic Stability in Co49Ni21Ga30 Shape-Memory Alloy Single Crystals at Ambient Temperature

Dadda

Maier

Niklasch

et al. 2008

Metall Mater Trans A

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“…In the case of precipitation of dispersed particle not undergoing any MT, additional elastic stresses Δσ i develop in the aged crystals due to elastic deformation of particles in the course of MT evolution [15]. In addition, there might be an increase in the surface energy needed for the generation of geometric defects in order to maintain consistency of the martensitic deformation of the matrix and elastic deformation of the particles during MT evolution in nanocomposites [14][15][16][17]. This gives rise to increased degree of overcooling ΔТ and, hence, a lower M s (the third term in Eq.…”

Section: Discussion Of Resultsmentioning

confidence: 99%

“…In this case, the fourth term in Eq. (1) can play a significant role and increase MT temperature, as shown in the aged Ti-Ni single crystals, whose particle size and interparticle spacing exceed 100 nm [14,17]. On the other hand, the particle size increased to d > 50 nm for the interparticle spacing L ≤ 50 nm in the investigated Co-Ni-Al crystals after their aging at the temperatures higher than 673 K (Group II) results in a total suppression of the B2-L1 0 MT.…”

Section: In Heterophase Crystals the Presence Of Local Internal Stresmentioning

confidence: 99%

Characteristic features of development of thermoelastic transformations in aged single crystals of a CoNiAl ferromagnetic alloy

et al. 2011

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Using Co 35 Ni 35 Al 30 (at. %) single crystals, the effect of temperature and duration of aging on the development of thermoelastic B2-L1 0 -martensitic transformations during heating/cooling is studied. It is found out that at room temperature these single crystals are in the В2-phase and contain a small volume fraction (about 2%) of the plastic γ-phase. In the aged single crystals, in the В2-matrix, Co-rich particles with hcp-and fcc-lattices and metastable Ni 2 Al particles precipitate, whose size is determined by the temperature and duration of aging. It is shown that aging gives rise decreased temperature of martensitic transformations. At the aging temperatures T ≥ 673 K there is a sharp increase in the temperature hysteresis and a total suppression of thermoelastic B2-L1 0 -martensitic transformations during heating/cooling and under loading. A thermodynamic description of the starting temperature of martensitic transformations M s as a function of microstructure of the aged single crystals particle size and interparticle spacing is proposed.

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“…On the other hand, in TiNi poly-and single crystals containing less than 51.0 at.% of Ni in the quenched and aged states at the axial stresses between 500-700 MPa the martensite achieves its yield strength, and superelasticity is accompanied by irreversible strains [1, 3,14,15]. Exceptions from the above are high-strength [001]-TiNi single crystals in compression with the content of Ni more than 51.5% [16].…”

Section: Methodsmentioning

confidence: 99%

“…Exceptions from the above are high-strength [001]-TiNi single crystals in compression with the content of Ni more than 51.5% [16]. In single-crystal CoNiAl and NiFeGa(Co) alloys, undergoing B2-L1 0 -transformations, high-temperature SE is observed up to 673 K, but the level of axial stresses strongly depends on orientation of these single crystals and they do not exceed 400 MPa in the single-phase state and 800 MPa in the aged [001]-single crystals of CoNiAl in compression [14,15,17,18]. Thus, heterophase Ti 48.5 Ni 51.5 and Ni 51.0 Ti 36.5 Hf 12.5 single crystals could be viewed as highstrength crystals with thermoelastic MTs.…”

Section: Methodsmentioning

confidence: 99%

Orientation Dependence of Functional Properties in Heterophase Single Crystals of the Ti36.5Ni51.0Hf12.5 and Ti48.5Ni51.5 Alloys

et al. 2016

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The features of orientation dependence of stress-induced thermoelastic B2-(R)-B19′-martensitic transformations in single crystals of the Ti 48.5 Ni 51.5 and Ni 51.0 Ti 36.5 Hf 12.5 (at.%) alloys, which contain disperse particles of the Ti 3 Ni 4 and H-phase, respectively, are revealed along with those of their shape-memory effects (SME) and superelasticity (SE). It is experimentally demonstrated that irrespective of the crystal structure of disperse particles measuring more than 100 nm, for their volume fraction f > 16% there is a weaker orientation dependence of the reversible strain in the cases of manifestation of SME and SE. In the orientations of Class I, wherein martensitic detwinning introduces a considerable contribution into transformation strain, the values of SME | SME | and SE | SE | decrease by over a factor of two compared to the theoretical lattice strain value | tr0 | for a B2-B19′-transformation and the experimental values of reversible strain for quenched TiNi crystals. In the orientations of Class 2, wherein detwinning of the martensite is suppressed as is the case in quenched single-phase single crystals, the reversible strain is maintained close to its theoretical value |ε tr0 |. Micromechanical models of interaction between the martensite and the disperse particles are proposed, which account for the weaker orientation dependence of | SME | and | SE | due to suppression of detwinning of the B19′-martensite crystals by the particles and a transition from a single-variant evolution of the stress-induced martensitic transformations to a multiple-variant evolution of transformations in the cases of increased size of the particles and their larger volume fractions.

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Orientational dependence of shape memory effects and superelasticity in CoNiGa, NiMnGa, CoNiAl, FeNiCoTi, and TiNi single crystals

Cited by 5 publications

References 24 publications

Pseudoelasticity and Cyclic Stability in Co49Ni21Ga30 Shape-Memory Alloy Single Crystals at Ambient Temperature

Pseudoelasticity and Cyclic Stability in Co49Ni21Ga30 Shape-Memory Alloy Single Crystals at Ambient Temperature

Characteristic features of development of thermoelastic transformations in aged single crystals of a CoNiAl ferromagnetic alloy

Orientation Dependence of Functional Properties in Heterophase Single Crystals of the Ti36.5Ni51.0Hf12.5 and Ti48.5Ni51.5 Alloys

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