scholarly journals Shape Memory Effect and Superelasticity of [001]-Oriented FeNiCoAlNb Single Crystals Aged under and without Stress

Metals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 943
Author(s):  
Yuriy I. Chumlyakov ◽  
Irina V. Kireeva ◽  
Zinaida V. Pobedennaya ◽  
Philipp Krooß ◽  
Thomas Niendorf
Keyword(s):  
Energy Dissipation ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Single Crystals ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermoelastic Martensitic Transformation ◽  
Β Phase ◽  
High Level ◽  
Hardening Coefficient

The two-step ageing of Fe-28Ni-17Co-11.5Al-2.5Nb (at. %) single crystals under and without stress, leads to the precipitation of the γ′- and β-phase particles. Research has shown that γ–α′ thermoelastic martensitic transformation (MT), with shape memory effect (SME) and superelasticity (SE), develops in the [001]-oriented crystals under tension. SE was observed within the range from the temperature of the start of MT upon cooling Ms, to the temperature of the end of the reverse MT upon heating Af, and at temperatures from Af to 323–373 K. It was found that at γ–α′ MT in the [001]-oriented crystals, with γ′- and β-phase particles, a high level of elastic energy, ΔGel, is generated, which significantly exceeds the energy dissipation, ΔGdis. As a result, the temperature of the start of the reverse MT, while heating As, became lower than the temperature Ms. The development of γ–α′ MT under stress occurs with high values of the transformation hardening coefficient, Θ = dσ/dε from 2 to 8 GPa and low values of mechanical Δσ and thermal ΔTh hysteresis. The reasons for an increase in ΔGel during the development of γ–α′ MT under stress are discussed.

scholarly journals Влияние режима старения в мартенситном состоянии под сжимающей нагрузкой на двусторонний эффект памяти формы в монокристаллах ферромагнитного сплава Ni-=SUB=-49-=/SUB=-Fe-=SUB=-18-=/SUB=-Ga-=SUB=-27-=/SUB=-Co-=SUB=-6-=/SUB=-

2020 ◽  
Vol 46 (12) ◽  
pp. 51
Author(s):  
А.Б. Тохметова ◽  
Н.Г. Ларченкова ◽  
Е.Ю. Панченко ◽  
Ю.И. Чумляков
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Single Crystals ◽  
Compressive Stress ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Work Output ◽  
Thermoelastic Martensitic Transformation ◽  
Maximum Work ◽  
Maximum Work Output

The effects of stress-induced martensite aging (SIM-aging) along the [110]B2-direction on the thermoelastic martensitic transformation in Ni49Fe18Ga27Co6 single crystals were investigated. It was experimentally established that the effective regime of SIM-aging (at T = 423 K, 1 h under a compressive stress 450 MPa) results in a stabilization of stress-induced martensite and inducing the tensile two-way shape memory effect with reversible strain of +9.0 (± 0.3) % along the [001]B2-direction which is the perpendicular to the SIM-aging axis. Maximum work output of Wmax = 0.14 J/g (1125 kJ/m3) that can be realized using the two-way shape memory effect was obtained.

Shape memory effect due to magnetic field-induced thermoelastic martensitic transformation in polycrystalline Ni–Mn–Fe–Ga alloy

2001 ◽  
Vol 291 (2-3) ◽  
pp. 175-183 ◽  
Author(s):  
A.A. Cherechukin ◽  
I.E. Dikshtein ◽  
D.I. Ermakov ◽  
A.V. Glebov ◽  
V.V. Koledov ◽  
...  
Keyword(s):  
Magnetic Field ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermoelastic Martensitic Transformation

High-temperature shape memory effect and the B2-L10 thermoelastic martensitic transformation in Ni-Mn intermetallics

2013 ◽  
Vol 58 (6) ◽  
pp. 878-887 ◽  
Author(s):  
V. G. Pushin ◽  
N. N. Kuranova ◽  
E. B. Marchenkova ◽  
E. S. Belosludtseva ◽  
V. A. Kazantsev ◽  
...  
Keyword(s):  
High Temperature ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermoelastic Martensitic Transformation

Martensitic Transformation and Microstructural Characteristics in Copper Based Shape Memory Alloys

2012 ◽  
Vol 510-511 ◽  
pp. 105-110 ◽  
Author(s):  
Osman Adiguzel
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Martensitic Transformations ◽  
Microstructural Characteristics ◽  
Shape Memory Property ◽  
Martensite Variant ◽  
Cooperative Movement ◽  
Β Phase

Martensitic transformations are first order solid state phase transitions and occur in the materials on cooling from high temperature. Shape memory effect is an unusual property exhibited by certain alloy systems, and based on martensitic transformation. The shape memory property is characterized by the recoverability of previously defined shape or dimension when they are subjected to variation of temperature. The shape memory effect is facilitated by martensitic transformation, and shape memory properties are intimately related to the microstructures of the materials. Martensitic transformations occur as martensite variant with the cooperative movement of atoms on {110}β - type plane of austenite matrix. Martensitic transformations have diffusionless character, and the atomic movement is confined to interatomic lengths in the materials. The basic factors which govern the martensitic transformation are Bain distortion and homogeneous shears. Copper based alloys exhibit this property in metastable β-phase field.

Phase Transitions and Elementary Processes in Shape Memory Alloys

2015 ◽  
Vol 1101 ◽  
pp. 124-128
Author(s):  
Osman Adiguzel
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Smart Materials ◽  
Structural Changes ◽  
Elementary Processes ◽  
Cooperative Movement ◽  
Β Phase

Shape memory effect is a peculiar property exhibited by certain alloy systems, and shape memory alloys are recognized to be smart materials. These alloys have important ability to recover the original shape of material after deformation, and they are used as shape memory elements in devices due to this property. The shape memory effect is facilitated by a displacive transformation known as martensitic transformation. Shape memory effect refers to the shape recovery of materials resulting from martensite to austenite transformation when heated above reverse transformation temperature after deforming in the martensitic phase. These alloys also cycle between two certain shapes with changing temperature.Martensitic transformations occur with cooperative movement of atoms by means of lattice invariant shears on a {110} - type plane of austenite matrix which is basal plane of martensite.Copper based alloys exhibit this property in metastable β-phase field. High temperature β-phase bcc-structures martensiticaly undergo the non-conventional structures following two ordered reactions on cooling, and structural changes in nanoscale level govern this transition cooling. Atomic movements are also confined to interatomic lengths due to the diffusionless character of martensitic transformation.

TRANSFORMATION BEHAVIOR AND SHAPE MEMORY EFFECT OF A CoAl ALLOY

2009 ◽  
Vol 23 (06n07) ◽  
pp. 1931-1936 ◽  
Author(s):  
FENG CHEN ◽  
BING TIAN ◽  
YUXIANG TONG ◽  
YUFENG ZHENG
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Strain Curve ◽  
Bending Test ◽  
Al Alloy ◽  
Sem Images ◽  
Β Phase ◽  
Fcc Phase

This paper investigates the microstructure, martensitic transformation and shape memory effect of Co -16 Al alloy. The optical micrographs of Co -16 at .% Al alloy quenched from 1200°C show that the ε martensite occurs at room temperature, while some remaining γ phase can also be observed. This microstructure analysis can be supported by XRD pattern. It is shown that the alloy undergoes a martensitic reverse transformation at about 220°C during heating. However, no transformation from the fcc phase to hcp phase is detected by DSC measurement upon cooling. It is thought that the precipitation of β phase by aging at high temperature may suppress the martensitic transformation. The tension strain is 12% and the fracture strength is above 800MPa. No obvious yield deformation is observed from the stress-strain curve. SEM images exhibits many dimples on the fracture surface, which means the fracture mechanism is ductile rupture. Bending test show that only 25% deformation can be recovered due to shape memory effect when the pre-strain is 5%.

Shape Memory Effect and Superelasticity in Single Crystals of High-Strength Ferromagnetic Alloys

2014 ◽  
Vol 1013 ◽  
pp. 15-22 ◽  
Author(s):  
Yuri Chumlyakov ◽  
Irina Kireeva ◽  
Elena Panchenko ◽  
Ekaterina Timofeeva ◽  
Irina Kretinina ◽  
...  
Keyword(s):  
Chemical Composition ◽  
Martensitic Transformation ◽  
Shape Memory ◽  
Single Crystals ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Functional Properties ◽  
Volume Fraction ◽  
High Strength ◽  
Ferromagnetic Alloys

In the present study the effect of second γ'-phase particles which do not undergo martensitic transformation on the functional properties – shape memory effect and superelasticity, in ferromagnetic FeNiCoAlX (X = Ta, Nb, Ti) and NiFeGaCo single crystals are investigated. Dispersed γ'-phase particles allow to control both mechanical and functional properties due to variation of chemical composition, volume fraction and size of nanoparticles, and to obtain the nanocomposites with complex of necessary properties.

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