Two-way shape memory effect developed by martensite deformation in NiTi

Liu, Yinong; Liu, Yong; Humbeeck, Jan Van

doi:10.1016/s1359-6454(98)00325-5

Cited by 228 publications

(154 citation statements)

References 16 publications

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“…Another functional property exhibited by these materials is the two-way shape memory effect [4]. When the material is trained to have this property, it "remembers" a given geometrical shape in the parent phase and another in the martensitic phase.…”

Section: Figmentioning

confidence: 99%

“…As a requirement for the two-way shape memory effect, after each load/unload cycle the material must be heated above the A ?f temperature so that martensite transforms into austenite [4]. Thus, Falvo et al [130] recorded (i) the residual strain, ε ?r , corresponding to the strain at 0 stress after each load/unload cycle, (ii) the recovery deformation, ε ?re , which corresponded to the strain at 0 stress after transformation into austenite and (iii) the two-way shape memory strain ε ?tw , after subsequent cooling to the martensitic phase.…”

Section: Shape Memory Effectmentioning

confidence: 99%

“…An assembly of martensitic variants may exist in two distinct forms: twinned martensite or detwinned martensite. The former is created by the combination of self-accommodated martensitic variants to keep the overall shape when martensite is thermally induced, while in the latter a specific variant is dominant in the system, usually as a result of an applied external load [4].…”

Section: Introductionmentioning

confidence: 99%

See 2 more Smart Citations

Welding and Joining of NiTi Shape Memory Alloys: A Review

Oliveira

Miranda

Fernandes

2017

Progress in Materials Science

255

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Section: Figmentioning

confidence: 99%

Section: Shape Memory Effectmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Welding and Joining of NiTi Shape Memory Alloys: A Review

Oliveira

Miranda

Fernandes

2017

Progress in Materials Science

255

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“…There is no twin relation between neighboring martensite variants after compression because of the generation and movement of lattice defects. [43][44][45][46] The mechanical behaviors are nearly the same before the plastic deformation of reoriented martensite under quasi-static compression and dynamic compression, and the plastic stress level under dynamic loading is 500 MPa higher than that under quasi-static compression. [47] NiTi SMAs also exhibit a dynamic sensitivity.…”

Section: Introductionmentioning

confidence: 93%

Influence of Dynamic Compression on Phase Transformation of Martensitic NiTi Shape Memory Alloys

Qiu

Young

Nie

2015

Metall Mater Trans A

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Shape memory alloys (SMAs) exhibit high damping capacity in both austenitic and martensitic phases, due to either a stress-induced martensite phase transformation or a stress-induced martensite variant reorientation, making them ideal candidates for vibration suppression devices to protect structural components from damage due to external forces. In this study, both quasi-static and dynamic compression was conducted on a martensitic NiTi SMA using a mechanical loading frame and on a Kolsky compression bar, respectively, to examine the relationship between microstructure and phase transformation characteristics of martensitic NiTi SMAs. Both endothermic and exothermic peaks disappear completely after experiencing deformation at a strain rate of 10 3 s À1 and to a strain of about 10 pct. The phase transformation peaks reappear after the deformed specimens were annealed at 873 K (600°C) for 30 minutes. As compared to samples from quasi-static loading, where a large amount of twinning is observed with a small amount of grain distortion and fracture, samples from dynamic loading show much less twinning with a larger amount of grain distortion and fracture.

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“…3 Some of these training procedures consist of constant load thermal cycling (e.g., in NiTi, [4][5][6][7] NiTiPd, 7,8 CuZnAl, 9,10 and TiNiNb 11 ), martensite deformation and free/constrained recovery (e.g., in tension, [12][13][14] compression, 15 and bending [16][17][18][19] ), deformation cycling of austenite to promote the stress-induced martensitic transformation, [20][21][22] or precipitation during constrained aging. [23][24][25][26] The principle behind all these training methods involves the formation of internal stress fields that induce the same martensite variants during transformation as were generated during training, but without the need for external stress.…”

Section: Introductionmentioning

confidence: 99%

Role of B19′ martensite deformation in stabilizing two-way shape memory behavior in NiTi

Benafan

Padula

Noebe

et al. 2012

Journal of Applied Physics

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Deformation of a B19′ martensitic, polycrystalline Ni49.9Ti50.1 (at. %) shape memory alloy and its influence on the magnitude and stability of the ensuing two-way shape memory effect (TWSME) was investigated by combined ex situ mechanical experimentation and in situ neutron diffraction measurements at stress and temperature. The microstructural changes (texture, lattice strains, and phase fractions) during room-temperature deformation and subsequent thermal cycling were captured and compared to the bulk macroscopic response of the alloy. With increasing uniaxial strain, it was observed that B19′ martensite deformed by reorientation and detwinning with preferred selection of the (1¯50)M and (010)M variants, (201¯)B19′ deformation twinning, and dislocation activity. These mechanisms were indicated by changes in bulk texture from the neutron diffraction measurements. Partial reversibility of the reoriented variants and deformation twins was also captured upon load removal and thermal cycling, which after isothermal deformation to strains between 6% and 22% resulted in a strong TWSME. Consequently, TWSME functional parameters including TWSME strain, strain reduction, and transformation temperatures were characterized and it was found that prior martensite deformation to 14% strain provided the optimum condition for the TWSME, resulting in a stable two-way shape memory strain of 2.2%. Thus, isothermal deformation of martensite was found to be a quick and efficient method for creating a strong and stable TWSME in Ni49.9Ti50.1.

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Two-way shape memory effect developed by martensite deformation in NiTi

Cited by 228 publications

References 16 publications

Welding and Joining of NiTi Shape Memory Alloys: A Review

Welding and Joining of NiTi Shape Memory Alloys: A Review

Influence of Dynamic Compression on Phase Transformation of Martensitic NiTi Shape Memory Alloys

Role of B19′ martensite deformation in stabilizing two-way shape memory behavior in NiTi

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