Functional Properties of TiNi Shape Memory Alloy after High Strain Rate Loading

Bragov, A. M.; Galieva, Alesia; Grigorieva, Viktoria; Danilov, A.; Konstantinov, A. Y.; Lomunov, A. K.; Motorin, Yuri; Ostropiko, Eugeny; Razov, A. I.

doi:10.4028/www.scientific.net/msf.738-739.326

Cited by 14 publications

(16 citation statements)

References 12 publications

(13 reference statements)

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“…However, understanding of the main laws and structural mechanisms of high strain rate deforma tion of these materials remains incomplete without studying their mechanical response to high strain rate tension. The progress achieved in recent years in the modification of the equipment used to perform dynamic tensile tests made it possible to carry out investigations (although insufficient so far) of the mechanical behavior of these alloys under conditions of high strain rate tension [10][11][12][13]. The interest in dynamic extension is mainly related to the instability of the development of deformation, which manifests itself in the formation and propagation of zones (bands) of localized deformation observed upon the tension of polycrystalline NiTi alloys at small rates in both the austenitic and martensitic states [14][15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

Mechanical and structural aspects of high-strain-rate deformation of NiTi alloy

Bragov

Danilov

Konstantinov

et al. 2015

Phys. Metals Metallogr.

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The mechanical behavior of the binary polycrystalline NiTi alloy with a quasi equilibrium struc ture has been considered in the course of the high strain rate extension in a temperature range of 20-300°C. The quasi equilibrium structure, which is necessary to ensure the long term stability of special properties of the alloy, was achieved using aging, after which both the forward and reverse martensitic transformations exhibited a multistage character and the phase composition at room temperature was characterized by the presence of R and B19' martensites. To separate the contributions that come from the equilibrium structure and from the high rate of tension to the mechanical behavior of the alloy, a comparative analysis of the dia grams of high strain rate and quasi static tension has been performed. It has been shown that the action of several mechanisms of reversible deformation is determined by the specific features of the equilibrium struc ture, and the level of stresses at which these mechanisms are developed is controlled by the rate of tension. The results of the X ray diffraction study of the phase composition of the alloy samples after high strain rate tension, which make it possible to conclude that the mechanical behavior of martensite and austenite upon the dynamic tension of the alloy is determined by the development of stress induced R → B19', B2 → R, and B2 → B19' transformations and by the processes of the detwinning and reorientation of crystals of B19' mar tensite, are given.

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Section: Introductionmentioning

confidence: 99%

Mechanical and structural aspects of high-strain-rate deformation of NiTi alloy

Bragov

Danilov

Konstantinov

et al. 2015

Phys. Metals Metallogr.

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“…Millett et al [26] examined the shock behavior of NiTi SMAs during one-dimensional shock loading at impact velocities of 200-875 ms -1 . The influence of high strain rate on the functional properties (e.g., two-way shape memory effect) of NiTi SMAs was conducted by Bragov et al [27]. With a digital image correlation technique, the strain field of NiTi SMAs was measured by Saletti et al [28] under moderate strain rate.…”

Section: Introductionmentioning

confidence: 99%

High Strain Rate Compression of Martensitic NiTi Shape Memory Alloys

Qiu

Young

Nie

2015

Shap. Mem. Superelasticity

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The compressive response of martensitic NiTi shape memory alloys (SMAs) under high strain rate (1200 s -1 ) was investigated on a modified Kolsky (Split Hopkinson) compression bar. The single-loading momentum trapping system ensures precise deformation control (1.4, 1.8, 3.0, 4.8, and 9.6 % strain) and single loading during dynamic compression. With increasing strain, the phase transformation peaks shift toward lower temperatures, while the intensities of these peaks decrease and eventually disappear completely at strains above *7 %, where the onset of plastic deformation of reoriented martensite occurs. All transformation peaks are recoverable after deformation simply by annealing at 873 K (600°C) for 30 min, except those peaks corresponding to strains above *7 % (e.g., 9.6 %) which return upon annealing, but at a lower temperature. XRD results showed the variation of the strongest diffraction peak from (1 11) to (111) crystal plane before and after high strain rate compression.

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“…[47] NiTi SMAs also exhibit a dynamic sensitivity. [38,39,48] For martensitic NiTi SMAs, the deformation mechanism and microstructure are not sensitive to the strain rate within the range from 0.002 to 300 s À1 . [49] The stabilization of the martensite under dynamic compression (strain rate: 1000 s À1 ) is similar as that under quasi-static compression.…”

Section: Introductionmentioning

confidence: 99%

“…[13] Precipitates, such as Ni 4 Ti 3 in austenitic (Ni-rich) NiTi alloys and Ti 2 Ni in martensitic (Ti-rich) NiTi alloys, play a significant role in the concentration of Ni in small localized regions, which change the phase transformation temperatures and mechanical properties. Although most dynamic investigations have been focused on austenitic NiTi alloys, [29][30][31][32][33][34][35][36][37][38][39] martensitic NiTi alloys also exhibit thermoelastic behavior and even better damping capacity, [40,41] due to the movement of twin interfaces. NiTi SMAs, which are fully martensitic at room temperature, [42] often have coarse brittle Ti 2 Ni precipitates.…”

Section: Introductionmentioning

confidence: 99%

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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Functional Properties of TiNi Shape Memory Alloy after High Strain Rate Loading

Cited by 14 publications

References 12 publications

Mechanical and structural aspects of high-strain-rate deformation of NiTi alloy

Mechanical and structural aspects of high-strain-rate deformation of NiTi alloy

High Strain Rate Compression of Martensitic NiTi Shape Memory Alloys

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

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