ECAP based regulation mechanism of shape memory properties of NiTiNb alloys

Yang, Zhiwei; Li, Heng; Zhang, Yanhong; Liu, Xin; Gu, Qingfei; Liu, Yuli

doi:10.1016/j.jallcom.2021.163184

Cited by 13 publications

(3 citation statements)

References 36 publications

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“…During the preparation process, the temporal and spatial The OM diagrams of sample L7 and sample L8 are shown in Figure 9. Compared with the microstructure parallel to the forging direction in the hot forged structure, which shows large and highly elongated grains [9,10], the NiTiNb microstructure prepared by LSF is closer to the cast microstructure. From the low magnification OM image, it can be observed that there are epitaxially grown columnar grains at position 1 parallel to the building direction [49] (Figure 9a).…”

Section: Microstructure Featuresmentioning

confidence: 90%

“…Because of the unique functional characteristics of NiTi-based SMA such as good biocompatibility [2], excellent corrosion resistance [3], excellent mechanical properties [4], NiTi-based SMA has a strong application potential [5] in aerospace [6], automation [7], medicine [8] as well as in daily life. NiTiNb shape memory alloy with Nb addition and NiTiFe shape memory alloy with Fe addition can be applied to pipeline connections of an aeroengine [9,10]. While NiTiNb has more potential because of the characteristics of wide hysteresis, the maximum phase transformation hysteresis temperature of pre-deformed NiTiNb alloy can reach 150 • C. A connector made of NiTiNb alloy can be stored, transported, and installed at room temperature, saving economic and time costs.…”

Section: Introductionmentioning

confidence: 99%

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Microstructure and Phase Transformation Temperature of NiTiNb Shape Memory Alloy Prepared by Laser Solid Forming Using Mixed Powder

Yang

et al. 2022

Applied Sciences

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NiTiNb is a wide-hysteresis shape memory alloy. The Laser Solid Forming (LSF) technology can overcome the shortcomings of the traditional long cycle processing to prepare NiTiNb. In this work, we studied the microstructure and phase transformation temperature of the NiTiNb prepared by LSF., in which the Ni + Ti + Nb mixed powder was melted under different laser power P, scanning speed v, layer thickness t, and energy density EV. The results show that the combination of LSF process parameters with P = 2000 W and v = 900 mm/min can obtain a good metallurgical bond. As the laser power increases, the grain size increases, and the proportion of equiaxed crystals increases, the martensite transformation temperature increases. The inhomogeneity of the LSF-NiTiNb microstructure results in different phase transformation temperatures even in the same sample. The subsequent heat treatment at 850 °C for 3 h increases the phase transformation temperature and hysteresis of LSF-NiTiNb. The tensile properties of the LSF-NiTiNb samples with different building heights are significantly different. The maximum elongation reaches 8% and the minimum elongation is only 0.8%. The LSF parameter combination in this work has reference value for the parameter selection of subsequent preparation of NiTiNb.

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Section: Microstructure Featuresmentioning

confidence: 90%

Section: Introductionmentioning

confidence: 99%

Microstructure and Phase Transformation Temperature of NiTiNb Shape Memory Alloy Prepared by Laser Solid Forming Using Mixed Powder

Yang

et al. 2022

Applied Sciences

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“…As a result, the dynamic compressive test shows a significant strength increase attributed to the precipitates and the strength improvement from grain size refinement (Hall-Petch effect). Yang et al [11] processed Ni-Ti-Nb SMAs by ECAP. Ni-Ti-Nb is a wide hysteresis shape memory alloy with great application potential in aerospace.…”

Section: Introductionmentioning

confidence: 99%

Behaviors of Thermoelastic Properties in Ni-Ti Based Shape Memory Alloys, Processed by Metal Forming Techniques

Tenório Luna da Silva,

Virgolino,

Silva

et al. 2023

IIUMEJ

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In this work, the thermoelastic properties of Ni-Ti shape memory alloys (SMA) processed by conventional rolling and equal channel angular extrusion (ECAE) were investigated. SMAs have two phases: Austenite (at high temperature) and Martensite (at low temperature). The samples were compared under five different thermal and processing conditions: homogenized, rolled, rolled-annealed, extruded, and extruded-annealed. The homogenized sample served as a reference. The samples were analyzed by differential scanning calorimetry (DSC) to determine the thermoelastic transformation temperatures. Images were taken using scanning electronic microscopy (SEM) in conjunction with energy dispersive spectroscopy (EDS). The dynamic area was completed for two tests: under constant load bending (simulation of the memory effect to determine the reversible thermoelastic strain) and dynamic mechanical analysis (DMA). The results showed that the plastic forming processes alter the properties, especially for samples exposed to the ECAE, which can block the martensitic phase. However, R-phase (a rhombohedral phase), that can appear at low temperatures before the martensitic phase, emerges totally when the extruded sample suffers annealing. The images of SEM, confirmed by EDS, show that any type of forming process and the presence of precipitates have a significant influence on the behavior of the elastic property. It was found that extrusion has a greater effect on the restoring properties of the alloys than rolling. This analysis is of great importance for the use of SMA in applications requiring high mechanical strength combined with the functional properties of shape recovery through martensitic phase transformations. ABSTRAK: Kajian ini adalah berkaitan sifat-sifat bentuk aloi ingatan (SMA) termoelastik Ni-Ti yang diproses melalui penggelek konvensional dan penyemperitan sudut saluran sama (ECAE). SMA mempunyai dua peringkat: Austenit (pada suhu tinggi) dan Martensit (pada suhu rendah). Sampel dibandingkan pada lima tahap kepanasan dan proses iaitu: percampuran, penggulungan, penggulungan-rataan, perataan dan penyemperitan-rataan. Sampel campuran yang dihomogenkan dijadikan sebagai sampel rujukan. Sampel dianalisis dengan pengimbas kalorimetri pembezaan (DSC) bagi menentukan suhu transformasi termoelastik. Imej diambil menggunakan pengimbas mikroskop elektronik (SEM) bersama spektroskopi penyebaran tenaga (EDS). Kawasan dinamik diuji dengan dua ujian: di bawah lenturan beban malar (simulasi kesan memori bagi menentukan terikan termoelastik boleh balik) dan analisis mekanik dinamik (DMA). Dapatan kajian menunjukkan bahawa proses pembentukan plastik telah mengubah sifat, terutama pada sampel yang terdedah kepada penyemperitan sudut saluran sama ECAE, yang boleh menyekat fasa martensit. Walau bagaimanapun, fasa-R (fasa rombohedral) yang boleh muncul pada suhu rendah sebelum fasa martensitik, muncul sepenuhnya apabila sampel tersemperit mengalami penyepuhlindapan (penyemperitan-rataan). Imej pengimbasan mikroskop elektron, seperti yang dibuktikan dengan spektroskopi penyebaran tenaga (EDS), menunjukkan bahawa apa-apa jenis proses pembentukan dan kehadiran mendakan mempunyai pengaruh kuat terhadap sifat elastik. Dapatan kajian juga mendapati bahawa penyemperitan mempunyai kesan yang lebih besar terhadap sifat pemulihan aloi berbanding proses penggulungan. Analisis ini sangat penting bagi penggunaan bentuk aloi ingatan (SMA) dalam aplikasi yang memerlukan kekuatan mekanikal yang tinggi bersama sifat pemulihan bentuk melalui transformasi fasa martensit.

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Widening the Martensitic Hysteresis in Ni47Ti44Nb9 Shape Memory Alloy by Grain Refinement

Cao,

Fan,

Sun

et al. 2024

Metall Mater Trans A

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ECAP based regulation mechanism of shape memory properties of NiTiNb alloys

Cited by 13 publications

References 36 publications

Microstructure and Phase Transformation Temperature of NiTiNb Shape Memory Alloy Prepared by Laser Solid Forming Using Mixed Powder

Microstructure and Phase Transformation Temperature of NiTiNb Shape Memory Alloy Prepared by Laser Solid Forming Using Mixed Powder

Behaviors of Thermoelastic Properties in Ni-Ti Based Shape Memory Alloys, Processed by Metal Forming Techniques

Widening the Martensitic Hysteresis in Ni47Ti44Nb9 Shape Memory Alloy by Grain Refinement

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