Effect of second phase precipitation on martensitic transformation and hardness in highly Ni-rich NiTi alloys

Qin, Qiuhui; Peng, Huabei; Fan, Qunchao; Zhang, Lanhui; Wen, Yuhua

doi:10.1016/j.jallcom.2017.12.128

Cited by 46 publications

(10 citation statements)

References 26 publications

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“…Figure 1 illustrates the XRD pattern of the NiTiC1 and NiTiC2 alloys. In the literature, it has been determined that 𝐵19′ martensite, 𝐵2 austenite, and Ni4Ti3 precipitation phases can be formed in NiTi alloys, while TiC phases are generally present in C doped compositions [6,14,[22][23][24][25]. 𝐵2 austenite, Ni4Ti3 precipitation and, TiC phase peaks were found in NiTiC1 and NiTiC2 alloys that are compatible with the literature.…”

Section: Resultssupporting

confidence: 86%

“…NiTiC1 and NiTiC2 alloys showed a one-step phase transformation from martensite to austenite (during the endothermic process) and from austenite to martensite (through the exothermic process) in the heating/cooling curves, i.e., phase transformation occurred as 𝐵19′ → 𝐵2, during heating, and as 𝐵2 → 𝐵19′ during cooling. The low volume fraction of Ni4Ti3 precipitates forming the 𝑅 (Rhombohedral) phase caused no transformation of the 𝑅 phase in the alloys [14]. The austenite and martensite phase transformation temperatures during the transformation are given in Table 4.…”

Section: Resultsmentioning

confidence: 99%

“…Controlling the phase transformation of Ni-rich NiTi SMAs at room temperature is necessary for some of the technologies operating in this range [11][12][13]. However, the presence of metastable intermediate phases (Ni4Ti3, Ni3Ti2) that affect the transformation temperatures in Nirich NiTi alloys are undesirable [11,14]. Researchers are attempting to alloy with a third element to minimize these undesirable phases in Ni-rich NiTi alloys system in a way that does not have a significant effect on phase transformation temperatures [15][16][17][18][19][20].…”

Section: Introductionmentioning

confidence: 99%

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Investigation of Thermal Behavior and Microstructure of Carbon Added NiTi Shape Memory Alloys

ERCAN

2022

International Journal of Innovative Engineering Applications

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Original scientific paperThis study aims to examine the thermal and microstructural properties of NiTiC1 and NiTiC2 shape memory alloys (SMAs) produced by arc-melting method. It was observed that additive C did not alter the phase transformation order which remained as one-step (𝐵2 ↔ 𝐵19′). Additionally, the effect of C addition on thermal properties of the Ni-riched NiTi alloy(s), including temperature hysteresis, enthalpy, entropy, and Gibbs free energies were also determined. An increase in the amount of C noticeably reduced the detectable grain size and thus decreased the elastic energy of the alloy. In DSC analysis, the presence of martensitic phases in the alloys was determined below the room temperature. The presence of B2 austenite, Ni4Ti3 precipitate, and TiC phases were detected in XRD analyses, which were supported by SEM-EDX results. Grain boundaries were clearly observed and precipitates were found to be homogeneously distributed.

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Section: Resultssupporting

confidence: 86%

Section: Resultsmentioning

confidence: 99%

Section: Introductionmentioning

confidence: 99%

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Investigation of Thermal Behavior and Microstructure of Carbon Added NiTi Shape Memory Alloys

ERCAN

2022

International Journal of Innovative Engineering Applications

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“…The EDX analysis results in Table 1 suggest both a eutectic structure and a relatively inhomogeneous and Ti-rich microsegregation, similar to that for as-cast and solution-treated Ni-rich NiTi alloys. 30,31 Qin et al 31 showed that for solution-treated and Table 1. EDX data of the base materials as well as of the first, fifth, and tenth layer of the as-built NiTi-EBF3 specimens.…”

Section: Resultsmentioning

confidence: 99%

The electron beam freeform fabrication of NiTi shape memory alloys. Part I: Microstructure and physical–chemical behavior

Guimarães

Pixner

Trimmel

et al. 2020

Proceedings of the Institution of Mechanical Engineers, Part L:

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Nickel–titanium alloys are the most widely used shape memory alloys due to their outstanding shape memory effect and superelasticity. Additive manufacturing has recently emerged in the fabrication of shape memory alloy but despite substantial advances in powder-based techniques, less attention has been focused on wire-based additive manufacturing. This work reports on the preliminary results for the process-related microstructural and phase transformation changes of Ni-rich nickel–titanium alloy additively manufactured by wire-based electron beam freeform fabrication. To study the feasibility of the process, a simple 10-layer stack structure was successfully built and characterized, exhibiting columnar grains and achieving one-step reversible martensitic–austenitic transformation, thus showing the potential of this additive manufacturing technique for processing shape memory alloys.

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“…The NiTi shape memory alloy was firstly discovered at the US Navy Ordnance Laboratory. The NiTi alloy possesses the advantage of shape memory effect (SME), super elastic (SE) and excellent corrosion resistance [ 1 , 2 , 3 ], which is widely used in automotive, aerospace, and other fields [ 4 , 5 , 6 , 7 , 8 , 9 ]. Chang et al [ 10 ] found the optimal shape memory effect of the NiTi alloy was obtained at 300 °C × 100 h through studying the influence of aging process on the shape memory effect and superelastic properties.…”

Section: Introductionmentioning

confidence: 99%

Research on the Hot Deformation Behavior of the Casting NiTi Alloy

et al. 2021

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The hot deformation behavior and processing maps of the casting NiTi alloy were studied at the deformation temperature of 650–1050 °C and the strain rate of 5 × 10−3–1 s−1 by Gleeble-3800 thermal simulating tester. The variation of the strain rate sensitivity exponent m and the activation energy Q under different deformation conditions (T = 650–1050 °C, ε˙ = 0.005–1 s−1) were obtained. The formability of the NiTi alloy was the best from 800 °C to 950 °C. The constitutive equation of the casting NiTi alloy was constructed by the Arrhenius model. The processing map of the casting NiTi alloy was plotted according to the dynamic material model (DMM) based on the Prasad instability criterion. The optimal processing areas were at 800–950 °C and 0.005–0.05 s−1. The microstructure of the casting NiTi alloy was analyzed by TEM, SEM and EBSD. The softening mechanisms of the casting NiTi alloy were mainly dynamic recrystallization of the Ti2Ni phase and the nucleation and growth of fine martensite.

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Effect of second phase precipitation on martensitic transformation and hardness in highly Ni-rich NiTi alloys

Cited by 46 publications

References 26 publications

Investigation of Thermal Behavior and Microstructure of Carbon Added NiTi Shape Memory Alloys

Investigation of Thermal Behavior and Microstructure of Carbon Added NiTi Shape Memory Alloys

The electron beam freeform fabrication of NiTi shape memory alloys. Part I: Microstructure and physical–chemical behavior

Research on the Hot Deformation Behavior of the Casting NiTi Alloy

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