Enhancement of Shape Memory Properties through Precipitation Hardening in a Ti-Rich Ti-Ni-Pd High Temperature Shape Memory Alloy

Namigata, Yuki; Hattori, Yoshitaka; Khan, Mushtaq; Kim, Hee-Young; Miyazaki, Shuichi

doi:10.2320/matertrans.mb201516

Cited by 11 publications

(6 citation statements)

References 32 publications

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“…The P-phase has a slightly Ti-poor composition and thus occurs above all in Ti-lean alloys and may form already at low temperatures, as shown by Hattori et al, cycling the Ni-Ti-Pd alloys up to 400 • C [22]. On the other hand, the same work and also Namigata et al [21] attest these alloys high performance regarding dimensional stability, recovery ratio and work output during thermal cycling under stress due to the presence of the nanometer-sized precipitates.…”

Section: Introductionmentioning

confidence: 62%

“…Systems, which became particularly popular because they combine low-hysteresis width with high transformation temperature opportunities, are the Ni-Ti-Pd and Ni-Ti-Cu-Pd ones. Intensive research on the ternary system initiated in the early 1990s, and it remains a fascinating field of investigation for improving shape memory alloy performance today [19][20][21][22]. In these alloys, Pd usually substitutes for Ni, and the microstructure remains near-monophasic close to the stoichiometric Ti : (Ni + Pd) ≈ 1 compositions [19,20].…”

Section: Introductionmentioning

confidence: 99%

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Low-Hysteresis Shape Memory Alloy Scale-Up: DSC, XRD and Microstructure Analysis on Heat-Treated Vacuum Induction Melted Ni-Ti-Cu-Pd Alloys

Lemke

Gallino

Cresci

et al. 2021

Metals

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Quaternary Ni-Ti-Cu-Pd formulations were cast by vacuum induction melting (VIM) with the aim of preparing low-hysteresis shape memory alloys and verifying the applicability of the Co-Factor theory in conventional industrial manufacturing processes. The cast alloys showed lower transformation hysteresis width in DSC measurements than binary Ni-Ti, but struggled to achieve a near zero hysteresis, as predicted by the theoretical framework, despite being close to satisfy the first Co-Factor condition (CC I) that foresees minimum hysteresis for formulations in which the middle eigenvalue of the martensitic transformation matrix λ2 approaches one. The microstructure of the annealed Ni-Ti-Cu-Pd alloys exhibited a considerable amount of mostly sub-micron-sized secondary phases, which distort the matrix composition and prevent it from reaching the optimum stoichiometry for satisfying the CC I. In addition, this class of materials is prone to aging effects, leading to the formation of semi-coherent tetragonal precipitates, which tend to also form at the grain boundaries after low-temperature annealing, further affecting the transformation hysteresis in DSC experiments depending on the thermal history. This work reveals the importance of considering typical casting effects that alter the theoretical λ2 of ideal materials in the compositional design for the development of high-performance low-hysteresis alloys.

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Section: Introductionmentioning

confidence: 62%

Section: Introductionmentioning

confidence: 99%

Low-Hysteresis Shape Memory Alloy Scale-Up: DSC, XRD and Microstructure Analysis on Heat-Treated Vacuum Induction Melted Ni-Ti-Cu-Pd Alloys

Lemke

Gallino

Cresci

et al. 2021

Metals

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“…Figure 5a,b shows the selected area diffraction pattern (SADP) with a [001] B2 zone axis and a dark field micrograph obtained from the 52Ti alloy cycled five times from 273 K to 673 K. The diffraction pattern reveals extra diffuse streaks noted by arrows in between the primary diffraction spots from the B2 phase. The diffuse streaks were identified as the Ti 2 Pd phase [36,43]. The dark field micrograph taken by using the diffuse streak clearly shows the formation of fine needle-shaped precipitates.…”

Section: Resultsmentioning

confidence: 99%

“…Therefore, one of the key issues in researching Ti–Ni–Pd alloys is the improvement of resistance to permanent deformation upon actuation cycles at higher working temperature ranges. There have been various approaches to improve shape memory properties at higher temperatures such as (1) grain size refinement through severe plastic deformation [28], (2) the addition of quaternary elements [29,30,31] and (3) precipitation strengthening [25,32,33,34,35,36]. The combination of multiple strengthening mechanisms has been found to be effective for increasing strength and improving shape memory properties [37,38].…”

Section: Introductionmentioning

confidence: 99%

Effect of Stoichiometry on Shape Memory Properties and Functional Stability of Ti–Ni–Pd Alloys

et al. 2019

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Ti–Ni–Pd shape memory alloys are promising candidates for high-temperature actuators operating at above 373 K. One of the key issues in developing high-temperature shape memory alloys is the degradation of shape memory properties and dimensional stabilities because plastic deformation becomes more pronounced at higher working temperature ranges. In this study, the effect of the Ti:(Ni + Pd) atomic ratio in TixNi70−xPd30 alloys with Ti content in the range from 49 at.% to 52 at.% on the martensitic transformation temperatures, microstructures and shape memory properties during thermal cycling under constant stresses were investigated. The martensitic transformation temperatures decreased with increasing or decreasing Ti content from the stoichiometric composition. In both Ti-rich and Ti-lean alloys, the transformation temperatures decreased during thermal cycling and the degree of decrease in the transformation temperatures became more pronounced as the composition of the alloy departed from the stoichiometric composition. Ti2Pd and P phases were formed during thermal cycling in Ti-rich and Ti-lean alloys, respectively. Both Ti-rich and Ti-lean alloys exhibited superior dimensional stabilities and excellent shape memory properties with higher recovery ratio and larger work output during thermal cycling under constant stresses when compared with the alloys with near-stoichiometric composition.

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“…2,3) Various types of high temperature SMAs (HTSMAs), such as Ti-Ni-(Zr, Hf, Pd, Au, Pt) Ti-Ni-Hf-Pd, Ti-Ni-Hf-Y, Ti-Zr-Pd, Ti-Zr-Ni-Pd, Ti-Pt and Ti-Pt-Ir alloys have been developed. [3][4][5][6][7][8][9][10][11] Especially, Ti-Ni-Zr, Ti-Ni-Hf and Ti-Ni-Zr-Hf alloys have been considered as good candidates of HTSMAs because of their relatively low-cost compared with the alloys containing a large amount of noble elements. [12][13][14] Recently, multi-principal element alloys or high-entropy alloys have attracted attentions due to the high strength caused by large lattice distortions.…”

Section: Introductionmentioning

confidence: 99%

Development of Ni–Ti–Zr–Hf–(Nb, Ta) Multi-Principal Element High-Temperature Shape Memory Alloys with High Cold Workability

Tasaki,

Arai,

Miyazaki

et al. 2023

Mater. Trans.

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Novel Ni-Ti-Zr-Hf-Nb and Ni-Ti-Zr-Hf-Ta high temperature shape memory alloys with multi-principal elements were developed, and differences in the effects of Nb and Ta on cold workability and shape memory properties were investigated. Constituent phases, microstructure, cold workability, transformation temperatures, shape memory properties were investigated in (Ni 50 Ti 30 Zr 10 Hf 10 ) 100¹x Nb x (x = 5, 10, 15) alloys and (Ni 50 Ti 30 Zr 10 Hf 10 ) 100¹y Ta y ( y = 5, 10, 15) alloys. Although both of Nb and Ta were effective to improve cold workability of Ni 50 Ti 30 Zr 10 Hf 10 alloy by forming a ductile ¢ phase with a disordered body-centered cubic structure, it was found that Ta was more effective than Nb in improving cold workability. The addition of Ta was also effective to suppress the formation of Ti 2 Ni-type intermetallic compound. Transformation temperatures were not significantly affected by the addition of Nb, while the transformation temperatures increased by the addition of Ta. According to thermal cycling tests, the (Ni 50 Ti 30 Zr 10 Hf 10 ) 85 Nb 15 , (Ni 50 Ti 30 Zr 10 Hf 10 ) 90 Ta 10 and (Ni 50 Ti 30 Zr 10 Hf 10 ) 85 Ta 15 alloys exhibited almost full shape recovery under 200 MPa. These alloys are suggested as promising candidates for practical high temperature shape memory alloys that can be worked at room temperature.

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Enhancement of Shape Memory Properties through Precipitation Hardening in a Ti-Rich Ti-Ni-Pd High Temperature Shape Memory Alloy

Abstract: Effects of aging on martensitic transformation temperature, microstructure and shape memory characteristics were investigated for Ti 50

Cited by 11 publications

References 32 publications

Low-Hysteresis Shape Memory Alloy Scale-Up: DSC, XRD and Microstructure Analysis on Heat-Treated Vacuum Induction Melted Ni-Ti-Cu-Pd Alloys

Low-Hysteresis Shape Memory Alloy Scale-Up: DSC, XRD and Microstructure Analysis on Heat-Treated Vacuum Induction Melted Ni-Ti-Cu-Pd Alloys

Effect of Stoichiometry on Shape Memory Properties and Functional Stability of Ti–Ni–Pd Alloys

Development of Ni–Ti–Zr–Hf–(Nb, Ta) Multi-Principal Element High-Temperature Shape Memory Alloys with High Cold Workability

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