Shape-memory behaviors in an aged Ni-rich TiNiHf high temperature shape-memory alloy

Meng, Xianglong; Cai, Wei; Fu, Yong Qing; Li, Q.F.; Zhang, J.X.; Zhao, Liancheng

doi:10.1016/j.intermet.2008.02.005

Cited by 84 publications

(36 citation statements)

References 23 publications

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“…It has been shown that the martensitic transformation temperatures of NiTi-based alloys can be changed [12][13][14][15][16][17][18][19][20][21][22][23][24][25][26][27][28][29][30][31] as a result of aging. Tables 1 and 2 list the martensitic transformation temperatures of a number of solution-treated and aged NiTi-based alloys that experience a considerable change in M s temperature (>15 C).…”

Section: Precipitation and Change Of M Smentioning

confidence: 99%

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Transformation temperature changes due to second phase precipitation in NiTi-based shape memory alloys

2009

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Section: Precipitation and Change Of M Smentioning

confidence: 99%

“…In NiTi [2,21], Ni-rich NiTiHf [27], and NiTiPt [12], precipitation of Ni 4 Ti 3 , Ni 4 (Ti,Hf) 3 , and NiTiPt compounds, respectively, results in a considerable increase of M s (Table 1). In contrast, in the second group of NiTi-based alloys, precipitation results in a decrease of the M s temperature.…”

Section: Precipitation and Change Of M Smentioning

confidence: 99%

Transformation temperature changes due to second phase precipitation in NiTi-based shape memory alloys

2009

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“…[13]. In particular, NiTiHf has been developed as a low cost alternative when compared to NiTi-X (X ¼ Pt, Pd, Au), and just recently, Ni-rich NiTiHf alloys were found to exhibit superior properties and dimensional stability through compositional and aging control [7e 12,14,15]. This was accomplished by developing a slightly Ni-rich composition with 20 at.% Hf, that is capable of being precipitation strengthened when subjected to an aging heat treatment to produce fine, nanometer size precipitates.…”

Section: Introductionmentioning

confidence: 99%

Mechanical and functional behavior of a Ni-rich Ni50.3Ti29.7Hf20 high temperature shape memory alloy

et al. 2014

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a b s t r a c tThe mechanical and functional behaviors of a Ni-rich Ni 50.3 Ti 29.7 Hf 20 high temperature shape memory alloy were investigated through combined ex situ macroscopic experiments and in situ synchrotron X-ray diffraction. Isothermal tension and compression tests were conducted between room temperature and 260 C, while isobaric thermomechanical cycling experiments were conducted at selected stresses up to 700 MPa. Isothermal testing of the martensite phase revealed no plastic strain up to the test limit of 1 GPa and near-perfect superelastic behavior up to 3% applied strain at temperatures above the austenite finish. Excellent dimensional stability with greater than 2.5% actuation strain without accumulation of noticeable residual strains (at stresses less than or equal to À400 MPa) were observed during isobaric thermal cycling experiments. The absence of residual strain accumulation during thermomechanical cycling was confirmed by the lattice strains, determined from X-ray spectra. Even in the untrained condition, the material exhibited little or no history or path dependence in behavior, consistent with measurements of the bulk texture after thermomechanical cycling using synchrotron X-ray diffraction. Post deformation cycling revealed the limited conditions under which a slight two-way shape memory effect (TWSME) was obtained, with a maximum of 0.34% two-way shape memory strain after thermomechanical cycling under À700 MPa.Published by Elsevier Ltd.

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“…Early work on NiTiHf alloys has given insight on the physical metallurgy and metallurgical processing studies [63][64][65]. Few preliminary studies on the mechanical behavior of different Hf contents were made from early 2000, in particular focusing on the shape memory response of bent plates [66][67][68]. Because of elastic recovery and tension-compression symmetry it is difficult to interpret bending results.…”

Section: Overview Of Previous Nitihf Workmentioning

confidence: 99%

Shape memory strains and temperatures in the extreme

Şehitoğlu

Patriarca

2017

Current Opinion in Solid State and Materials Science

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It is well known that the achievement of high transformation strains in shape memory alloys (SMAs) has been curtailed by plastic deformation mediated via dislocation slip. In particular, the utilization of SMAs at high temperatures is also hindered by plastic slip. In this paper, an overview of the most important SMAs is provided by constructing transformation strain, transformation temperature, and slip resistance plots to put existing works in perspective. To this plots, we added results on NiTiHf alloys which impart both high temperature capability and high slip resistance at unprecedented levels. The remarkable finding is that NiTiHf alloys can undergo transformation strains near 20% and transformation temperatures exceeding 400 °C

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Shape-memory behaviors in an aged Ni-rich TiNiHf high temperature shape-memory alloy

Cited by 84 publications

References 23 publications

Transformation temperature changes due to second phase precipitation in NiTi-based shape memory alloys

Transformation temperature changes due to second phase precipitation in NiTi-based shape memory alloys

Mechanical and functional behavior of a Ni-rich Ni50.3Ti29.7Hf20 high temperature shape memory alloy

Shape memory strains and temperatures in the extreme

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