Effect of Aging on Microstructure and Martensitic Transformation in Ti-Zr-Ni Shape Memory Alloys

Sandu, Adrian Mihai; Tsuchiya, Koichi; Yamamoto, Shinya; Tabuchi, Masayuki; Todaka, Yoshikazu; Umemoto, Minoru

doi:10.4028/www.scientific.net/msf.539-543.3163

Cited by 7 publications

(2 citation statements)

References 8 publications

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“…4. Sandu et al 10) reported that Ti-52 mol%Ni-6 mol%Zr wrought alloy has a narrow transformation width and a similar DSC curve to that of our research. This may closely be related to dissolving Zr into TiNi matrix, but, further research is needed.…”

Section: Effect Of Mechanical Alloying On the Microstructuresupporting

confidence: 69%

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Terayama¹,

Nagai

Kyogoku

2009

Mater. Trans.

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This work focuses on the fabrication of Ti-Ni-Zr high-temperature shape memory alloy by powder metallurgy (P/M) process. The effects of fabrication conditions on the microstructure and shape memory characteristics of Ti-50.2 mol%Ni-5 mol%Zr alloy were investigated. In this research, elemental Ti, Ni and Zr powders were used. These powders were mixed by a planetary ball mill at a rotational speed of 500 rpm for milling times of 0.6 ks (mixed powder) and 720 ks (MAed powder). The mixtures were sintered by a pulse-current pressure sintering equipment at 1153 K for sintering times of 1.8 ks and 1.2 ks. The solution treatment was carried out at various temperatures between 1073 K and 1273 K to homogenize the microstructure of the as-sintered alloy. The microstructure of the alloy became more homogeneous with an increase in solutiontreatment temperature. In the case of the mixed powder, however, Zr-rich phases were observed in the microstructure of the solution-treated alloy. The alloy solution-treated at 1173 K showed a yielding behavior in the stress-strain curve, and the tensile strength and elongation of the alloy were more than 350 MPa and 2.5%, respectively. On the other hand, in the case of the MAed powder, the microstructure of the as-sintered alloy was homogeneous. The P/M alloy showed higher transformation temperatures than those of the wrought alloy. But, the alloy showed no shape memory effect and poor tensile property due to contamination of the MAed powder.

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Section: Effect Of Mechanical Alloying On the Microstructuresupporting

confidence: 69%

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Terayama¹,

Nagai

Kyogoku

2009

Mater. Trans.

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“…10) On the other hand, the hardness increased in the initial stage followed by a slight decrease after the longer aging. The aging conditions which give the highest hardness correspond roughly to the one that gives the lowest martensitic transformation temperature.…”

Section: Introductionmentioning

confidence: 99%

Microstructural Evolution during Isothermal Aging in Ni-Rich Ti-Zr-Ni Shape Memory Alloys

et al. 2007

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Microstructural evolution during isothermal aging at temperatures ranging from 673 K to 773 K was investigated by transmission electron microscopy (TEM) for Ni-rich Ti-Zr-Ni alloys. It was revealed that the aging is a two-stage process: the first stage is characterized by circular diffuse scattering in electron diffraction patterns, most likely attributed to short range ordered structure with no significant microstructural change. Second stage is characterized by a fine coherent precipitation followed by the coarsening. The precipitates had a lenticular shape and their habit was f100g B2 . The electron diffraction pattern of the sample containing the precipitates exhibited satellite spots at 1=3h110i B2 and 1=4h210i B2 positions. High resolution TEM observations and fast Fourier transformation analysis revealed that the h100i B2 electron diffraction pattern was composed of the reflection from 4 variants of the precipitates. The two-stage microstructural evolutions coincide well with the previously reported changes in mechanical properties and martensitic transformation behavior.

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Influence of high temperature ternary and quaternary additions on the phase transformation and actuation fatigue characteristics of NiTi shape memory alloys

Sampath

2023

J Therm Anal Calorim

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Effect of Aging on Microstructure and Martensitic Transformation in Ti-Zr-Ni Shape Memory Alloys

Cited by 7 publications

References 8 publications

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Fabrication of Ti-Ni-Zr Shape Memory Alloy by P/M Process

Microstructural Evolution during Isothermal Aging in Ni-Rich Ti-Zr-Ni Shape Memory Alloys

Influence of high temperature ternary and quaternary additions on the phase transformation and actuation fatigue characteristics of NiTi shape memory alloys

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