An Active Guide Wire With Shape Memory Alloy Bending Actuator Fabricated By Room Temperature Process

2001 ◽  
pp. 698-701 ◽  
Author(s):  
Takashi Mineta ◽  
Toshiaki Mitsui ◽  
Yoshiyuki Watanabe ◽  
Seiya Kobayashi ◽  
Youichi Haga ◽  
...  
2002 ◽  
Vol 97-98 ◽  
pp. 632-637 ◽  
Author(s):  
Takashi Mineta ◽  
Toshiaki Mitsui ◽  
Yoshiyuki Watanabe ◽  
Seiya Kobayashi ◽  
Youichi Haga ◽  
...  

2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang

Because of being in possession of shape memory effect and superelasticity, Ni-Ti shape memory alloys have earned more intense gaze on the next generation applications. Conventionally, Ni-Ti shape memory alloys are manufactured by hot forming and constraint aging, which need a capital-intensive investment. To have a cost benefit getting rid of plenty of die sets, this study is aimed to form Ni-Ti shape memory alloys at room temperature and to age them at elevated temperature without any die sets. In this study, starting with solution treatments at various temperatures, which served as annealing process, Ni-rich Ni-Ti shape memory alloy wires were bent by V-shaped punches in different curvatures at room temperature. Subsequently, the wires were aged at different temperatures to have shape memory effect. As a result, springback was found after withdrawing the bending punch and further after the aging treatment as well. A higher solution treatment temperature or a smaller bending radius leads to a smaller springback, while a higher aging treatment temperature made a larger springback. This springback may be compensated by bending the wires in further larger curvatures to keep the shape accuracy as designed. To explore the shape memory effect, a reverse bending test was performed. It shows that all bent wires after aging had a shape recovery rate above 96.3% on average.


2009 ◽  
Vol 618-619 ◽  
pp. 319-323 ◽  
Author(s):  
Parama Chakraborty Banerjee ◽  
Tao Sun ◽  
Jonathan H.W. Wong ◽  
Min Wang

To improve the biocompatibility and bioactivity of NiTi shape memory alloy (SMA), apatite/collagen composite coatings were fabricated on the surface of NiTi SMA at room temperature using the electrochemical deposition technique. Spherical apatite particles and fibrous collagen that formed the composite coating were visible under scanning electron microscope (SEM). The Ca/P ratio of the apatite component in the coating, as determined by energy dispersive X-ray spectroscopy (EDX), was about 1.38 which is slightly higher than that of octocalcium phosphate (OCP). X-ray diffraction result showed that the apatite was amorphous, which was due to the low temperature (i.e., room temperature) deposition process. The structure of the composite coatings was further characterized using Fourier transform infrared reflection spectroscopy (FTIR). It was also found that, compared to bare NiTi SMA samples, the wettability of as-deposited samples was increased because of the formation of the composite coating.


2017 ◽  
Vol 907 ◽  
pp. 8-13 ◽  
Author(s):  
Lucian Burlacu ◽  
Nicanor Cimpoeşu ◽  
Nicoleta Monica Lohan ◽  
Leandru Gheorghe Bujoreanu

The paper introduces the possibility to replace the “wet alloy”, used for sprinkler-triggering within automatic fire protection systems, with a shape memory alloy (SMA) type. The idea of the present application is based on the thermoelastic reversible martensitic transformation, governing SMA functioning, which has completely reversible character, and enables the occurrence of two-way shape memory effect (TWSME) after the application of a thermomechanical treatment called “training”. For this purpose a commercial NiTi rod, which was martensitic at room temperature, was subjected to thermal analysis tests, performed by differential scanning calorimetry (DSC) and dilatometry. Martensite (M) reversion to parent phase (A), during heating, was emphasized by an endothermic peak on the DSC thermogram and by a length shrinkage, on the dilatogram. The capacity to develop TWSME was revealed by the change in displacement-temperature variation, with increasing the number of training cycles. This stabilized fully reversible behavior recommends NiTi rods as executive elements of a new concept of resettable sprinkler for fire protection.


2011 ◽  
Vol 418-420 ◽  
pp. 222-227
Author(s):  
Zhi Jian Zhang ◽  
Nai Chao Si ◽  
Guang Lei Liu ◽  
Song Hai Si

The TiNiV shape memory alloy wire that was cold pressed under 9Mpa at the room temperature had good superelasticity. On this basis, a tensile test was made after a series of medium-temperature treatment. Then the effect of superelasticity and microstructure of TiNiV shape memory alloy by medium-temperature treatment were studied. The results indicate that the experimental wires assume thorough non-linear superelasticity after holding 30 min at 430°C. The superelasticity of the wire enhances firstly, then declines with the ascent of the temperature and extension of the time of the holding. A kind of potentiation phase-Ti3Ni4 precipites out of the wire under different medium-temperature treatment.


Sign in / Sign up

Export Citation Format

Share Document