High performance shape memory effect in nitinol wire for actuators with increased operating temperature range

2014 ◽  
Vol 07 (05) ◽  
pp. 1450063 ◽  
Author(s):  
Riccardo Casati ◽  
Carlo Alberto Biffi ◽  
Maurizio Vedani ◽  
Ausonio Tuissi
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
High Performance ◽  
Room Temperature ◽  
Operating Temperature ◽  
Niti Wire ◽  
Shape Memory Actuators ◽  
Nitinol Wire ◽  
Operating Temperature Range

In this research, the high performance shape memory effect (HP-SME) is experimented on a shape memory NiTi wire, with austenite finish temperature higher than room temperature. The HP-SME consists in the thermal cycling of stress induced martensite and it allows achieving mechanical work higher than that produced by conventional shape memory actuators based on the heating/cooling of detwinned martensite. The Nitinol wire was able to recover about 5.5% of deformation under a stress of 600 MPa and to withstand about 5000 cycles before failure. HP-SME path increased the operating temperature of the shape memory actuator wire. Functioning temperatures higher than 100°C was reached.

Tensile Failure of 55-Nitinol Wire

1975 ◽  
Vol 33 ◽  
pp. 46-47
Author(s):  
F. I. Grace
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Stoichiometric Composition ◽  
Tensile Failure ◽  
Initial State ◽  
Initial Shape ◽  
Nitinol Wire ◽  
Cscl Type ◽  
Shear Transformation

An interest in NiTi alloys with near stoichiometric composition (55 NiTi) has intensified since they were found to exhibit a unique mechanical shape memory effect at the Naval Ordnance Laboratory some twelve years ago (thus refered to as NITINOL alloys). Since then, the microstructural mechanisms associated with the shape memory effect have been investigated and several interesting engineering applications have appeared.The shape memory effect implies that the alloy deformed from an initial shape will spontaneously return to that initial state upon heating. This behavior is reported to be related to a diffusionless shear transformation which takes place between similar but slightly different CsCl type structures.

Cold Bending a Ni-Ti Shape Memory Alloy Wire

2015 ◽  
Vol 661 ◽  
pp. 98-104 ◽  
Author(s):  
Kuang-Jau Fann ◽  
Pao Min Huang
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
Aging Treatment ◽  
Treatment Temperature ◽  
Bending Test ◽  
Solution Treatment Temperature

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.

SHAPE MEMORY INVESTIGATION OF SMART CAMAR LOGO USING NITI ALLOY WIRE

2015 ◽  
Vol 76 (3) ◽  
Author(s):  
Muhammad Safwan Shuhaimi ◽  
Nubailah Abd. Hamid ◽  
Rosliza Razali ◽  
Muhammad Hussain Ismail
Keyword(s):  
Phase Transformation ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Niti Alloy ◽  
Niti Shape Memory Alloy ◽  
Shape Effect ◽  
Niti Wire ◽  
The Wire ◽  
Reversible Phase

This project is investigates of NiTi shape memory alloy for simple smart application. The shape memory effect (SME) is attributed from the reversible phase transformation when subjected to stress and temperature. In this study, a small model of CAMAR logo was designed to mimic the shape memory effect. Three samples of wire were investigated; (i) Austenitic NiTi (ii) Martensitic NiTi and (iii) commercial plain carbon steel. The reversible austenite to martensite transformation of the NiTi wire was investigated by a differential scanning calorimetry (DSC) at temperatures ranging from -50 and 200oC. The wire was shaped into CAMAR logo using a mould and then heated at 500°C for 30 minutes in a high temperature furnace. To observe the shape effect recovery, the wire was straighten and reheated in warm water at different temperatures. Results showed that the austenitic wire exhibited complete shape memory recovery after heated at temperature approximately 35°C and  80°C. For the martensitic wire, complete recovery was only observed when the water temperature was ~ 80°C and no recovery was observed at ~30°C. This recovery effect was significantly influenced by the reversible phase transformation temperatures (PTTs) which attributed from the Austenite finish (Af) temperature.

Improving the structure stabilization of red phosphorus anodes via the shape memory effect of a Ni–Ti alloy for high-performance sodium ion batteries

2019 ◽  
Vol 55 (32) ◽  
pp. 4659-4662 ◽  
Author(s):  
Yingtao Wang ◽  
Xiaodan Yang ◽  
Chenyang Zhao ◽  
Yongliang Li ◽  
Hongwei Mi ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
High Performance ◽  
Sodium Ion ◽  
Sodium Ion Batteries ◽  
Ti Alloy ◽  
Red Phosphorus ◽  
Structure Degradation ◽  
Structure Stabilization

The shape memory effect of a Ni–Ti alloy was applied to prevent the structure degradation of red phosphorus anodes for sodium-ion batteries.

The Shape Memory Effect in Melt Spun Fe-15Mn-5Si-9Cr-5Ni Alloys

2013 ◽  
Vol 738-739 ◽  
pp. 247-251 ◽  
Author(s):  
Ana Druker ◽  
Paulo La Roca ◽  
Philippe Vermaut ◽  
Patrick Ochim ◽  
Jorge Malarría
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Melt Spinning ◽  
Room Temperature ◽  
Tensile Tests ◽  
Argon Atmosphere ◽  
Austenitic Phase ◽  
Melt Spun ◽  
Shape Memory Behaviour

At room temperature, Fe-15Mn-5Si-9Cr-5Ni alloys are usually austenitic and the application of a stress induces a reversible martensitic transformation leading to a shape memory effect (SME). However, when a ribbon of this material is obtained by melt-spinning, the rapid solidification stabilizes a high-temperature ferritic phase. The goals of this work were to find the appropriate heat treatment in order to recover the equilibrium austenitic phase, characterize the ribbon form of this material and evaluate its shape memory behaviour. We found that annealing at 1050°C for 60 min, under a protective argon atmosphere, followed by a water quenching stabilizes the austenite to room temperature. The yield stress, measured by tensile tests, is 250 MPa. Shape-memory tests show that a strain recovery of 55% can be obtained, which is enough for certain applications.

Shape Memory Effect Improvement and Study of the Corrosion Resistance of the Fe-8Mn-6Si-13Cr-6Ni-12Co Alloy

2012 ◽  
Vol 476-478 ◽  
pp. 2162-2170 ◽  
Author(s):  
Amine Charfi ◽  
Fehmi Gamaoun ◽  
Tarak Bouraoui ◽  
Chedly Bradai ◽  
Bernard Normand
Keyword(s):  
Corrosion Resistance ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
316L Stainless Steel ◽  
Experimental Tests ◽  
Good Corrosion Resistance ◽  
Resistance Tests ◽  
Better Than

Fe-8Mn-6Si-13Cr-6Ni-12Co shape memory alloys are characterized by a good corrosion resistance and a modest shape memory effect. Experimental tests of the corrosion resistance of Fe-8Mn-6Si-13Cr-6Ni-12Co have been studied and compared with the Fe-32Mn-6Si alloy using weight loss, free corrosion and polarization resistance tests. The shape memory effect measurement of the Fe-8Mn-6Si-13Cr-6Ni-12Co and Fe-32Mn-6Si alloys has been also tested after 5% of deformation. The results of corrosion experimental tests show that the Fe-8Mn-6Si-13Cr-6Ni-12Co SMA is not very active in the Na2SO4 solution at pH4 at room temperature. In addition, its corrosion resistance is better than the Fe-32Mn-6Si and almost similar to the 316L stainless steel. To improve the shape memory effect of the Fe-8Mn-6Si-13Cr-6Ni-12Co, a thermomechanical treatment has been applied by 8% prestrain in tensile and followed by heat treatment at 1320K for 1 hour. The results show an improvement in the shape memory effect after 5% of deformation in tensile test.

Towards Novel Light-Activated Shape Memory Polymer: Thermomechanical Properties of Photo-responsive Polymers

2005 ◽  
Vol 872 ◽  
Author(s):  
Emily A. Snyder ◽  
Tat H. Tong
Keyword(s):  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Room Temperature ◽  
Shape Memory Polymer ◽  
Crosslinking Density ◽  
Material System ◽  
Effect Change ◽  
Responsive Polymers ◽  
Original Shape

AbstractThe basic principle for the operation of a thermally stimulated shape memory polymer (SMP) is a drastic change in elastic modulus above the glass transition temperature (Tg). This change from glassy modulus to rubbery modulus allows the material to be deformed above the Tg and retain the deformed shape when cooled below the Tg. The material will recover its original shape when heated above the Tg again. However, thermal activation is not the only possibility for a polymer to exhibit this shape memory effect or change of modulus. This paper discusses results of an alternative approach to SMP activation.It is well known that the Tg of a thermosetting polymer is proportional to its crosslinking density. It is possible for the crosslinking density of a room temperature elastomer to be modified through photo-crosslinking special photo-reactive monomer groups incorporated into the material system in order to increase its Tg. Correspondingly, the modulus will be increased from the rubbery state to the glassy state. As a result, the material is transformed from an elastomer to a rigid glassy photoset, depending on the crosslinking density achieved during exposure to the proper wavelength of light. This crosslinking process is reversible by irradiation with a different wavelength, thus making it possible to produce light-activated SMP materials that could be deformed at room temperature, held in deformed shape by photo-irradiation using one wavelength, and recovered to the original shape by irradiation with a different wavelength.In this work, monomers which contain photo-crosslinkable groups in addition to the primary polymerizable groups were synthesized. These monomers were formulated and cured with other monomers to form photo-responsive polymers. The mechanical properties of these materials, the kinetics, and the reversibility of the photo-activated shape memory effect were studied to demonstrate the effectiveness of using photo-irradiation to effect change in modulus (and thus shape memory effect).

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