Ca2+, redox, and thermoresponsive supramolecular hydrogel with programmed quadruple shape memory effect

With a new redox-responsive stimulus coupled with two other common regulation mechanisms, this hydrogel shows programmed quadruple shape memory behaviour.

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Stretchable supramolecular hydrogels with triple shape memory effect

Chemical Science ◽

10.1039/c6sc02354a ◽

2016 ◽

Vol 7 (11) ◽

pp. 6715-6720 ◽

Cited By ~ 89

Author(s):

Xiaoxia Le ◽

Wei Lu ◽

Jing Zheng ◽

Dingyi Tong ◽

Ning Zhao ◽

...

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Supramolecular Hydrogel ◽

Micro Scale ◽

Triple Shape Memory

Here, we present a novel mechanical stretchable supramolecular hydrogel with a triple shape memory effect at the macro/micro scale.

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The Effect of Some Factors on Ms and Sme in Ce-TZP Ceramics

MRS Proceedings ◽

10.1557/proc-246-213 ◽

1991 ◽

Vol 246 ◽

Cited By ~ 5

Author(s):

Bohong Jiang ◽

Jinbiao Tu ◽

T.Y. Hsu ◽

Zuyao Xu ◽

Xuan Qi ◽

...

Keyword(s):

Shape Memory ◽

Intermetallic Compounds ◽

Shape Memory Effect ◽

Memory Effect ◽

Shape Recovery ◽

Tetragonal Zirconia ◽

Metallic Alloys ◽

Maximum Deflection ◽

Zirconia Ceramics ◽

Shape Memory Behaviour

As known to all,shape memory behaviour has been observed in a variety of metallic alloys. This phenomenon, however, is not only observed in that field but also in other materials recently, such as in polymers,intermetallic compounds and ceramics, especially in zirconia ceramics.Swain [1] observed the shape recovery of a bent magnesia-partiallystabilized zirconia (Mg-PSZ) bar upon heating above a certain temperature. The maximum deflection which was nearly completely recovered on heating is about 300 μm.Chen et al [2] investigated the pseudoelasticity and shape memory effect (SME) in ceria-stabilized tetragonal zirconia polycrystals (Ce- TZP) containing 12 mol% CeO2.Wang et al [3] also observed the SME in Ce-TZP containing 10 mol% CeO2,.Here we would like to introduce some of results conducted recently in our group on SHE in Ce-TZP ceramics.

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

Materials Science Forum ◽

10.4028/www.scientific.net/msf.738-739.247 ◽

2013 ◽

Vol 738-739 ◽

pp. 247-251 ◽

Cited By ~ 1

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.

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Investigation of the Kinetic of a Bainitic Reaction upon Heating in a CuAlNiMn and a CuAlNiMnFe Shape Memory Alloy

Materials Science Forum ◽

10.4028/www.scientific.net/msf.752.3 ◽

2013 ◽

Vol 752 ◽

pp. 3-9 ◽

Cited By ~ 2

Author(s):

Marton Benke ◽

Valéria Mertinger ◽

Peter Barkoczy

Keyword(s):

Solid State ◽

Kinetic Model ◽

Shape Memory Alloy ◽

Shape Memory Alloys ◽

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

One Stage ◽

Shape Memory Behaviour ◽

Memory Characteristics

The examination of solid state processes leading to the degradation of the shape memory behaviour is essential with respect to the suitability of shape memory alloys. Besides degradation processes occurring during relatively long periods of time called ageing, bainitic reactions that suddenly degrade the shape memory behaviour were also observed in many Cu-based shape memory alloys. The mechanisms and effects of the bainitic reactions on the shape memory characteristics were investigated in many Cu-based systems, but the kinetic of the reaction was not examined so far. In the present paper, an examination was carried out on a CuAlNiMn and a CuAlNiMnFe shape memory alloy to reveal what kinetic model describes the bainitic reaction occurring and thus completely destroying the shape memory effect during one stage of heating.

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Effect of Nitrogen on Shape Memory Behaviour of FE-MN-SI-CR-NI Alloys

MRS Proceedings ◽

10.1557/proc-459-357 ◽

1996 ◽

Vol 459 ◽

Author(s):

A. Ariapour ◽

D. D. Perovic ◽

A. Mclean

Keyword(s):

Shape Memory ◽

Shape Memory Effect ◽

Memory Effect ◽

Nitrogen Concentration ◽

Alloying Element ◽

Ni Alloys ◽

Dispersed Particles ◽

Structural Applications ◽

Nitrogen Alloying ◽

Shape Memory Behaviour

ABSTRACTThe composition of an Fe-Mn-Si-Cr-Ni stainless steel with shape memory effect was altered in this work in order to increase the strength of the alloy. The alloy possessed a low yield strength which is a major draw back for structural applications.Nitrogen alloying, using nitrogen pressurized melting (P=l–10 atm), was employed to introduce a nitrogen concentration of up to 0.36 wt%. The effect of nitrogen alloying on shape memory effect was studied through mechanical testing. It was found that nitrogen alloying increased the hardness; however, nitrogen as an interstitial alloying element suppressed the γ⇒ε transformation and therefore decreased the shape memory effect.Introducing small amount of Nb (e. g., 0.36 wt%) to the nitrogen containing alloys caused formation of NbN. The NbN compound was in the form of globular dispersed particles (200 nm) which increased the strength of the alloy without significantly changing the shape memory effect.

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Tensile Failure of 55-Nitinol Wire

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s0424820100113858 ◽

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.

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