Classification and Characterization of the Shape Memory Binary Alloys

2006 ◽  
Vol 980 ◽  
Author(s):  
Mitsuo Notomi ◽  
Krystyn J Van Vliet ◽  
Sidney Yip
Keyword(s):  
Crystal Structure ◽  
Shape Memory ◽  
Shape Recovery ◽  
Major Element ◽  
Binary Alloys ◽  
Major Elements ◽  
The Other ◽  
Atomic Composition ◽  
Group 5

AbstractAll shape memory binary alloys (SMBA) that exhibit not only perfect shape recovery but also partial shape recovery were reviewed and classified into three groups, B2, A2 and A1 type, according to the parent phases. There are the thirteen, six and eleven alloys belonging to B2, A2 and A1 type, respectively. In the group of B2 type SMBA the alloys are divided into two categories due to the combination of the elements. Over A1 and A2 type SMBA the atomic composition of one element is larger than the other so the larger one is called a major element. The major elements, Ti, U, Fe, and Cu, of A2 type SMBA do not belong to the group 5 and 6 in which the elements have a typical BCC (A2) crystal structure. In the A1 type SMBA there are four major elements, Mn, Fe, Co, and In and the SMBA except for In-based SMBA have ferromagnetic or antiferromagnetic natures. The shape memory effect (SME) for A1 (FCC) type SMBA might need the magnetic properties.

scholarly journals Mineralogical and Fluid Inclusions Study of Epithermal Type Veins Intruding the Volcanic Rocks of the Kornofolia Area, Evros, NE Greece.

2019 ◽  
Vol 55 (1) ◽  
pp. 202
Author(s):  
Foteini Aravani ◽  
Lambrini Papadopoulou ◽  
Vasileios Melfos ◽  
Triantafillos Soldatos ◽  
Triantafillia Zorba ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Fluid Inclusion ◽  
Hydrothermal Alteration ◽  
Fluid Inclusions ◽  
Volcanic Rocks ◽  
The Other ◽  
Calc Alkaline ◽  
Ft Ir ◽  
Host Rocks

The volcanic rocks of Kornofolia area, Evros, host a number of epithermal-type veins. The host rocks are Oligocene calc-alkaline andesites to rhyo-dacites. The andesites form hydrothermal breccias and show hydrothermal alteration. The veins comprise mainly silica polymorphs such as quartz, chalcedony and three types of opal (milky white, transparent and green). Amethyst also forms in veins at the same area. Apart from the silica polymorphs, the veins are accompanied by calcite and zeolites. The main aim of this study is the characterization of the silica polymorphs. Using FT-IR analyses, variations in the crystal structure of the three opals were recognized. The green opal is found to be more amorphous than the other two types. Fluid-inclusion measurements were performed in calcite and were compared with amethyst from previous studies. The Th is between 121-175 °C and the Te between -22.9 and -22.4 °C. The salinities range from 0.9 to 4.5 wt % NaCl equiv.

Characterization of Creeping and Shape Memory Effect in Laser Sintered Thermoplastic Polyurethane

2016 ◽  
Vol 16 (4) ◽  
Author(s):  
Shangqin Yuan ◽  
Jiaming Bai ◽  
Chee Kai Chua ◽  
Kun Zhou ◽  
Jun Wei
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Thermoplastic Polyurethane ◽  
Selective Laser Sintering ◽  
Thermal Transitions ◽  
Temperature Dependent ◽  
Shape Memory Effects ◽  
Viscoelastic Behaviors ◽  
High Flexibility

Thermoplastic polyurethane (TPU) powders were successfully processed in a selective laser sintering (SLS) system. The laser-sintered polyurethane products with viscoelastic behaviors exhibit high flexibility and elongation at break at room temperature. Moreover, the creeping and the thermoresponsive shape-memory effects (SME) were also characterized. The influences of the time-temperature relevant parameters on the shape-fixity and shape-recovery ratios were investigated quantitatively. The creeping and SME were time–temperature dependent phenomena, and the shape recovery mechanism is associated to the microsegments thermal transitions within the polymer matrix.

Shape Recovery and ε - γ Transformation in Fe29Mn7Si5Cr SMA

2008 ◽  
Vol 59 ◽  
pp. 86-91 ◽  
Author(s):  
Nele Van Caenegem ◽  
Kim Verbeken ◽  
Roumen H. Petrov ◽  
N.M. van der Pers ◽  
Yvan Houbaert
Keyword(s):  
Martensitic Transformation ◽  
Shape Memory ◽  
Shape Recovery ◽  
Electron Backscatter Diffraction ◽  
X Ray Diffraction ◽  
X Ray ◽  
Electron Backscatter ◽  
Shape Memory Behaviour ◽  
Backscatter Diffraction

The shape memory behaviour of a Fe29Mn7Si5Cr based alloy has been investigated. Characterization of the martensitic transformation and the different structural constituents was performed using optical microscopy, X-ray diffraction (XRD) methods and electron backscatter diffraction (EBSD). The transformation temperatures and the shape recovery were determined by dilatometry on prestrained samples.

Shape Memory Properties of Ti-Ni Shape Memory Alloy / Shape Memory Polymer Composites Using Additive Manufacturing

2021 ◽  
Vol 1016 ◽  
pp. 697-701
Author(s):  
Kazuhiro Kitamura
Keyword(s):  
Shape Memory ◽  
Transformation Temperature ◽  
Shape Recovery ◽  
Shape Memory Polymer ◽  
Shape Memory Polymers ◽  
The Other ◽  
3D Printer ◽  
Shape Memory Material ◽  
Polymer Resin ◽  
Shape Memory Properties

Shape memory alloys (SMAs) have the disadvantage that cooling is difficult and the actuating speed during cooling is slow. To resolve this problem, shape memory material actuators that operate only with heating is required. SMAs are characterized by a low apparent Young's modulus below the transformation temperature and a strong shape recovery force above the reverse transformation temperature. Alternatively, shape memory polymers (SMPs) have two properties: shape fixability and shape recovery. The SMPs are hardened below the glass transition (Tg) temperature and the material is recovered to memorized shape above the Tg temperature. The other hand, 3D printer is a machine that can directly output a 3D-designed product designed by a computer in 3D, and molded materials such as polymer, resin, metal, and ceramics. In this research, we developed the SMC of SMA wire and SMP sheet using adhesive that develops actuates into two shapes only by heating.

High-Temperature Shape Memory Effect of Ti-(Pt,Ir)

2007 ◽  
Vol 539-543 ◽  
pp. 3273-3278 ◽  
Author(s):  
Yoko Yamabe-Mitarai ◽  
Toru Hara ◽  
Seiji Miura ◽  
Hideki Hosoda
Keyword(s):  
Thermal Expansion ◽  
High Temperature ◽  
Shape Memory ◽  
Compression Test ◽  
Shape Recovery ◽  
The Other ◽  
Martensitic Transformation Temperature ◽  
Testing Methods ◽  
Thermal Expansion Measurement ◽  
Ternary Compounds

Shape recovery and superelasticity of Ti-50at%Pt and Ti-50at%(Pt, Ir), whose martensitic transformation temperature are above 1273 K, were investigated by thermal expansion measurement in dilatometer and loading-unloading compression test. The shape recovery was found in all compounds in at least one of the testing methods. The highest shape recovery, about 4% was found in Ti-25Pt-25Ir using loading-unloading compression test. On the other hand, superelasticity was found in only ternary compounds. Larger superelasticity was observed in ternary compounds with higher Ir contents. Potential of Ti-50Pt and Ti-50(Pt, Ir) as high-temperature shape memory alloys is discussed.

Effects of the [OC6F5] moiety upon structural geometry: crystal structures of half-sandwich tantalum(V) aryloxide complexes from reaction of Cp*Ta(N t Bu)(CH2 R)2 with pentafluorophenol

2011 ◽  
Vol 67 (5) ◽  
pp. 416-424 ◽  
Author(s):  
Jacqueline M. Cole ◽  
Michael C. W. Chan ◽  
Vernon C. Gibson ◽  
Judith A. K. Howard
Keyword(s):  
Crystal Structure ◽  
Structural Characterization ◽  
Twist Angle ◽  
The Other ◽  
Structural Geometry ◽  
Factors Affecting ◽  
Imido Complexes ◽  
Half Sandwich ◽  
Oxide Derivative

The synthesis, chemical and structural characterization of a series of pentamethylcyclopentadienyl (Cp*) tantalum imido complexes and aryloxide derivatives are presented. Specifically, the imido complexes Cp*Ta(N t Bu)(CH2 R)2, where R = Ph [dibenzyl(tert-butylamido) (η5-pentamethylcyclopentadienyl)tantalum(IV) (1)], Me2Ph [tert-butylamido)bis(2-methyl-2-phenylpropyl) (η5-pentamethylcyclopentadienyl)tantalum(IV) (2)], CMe3 [(tert-butylamido)bis(2,2-dimethylpropyl) (η5-pentamethylcyclopentadienyl)tantalum(IV) (3)], are reported. The crystal structure of (3) reveals α-agostic interactions with the Ta atom. The resulting increase in the tantalum core coordination improves electronic stability. As such it does not react with pentafluorophenol, in contrast to the other two reported imido complexes [(1) and (2)]. Addition of C6F5OH to (1) yields a dimeric aryl-oxide derivative, [Cp*Ta(CH2Ph)(OC6H5)(μ-O)]2 [di-μ-oxido-bis[benzyl(pentafluorophenolato) (η5-pentamethylcyclopentadienyl)tantalum(V)] (4)]. Its crystal structure reveals long Ta—O(C6H5) bonds but short oxo-bridging Ta—O bonds. This is explained by accounting for the fierce electronic competition for the vacant d π orbitals of the electrophilic TaV centre. Steric congestion around each metal is alleviated by a large twist angle (77.1°) between the benzyl and pentafluorophenyl ligands and the ordering of each of these groups into stacked pairs. The imido complex (2) reacts with C6F5OH to produce a mixture of Cp*Ta(OC6F5)4 [tetrakis(pentafluorophenolato)(η5-pentamethylcyclopentadienyl)tantalum(V) (5)] and [Cp*Ta(OC6F5)2(μ-O)]2 [di-μ-oxido-bis[bis(pentafluorophenolato)(η5-pentamethylcyclopentadienyl)tantalum(V)] (6)]. Steric congestion is offset in both cases by the twisting of its pentafluorophenyl ligands. Particularly strong electronic competition for the empty d π metal orbitals in (6) is reflected in its bond geometry, and owes itself to the more numerous electron-withdrawing pentafluorophenyl ligands. The balance of steric and electronic factors affecting the reactivity of Cp* tantalum imido based complexes with pentafluorophenol is therefore addressed.

Synthesis and characterization of durene-capped porphyrins and the crystal structure of a hemin derivative

1986 ◽  
Vol 64 (1) ◽  
pp. 208-212 ◽  
Author(s):  
Shantha David ◽  
David Dolphin ◽  
Brian R. James ◽  
John B. Paine III ◽  
Tilak P. Wijesekera ◽  
...  
Keyword(s):  
Crystal Structure ◽  
Phenyl Group ◽  
The Other ◽  
Synthesis And Characterization ◽  
X Ray ◽  
Hydrophobic Cavity ◽  
Pyramidal Geometry ◽  
Porphyrin Core ◽  
Square Pyramidal Geometry

Sterically hindered porphyrins having a fully hydrophobic cavity have been prepared. The cavity is capped with a 2,3,5,6-tetramethylbenzene moiety containing at the 1,4-positions methylene —(CH2)n— chains (n = 4, 5, 7) bonded at trans pyrrole rings of a porphyrin that is alkylated with methyl or ethyl groups at the other β-pyrrolic positions. The iron(III) chloride derivative of the 4,4-durene-capped base has been obtained as single crystals, and subjected to X-ray structural analysis. The typical high spin, square pyramidal geometry of five-coordinate hemin chlorides is maintained; the porphyrin core is strongly distorted and there is no interaction between the phenyl group of the strap and the iron.

Tension-Compression Asymmetry of Solid, Shape Recovered “Bulk” Nitinol

2009 ◽  
Author(s):  
Matthew Fonte ◽  
Anil Saigal
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Experimental Studies ◽  
Small Diameter ◽  
Thin Wall ◽  
Solid Bulk ◽  
Novel Devices ◽  
Deformation Modes ◽  
Tension Compression Asymmetry

As the shape memory material Nitinol (55% Nickel – 45% Titanium alloy) emerges to find more and more applications in engineered products, understanding the effects of material processing becomes increasingly important. Its mechanical behavior is highly non-linear and is strongly dependent on alloy composition, heat treatment history and mechanical work. Published Nitinol literature is almost exclusively related to processing and testing of thin wall, very small diameter tubing and wire devices, usually exhibiting superelastic characteristics. In strain-controlled tension-compression testing of pseudoelastic Nitinol shape memory wires, compression recovery forces were found to be markedly higher than tension forces. However, most experimental studies of the thermomechanical behavior of Nitinol (NiTi) to date have been conducted in uniaxial tension on wire devices. There is a dearth of information in the literature regarding the compression recovery of solid blocks of Nitinol. Questions exist on whether or not solid, “bulk” Nitinol products when deformed in compression will exhibit shape recovery characteristics? The potential for shape recovery of compressed solid blocks of Nitinol products, which could have large stress-strain outputs, can enable the design of novel devices in many industries. The motivation for this research is to provide the first characterization of the shape recovery effects of “bulk” Nitinol material under compressive deformation modes versus the often practiced and well understood tensile loading of wire and thin wall tubing.

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