Influence of heat treatment on the properties of shape memory fibers. I. Crystallinity, hydrogen bonding, and shape memory effect

2008 ◽  
Vol 109 (4) ◽  
pp. 2616-2623 ◽  
Author(s):  
Qinghao Meng ◽  
Jinlian Hu
Keyword(s):  
Heat Treatment ◽  
Hydrogen Bonding ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Memory Fibers

Effect of the Cutting Velocity and Heat Treatment on Turning Cutting Forces of an SMA Cu-Al-Be Alloys

2013 ◽  
Vol 758 ◽  
pp. 157-164
Author(s):  
Francisco Valdenor Pereira da Silva ◽  
José Paulo Vogel ◽  
Rodinei Medeiros Gomes ◽  
Tadeu Antonio de Azevedo Melo ◽  
Anna Carla Araujo ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Cutting Force ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Chip Formation ◽  
Cutting Forces ◽  
Cutting Velocity ◽  
Resultant Forces

This work studies the effect of heat treatment and cutting velocities on machining cutting forces in turning of a Cu-11.8%Al-0.55%Be shape memory alloys. The heat treatment was performed to obtain samples with austenite and martensite microstructures. Cutting force was investigated using a 3-component dynamometer in several revolutions and data were analyzed using statistic tools. It was found that the resultant forces were higher in quenched alloy due to the presence of Shape Memory Effect. Chip formation occurred in a shorter time in the sample without the Shape Memory Effect.

Effect of Tin Addition on Phase Constitution and Heat Treatment Behavior in Ti-40Ta-Sn Alloys

2004 ◽  
Vol 449-452 ◽  
pp. 1273-1276 ◽  
Author(s):  
Masahiko Ikeda ◽  
S. Komatsu ◽  
Yuichiro Nakamura ◽  
Y. Kobayashi
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Shape Recovery ◽  
Resistivity Ratio ◽  
Phase Constitution ◽  
Recovery Test ◽  
Orthorhombic Martensite ◽  
Solution Treated

Using Ti-40mass%Ta-0, -4, -8 and -12mass%Sn alloys, the effect of Sn addition on phase constitution in the solution treated and quenched state and isochronal heat treatment behavior is studied by electrical resistivity and Vickers hardness measurements and X-ray diffactometry. To confirm shape memory effect of some of these alloys, shape-recovery test was also performed. Orthorhombic martensite, ” was identified in Ti-40Sn-0 to 8Sn alloy quenched from 1173K, while phase was identified in STQed Ti-40Ta-12Sn alloy. On isochronal heat treatment, increases of resistivity at LN and resistivity ratio were observed in only 8Sn alloy, because these increases are due to reverse-transformation of ” to phase. From result of shape recovery test, shape memory effect was observed in Ti-40Ta-4 and 8Sn alloys

The Effect of Heat Treatment on the Shape Memory Effect and Superelasticity in NiMnGa Single Crystals

2017 ◽  
Vol 743 ◽  
pp. 91-94
Author(s):  
Maria Pichkaleva ◽  
Ekaterina Timofeeva ◽  
Anton Tagil'tsev ◽  
Elena Panchenko ◽  
Yuri Chumlyakov
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Single Crystals ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Thermal Hysteresis ◽  
Slow Cooling ◽  
Critical Stresses

It was shown in Ni53Mn25Ga22 single crystals that the annealing at 1273 K for 1 h followed by slow cooling, at which the (L21+γ)-structure is formed, provides the increase of crystals plasticity as compared with the brittle initial L21-single crystals. The increase of critical stresses by more than 2 times (up to σ > 150 MPa), at which the cooling/heating cycles under stress are accompanied by sample destruction, is observed. Moreover, the value of thermal hysteresis is increased by 1.5 times and the perfect curve of superelasticity is observed at T=423 K.

Heat Treatment of Ni-Ti Alloy for Improvement of Shape Memory Effect

1997 ◽  
Vol 12 (1) ◽  
pp. 107-115 ◽  
Author(s):  
K. Sadrnezhaad ◽  
F. Mashhadi ◽  
R. Sharghi
Keyword(s):  
Heat Treatment ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Ti Alloy

Generation of Smart Structures on the Basis of In Situ Configuration of Shape Memory Alloys

2008 ◽  
Vol 59 ◽  
pp. 184-189 ◽  
Author(s):  
Sven Langbein ◽  
Edwald G. Welp
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Local Heat ◽  
Local Material ◽  
Local Material Properties ◽  
Study Offer

An outstanding feature of shape memory alloys (SMAs) is their potential to produce different functional effects like thermal shape memory or superelasticity in one component. The purpose of the present study is to find a way to create a universal component with properties adjustable for various applications solely by modifying the local material properties. We refer to this process as in-situ configuration. The basis of in-situ configuration of the materials’ properties is generated by first deactivating the shape memory effect in the whole element and then local activation of the shape memory effect by use of local heat treatment. The NiTi-elements presented in this study offer various options, since they do not feature perceptible thermal shape memory or superelasticity due to a high dislocation density. Instead, to achieve a specific local function, the elements are subjected to in-situ heat treatment carried out by a local resistive heating element. There is a need to adjust the duration and intensity of the heat input in order to obtain different functional properties.

The Effect of Heat Treatment on the Shape Memory Effect of Ni-Ti Alloy Ultra-Thin Wires

2011 ◽  
Vol 332-334 ◽  
pp. 912-915
Author(s):  
Dan Zhang ◽  
Lei Xu ◽  
Rui Wang ◽  
Li Feng Xu
Keyword(s):  
Heat Treatment ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Crystal Morphology ◽  
Treatment Temperature ◽  
Ti Alloy ◽  
Thin Wires ◽  
Treatment Conditions

Various heat treatment conditions with temperature scans of 300-700 °C, and annealing time scans of 1-4 hours were adopted in the annealing of Ti-49.5at.%-Ni shape memory alloy ultra thin wires. The mechanical hysteretic curves and the crystal morphology were obtained by the tensile-recovery testing and scan electric microscopes (SEM). The result shows that the shape memory effect of Ni-Ti alloy first decline after rising with the heat treatment temperature increases. Alloy with heat treatment effect in 500°C, presents the best. Time is not a significant factor for heat treatment.

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