Shape Memory Thin Films of the System Ti- (Ni-Pd-Cu)

1996 ◽  
Vol 459 ◽  
Author(s):  
E. Quandt ◽  
H. Holleck
Keyword(s):  
Thin Films ◽  
Differential Scanning Calorimetry ◽  
Shape Memory ◽  
Scanning Calorimetry ◽  
Free Standing ◽  
Transformation Temperatures ◽  
Resistivity Measurements ◽  
Cu Substitution ◽  
Transformation Hysteresis ◽  
And Training

ABSTRACTFree-standing shape memory thin films of the system Ti-Ni-Pd-Cu exhibiting the two-way-effect have been fabricated by d.c. magnetron sputtering onto unheated substrates followed by annealing and training processes. Their transformation temperatures were investigated by differential scanning calorimetry and electrical resistivity measurements. By the Ni-Pd substitution the transformation temperatures (austenite/martinsite finish temperature; Af/Mf) could be varied between 32°C/-38°C for the binary TiNi films to 570°C/498°C for the binary TiPd films. By the Ni-Cu substitution the transformation hysteresis (Af/Mf) could be reduced from 70°C for the binary film to 20°C for films with 10 at % Cu. A similar behavior was observed for TiNiPdCu films.

Effects of Stress Induced by the Underlying Layers on the Micro-Structures and Characteristic Phase Transformation Temperatures of Sputtered TiNi Thin Films

2001 ◽  
Author(s):  
Rong Xin Wang ◽  
Yitshak Zohar ◽  
Man Wong
Keyword(s):  
Thin Films ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Free Standing ◽  
Transformation Temperatures ◽  
Lattice Constants ◽  
Induced Stress ◽  
Titanium Nickel ◽  
Micro Structures

Abstract The micro-structures and the phase transformation temperatures of sputtered titanium-nickel (TiNi) thin films, both free-standing and attached on different underlying multi-layer substrates have been studied. Differences in the micro-structures, such as the lattice constants and the relative concentrations of TiNi, Ti2Ni and TiNi3 phases, were observed (1) among the free-standing and the attached films, (2) among the films attached on different underlying multi-layers and (3) among films with different relative orders of aging and release. Not surprisingly, the corresponding phase transformation temperatures are also different. It is proposed that both substrate- and process-induced stress significantly affect the micro-structures, hence the phase transformation characteristics, of the resulting shape-memory alloy thin films.

Effect of the Cooling Time in Annealing at 350°C on the Phase Transformation Temperatures of a Ni55Ti45 wt. Alloy

2015 ◽  
Vol 1120-1121 ◽  
pp. 958-961
Author(s):  
Tadeu Castro da Silva ◽  
Daniel Monteiro Rosa ◽  
Edson Paulo da Silva
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
Cooling Time ◽  
Phase Transformation Temperature ◽  
Thermal Treatments ◽  
Heating Rates ◽  
Scanning Calorimetry ◽  
Transformation Temperatures

When submitted to annealing thermal treatments Shape Memory Alloys have their phase transformation temperatures effected. The aim of the present work is to investigate the effects of cooling time in the phase transformation temperatures of Ni55Ti45in w.t. % alloy annealed at 350°C. Samples of this alloy were maintained at 350°C for one hour and then cooled in the same furnace for 10 minutes, 1 hour and 24 hours. The phase transformation temperatures were measured by means of Differential Scanning Calorimetry (DSC) at cooling and heating rates of 20°C/min. The results show that the annealing at 350°C changed the phase transformation up to 54%. For 10 minutes cooling time the Mftemperature increase from 15,65°C to 24,1°C. For the others cooling times the phase transformation temperature did not change significantly. Therefore, the cooling time for the annealing at 350°C did not effect the phase transformation temperatures of the Ni45Ti55in wt % shape memory alloy.

Influence of Thermomechanical Treatment on Transformation Temperatures of Cu-Al-Ni Shape Memory Alloys

2008 ◽  
Vol 59 ◽  
pp. 92-100
Author(s):  
Ana Cris R. Veloso ◽  
Rodinei Medeiros Gomes ◽  
Dagoberto Brandao Santos ◽  
I.C.E.G. Lima ◽  
Severino Jackson Guedes de Lima ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Differential Scanning Calorimetry ◽  
Shape Memory Alloys ◽  
Shape Memory ◽  
Thermomechanical Treatment ◽  
Hot Rolling ◽  
Rolling Process ◽  
Induction Melting ◽  
Scanning Calorimetry ◽  
Transformation Temperatures

In this study Cu-13.8Al alloys with 3.0% and 4.0% (wt%) of nickel were obtained by induction melting. The effect of homogenization heat treatment and hot rolling on the transformation temperatures of these alloys was investigated by differential scanning calorimetry. It was observed that the transformation temperatures increase with long homogenization times, and also by hot rolling, and this displacement is smaller for alloys with 4.0% of nickel. In both alloys in the quenched state, the reversion reaction is characterized by the appearance of multiple peaks attributed to the presence of martensites 2H and 18R. The influence of the rolling process must be associated with the loss of Ni and Al during the process.

Effect of Electroplastic Deformation on Martensitic Transformation in Coarse Grained and Ultrafine Grained Ni-Ti Shape Memory Alloy

2008 ◽  
Vol 584-586 ◽  
pp. 127-132 ◽  
Author(s):  
Anastasia E. Sergeeva ◽  
Daria Setman ◽  
Michael Zehetbauer ◽  
Sergey Prokoshkin ◽  
Vladimir V. Stolyarov
Keyword(s):  
Differential Scanning Calorimetry ◽  
Martensitic Transformation ◽  
Shape Memory Alloy ◽  
Cold Rolling ◽  
Shape Memory ◽  
Coarse Grained ◽  
Scanning Calorimetry ◽  
Structure Relaxation ◽  
Differential Scanning Calorimetry Method ◽  
Ultrafine Grained

The aim of this paper is the investigation of electroplastic deformation (EPD) and subsequent annealing influence on martensitic transformation in the shape memory Ni50.7Ti49.3 alloy. Using differential scanning calorimetry method it was shown that EPD at the low strain stimulates structure relaxation and recovers martensitic transformation in cooling, which is usually suppressed by cold rolling.

scholarly journals Nanocrystal, phase transformation and microstructure of Ni50Ti50 shape memory alloy

2018 ◽  
Vol 24 (02) ◽  
pp. 22-25
Author(s):  
Dovchinvanchig M ◽  
Chunwang Zhao
Keyword(s):  
Differential Scanning Calorimetry ◽  
Phase Transformation ◽  
Shape Memory Alloy ◽  
Shape Memory ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
One Step ◽  
Niti Matrix ◽  
Electronic Microscope

The nanocrystal, phase transformation and microstructure behavior of Ni50Ti50 shape memory alloy was investigated by scanning electronic microscope, X-ray diffraction and differential scanning calorimetry. The results showed that the microstructure of Ni-Ti binary alloy consists of the NiTi2 phase and the NiTi matrix phase. One-step phase transformation was observed alloy.

Fabrication of a novel laser-processed NiTi shape memory microgripper with enhanced thermomechanical functionality

2012 ◽  
Vol 24 (8) ◽  
pp. 984-990 ◽  
Author(s):  
Matthew Daly ◽  
Andrew Pequegnat ◽  
Yunhong N Zhou ◽  
Mohammad I Khan
Keyword(s):  
Shape Memory ◽  
Processing Technique ◽  
Thermomechanical Properties ◽  
Nickel Titanium ◽  
Testing Methods ◽  
Scanning Calorimetry ◽  
Resistivity Measurements ◽  
Processed Material ◽  
Significant Research

The thermomechanical properties of nickel-titanium shape memory alloys have sparked significant research efforts seeking to exploit their exotic capabilities. Until recently, the performance capabilities of nickel-titanium devices have been inhibited by the retention of only one thermomechanical response. In this article, the application of a novel laser-processing technique is demonstrated to create a monolithic self-positioning nickel-titanium shape memory microgripper. Device actuation and gripping maneuvers were achieved by thermally activating processed material regions which possessed unique phase transformation onset temperatures and thermomechanical recovery characteristics. The existence of each thermomechanical material domain was confirmed through differential scanning calorimetry analysis. Independent thermomechanical recoveries of each embedded shape memory were captured using tensile testing methods. Deployment of each embedded shape memory was achieved using resistive heating, and in situ resistivity measurements were used to monitor progressive phase transformations.

Novel shape-memory polyurethane fibers for textile applications

2018 ◽  
Vol 89 (6) ◽  
pp. 1027-1037 ◽  
Author(s):  
Míriam Sáenz-Pérez ◽  
Tariq Bashir ◽  
José Manuel Laza ◽  
Jorge García-Barrasa ◽  
José Luis Vilas ◽  
...  
Keyword(s):  
Differential Scanning Calorimetry ◽  
Shape Memory ◽  
Tensile Testing ◽  
Melt Spinning ◽  
Mechanical Analysis ◽  
Knitted Fabric ◽  
Scanning Calorimetry ◽  
Moisture Management ◽  
Potential Applications ◽  
Shape Memory Polyurethane

In this work, thermoresponsive shape-memory polyurethane (SMPU) fibers were produced by melt spinning from different SMPU pellets. Afterwards, the knitted fabric samples were prepared by the obtained fibers. Some of the SMPUs used were synthesized previously in our laboratory whereas a commercial one, named DIAPLEX MM4520, was also evaluated in order to carry out comparative studies. All the SMPUs were characterized by different techniques, such as thermogravimetric analysis, differential scanning calorimetry, dynamic mechanical analysis and tensile testing. Moreover, the shape-memory capabilities of the fabrics were measured by thermo-mechanical analysis. The obtained results show that the synthesized SMPUs could be attractive candidates for potential applications such as breathable fabrics or moisture-management textiles.

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