Crystallization of Amorphous Sputtered NiTi Shape-Memory Alloy Films

1995 ◽  
Vol 398 ◽  
Author(s):  
F.F. Gong ◽  
H.M. Shen ◽  
Y.N. Wang
Keyword(s):  
Shape Memory ◽  
Annealing Temperature ◽  
Optimum Shape ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
Initial Stage ◽  
Average Grain Size ◽  
Optimum Heat ◽  
Diffraction Patterns ◽  
Optimum Heat Treatment

ABSTRACTThe crystallization of amorphous sputtered NiTi films was investigated for selected heat treatments. From x-ray diffraction patterns, when the films were annealed below the crystallization temperature, the intensity of the broad maximum centered at 2θ = 43.5° increased with increasing the annealing temperature and time. When the films were annealed at 550°C for 0.5hr, parent B2 phase and Ni4Ti3 precipitates appeared. For annealing temperature above 700°C, the films showed embrittlement and volatilization. Therefore the optimum heat treatment for the optimum shape memory effect is found. The average grain size increased slowly in the initial stage of annealing but remained almost unchanged when the films were annealed for more than 1hr. This is because the grain boundary grooving caused by the titanium at a certain temperature volatilization seriously hinder the grain growth.

scholarly journals The Influence of Annealing Temperature on the Structure and Magnetic Properties of Nanocrystalline BiFeO3 Prepared by Sol–Gel Method

2021 ◽  
Author(s):  
T. Pikula ◽  
T. Szumiata ◽  
K. Siedliska ◽  
V. I. Mitsiuk ◽  
R. Panek ◽  
...  
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Annealing Temperature ◽  
Sol Gel ◽  
Weak Ferromagnetism ◽  
X Ray Diffraction ◽  
Gel Method ◽  
Sol Gel Method ◽  
Average Grain Size ◽  
Spin Cycloid

AbstractIn this work, BiFeO3 powders were synthesized by a sol–gel method. The influence of annealing temperature on the structure and magnetic properties of the samples has been discussed. X-ray diffraction studies showed that the purest phase was formed in the temperature range of 400 °C to 550 °C and the samples annealed at a temperature below 550 °C were of nanocrystalline character. Mössbauer spectroscopy and magnetization measurements were used as complementary methods to investigate the magnetic state of the samples. In particular, the appearance of weak ferromagnetic properties, significant growth of magnetization, and spin-glass-like behavior were observed along with the drop of average grain size. Mössbauer spectra were fitted by the model assuming cycloidal modulation of spins arrangement and properties of the spin cycloid were determined and analyzed. Most importantly, it was proved that the spin cycloid does not disappear even in the case of the samples with a particle size well below the cycloid modulation period λ = 62 nm. Furthermore, the cycloid becomes more anharmonic as the grain size decreases. The possible origination of weak ferromagnetism of the nanocrystalline samples has also been discussed.

High-energy synchrotron X-ray diffraction measurements of simple bending of pseudoelastic NiTi shape memory alloy wires

2016 ◽  
Vol 31 (2) ◽  
pp. 104-109 ◽  
Author(s):  
Baozhuo Zhang ◽  
Marcus L. Young
Keyword(s):  
Phase Transformation ◽  
Shape Memory ◽  
High Energy ◽  
Bend Angle ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Mechanical Bending ◽  
Xrd Patterns

Many technological applications of austenitic shape memory alloys (SMAs) involve cyclical mechanical loading and unloading in order to take advantage of pseudoelasticity. In this paper, we investigated the effect of mechanical bending of pseudoelastic NiTi SMA wires using high-energy synchrotron radiation X-ray diffraction (SR-XRD). Differential scanning calorimetry was performed to identify the phase transformation temperatures. Scanning electron microscopy images show that micro-cracks in compressive regions of the wire propagate with increasing bend angle, while tensile regions tend not to exhibit crack propagation. SR-XRD patterns were analyzed to study the phase transformation and investigate micromechanical properties. By observing the various diffraction peaks such as the austenite (200) and the martensite (${\bar 1}12$), (${\bar 1}03$), (${\bar 1}11$), and (101) planes, intensities and residual strain values exhibit strong anisotropy, depending upon whether the sample is in compression or tension during bending.

Deposition of TiO2 Thin Films Using Magnetron Sputtering

2011 ◽  
Vol 217-218 ◽  
pp. 1743-1746
Author(s):  
Xing Long Guo
Keyword(s):  
Electron Microscopy ◽  
Thin Films ◽  
Magnetron Sputtering ◽  
Profile Analysis ◽  
Line Profile Analysis ◽  
Analysis Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Average Grain Size ◽  
Diffraction Patterns

TiO2 with 20nm in diameter have been prepared by using magnetron sputtering technique. The structure of these powers was determined by X-ray diffraction experiments. The average grain size and particle size in these powers were measured by the line profile analysis method of X-ray diffraction patterns and by scan electron microscopy, respectively. The thin films were investigated by using XRD, SEM measurements.

scholarly journals Reducing the ordering temperature of FePt nanoparticles by Cu additive and alternate reduction method

2017 ◽  
Vol 07 (06) ◽  
pp. 1750039
Author(s):  
Fang Wang ◽  
Xiaojun Bai
Keyword(s):  
Annealing Temperature ◽  
Reduction Method ◽  
Magnetic Hysteresis ◽  
Magnetic Hysteresis Loop ◽  
Metal Salts ◽  
Fept Nanoparticles ◽  
X Ray Diffraction ◽  
X Ray ◽  
Diffraction Patterns ◽  
Cu Additive

(FePt)[Formula: see text]Cu[Formula: see text] nanoparticles were successfully prepared by alternate reduction of metal salts in aqueous medium. Detailed investigations on the correlation between the magnetic and structural properties of these nanoparticles are presented as a function of annealing temperature. Both the X-ray diffraction patterns and the magnetic hysteresis loop measurements show the existence of L10-FePt phase at a relative low annealing temperature. It is proved that the Cu additive and alternate reduction are very effective methods in reducing the ordering temperature of FePt nanoparticles.

The Structure and Shape Memory of the Hot Extruded NiTi Alloy

2016 ◽  
Vol 687 ◽  
pp. 19-24
Author(s):  
Tomasz Goryczka ◽  
Zdzisław Lekston ◽  
Jerzy Dybich ◽  
Maciej Zubko ◽  
Tadeusz Wierzchoń ◽  
...  
Keyword(s):  
Shape Memory ◽  
Shape Recovery ◽  
Cast Alloy ◽  
Niti Alloy ◽  
Hot Extrusion ◽  
Point Of View ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
Axial Texture ◽  
Texture Type

The paper presents results of structural studies of hot extruded NiTi shape memory alloy that is in the B2 phase at room temperature. Texture of the alloy was determined from the X-ray diffraction measurements. It was found that in result of 60 % sample reduction (at a cross-section of a bar formed by hot extrusion) weak axial texture - type <110>B2 was formed. The volume of the grains oriented in this way was approx. 20 %. Basing on metallographic observations it was also found that the size of the grains formed as a result of the thermomechanical treatment was uniform with the average area of 1700 μm2. This information is significant from the point of view of functional properties. Hot extruded alloy revealed presence of the reversible martensitic transformation. Its characteristic temperatures were slight higher than in as-cast alloy. Moreover, the extruded NiTi alloy showed 100 % of the shape recovery.

scholarly journals NiTi shape memory alloy: physical and tribological characterization

2018 ◽  
Vol 27 (1-2) ◽  
Author(s):  
Pardeep Sharma
Keyword(s):  
Shape Memory Alloy ◽  
Shape Memory ◽  
Wear Behavior ◽  
Research Work ◽  
Constant Load ◽  
Binder Content ◽  
Niti Shape Memory Alloy ◽  
X Ray Diffraction ◽  
The Coefficient Of Friction ◽  
Tribological Characterization

AbstractThe current research work focuses on the mechanical and tribological behavior of an NiTi shape memory alloy (SMA) processed with the help of powder metallurgy. SMAs have found applications in the medical, space and aerospace industries with usage in the manufacturing of microelectromechanicals (MEMS) and as actuators in the electronic industry. The wear behavior of a material greatly affects its performance. The wear behavior of an SMA can be determined with the help of the dry abrasion test. The increase in binder content and rotational speed at a constant load increases the wear rate of SMA alloys. The coefficient of friction decreases with the usage of alloys. A decrease in density has been found, as well as porosity, with the increasing content of binder in the alloy. Density decreases from 6.7 to 5.1 g/cm3 while porosity decreases from 57 to 23% with increased binder content. Scanning electron microscopy (SEM) and X-ray diffraction has been used for the investigation of surface morphology and phases present in the alloy.

scholarly journals Structure of tantalum coatings on NiTi substrate deposited by magnetron sputtering

2022 ◽  
Vol 2155 (1) ◽  
pp. 012013
Author(s):  
A S Dikov ◽  
A S Larionov ◽  
E A Zhakanbayev ◽  
L A Dikova ◽  
A Zh Sanssyzbayeva ◽  
...  
Keyword(s):  
Shape Memory ◽  
Phase State ◽  
Structural Phase ◽  
Interplanar Distance ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Structural Phase State ◽  
Initial Stage ◽  
Coating Formation ◽  
Tantalum Coatings

Abstract The paper provides the results of studies of the structural-phase state of tantalum coatings prepared by magnetron deposition. The coatings were deposited on substrates made of titanium nickelide with a shape memory. The NiTi temperature during coating deposition did not exceed 100 °C. The structural-phase state of Ta was determined by X-ray diffraction at different stages of coating formation. It has been shown that at the initial stage of deposition, two-phase coatings (α- and β-Ta) are formed. The synthesis of the coating from Ta leads to the growth of interplanar distance of the B2 austenite phase in the crystallographic direction (100). The growth of interplanar spacing is caused by formation of microstresses during interaction with incident tantalum ions. The lattice parameters of the B19 ‘phase, responsible for appearance of the shape memory effect, do not change during deposition of the tantalum coating.

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