Phase Transformations in Amorphous Bilayer Ribbons

2011 ◽  
Vol 172-174 ◽  
pp. 953-958 ◽  
Author(s):  
Peter Svec ◽  
Peter Svec Sr. ◽  
Igor Matko ◽  
Ivan Skorvánek ◽  
Jozef Kováč ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Phase Transformations ◽  
Amorphous State ◽  
Single Layer ◽  
Amorphous Structure ◽  
Rapid Quenching ◽  
Layer Interface ◽  
Different Temperatures

Bilayer ribbons were prepared by rapid quenching from the melt using a double-nozzle technique. The composition of the layers was selected from the Fe/Co-Si-B and Fe-Cu-Nb-Si-B systems, respectively. Ribbons with typical thickness of 45-50 microns and width of 6 mm and 10 mm exhibited amorphous structure of both layers in as-quenched state. Temperature dependencies of electrical resistivity, dilatation and magnetization have been investigated in the amorphous state and during crystallization of both layers, which take place at different temperatures. The results combined with investigation of the structures formed in each layer and at the layer interface were compared to those of single-layer ribbons having the compositions of each layer, respectively.

Structure and Properties of the Melt-Spun Fe41Ni39P10Si5B5 Alloy Heat Treated at Elevated Temperatures

2010 ◽  
Vol 163 ◽  
pp. 101-105
Author(s):  
Krzysztof Ziewiec ◽  
Krystian Prusik
Keyword(s):  
Glass Transition ◽  
Phase Transformations ◽  
Storage Modulus ◽  
Elevated Temperatures ◽  
Amorphous Structure ◽  
Transmission Electron ◽  
Melt Spun ◽  
Different Temperatures ◽  
Alloy Heat ◽  
Two Stages

The aim of the work was to provide information on structure development and change of properties at elevated temperatures in Fe41Ni39P10Si5B5 amorphous alloy. The alloy was characterized by X-ray diffraction. The changes of properties were characterized with use of dynamic mechanical thermal analysis (DMTA) and the resistivity measurements at elevated temperatures. The microstructure of the melt spun ribbon was investigated with use of transmission electron microscope (TEM) at different stages of phase transformations after heating to different temperatures. The initially amorphous structure undergoes phase transformations due to glass transition and crystallization of the alloy. The appearance of glass transition region results in decrease of storage modulus and in a reversible change of temperature coefficient of resistivity (TCR). The phases are characterized with use of TEM. The crystallization was found to have the two stages. Formation of bcc crystals and Ni12P5 is followed by transformation of the products into fcc crystals and Ni3P. Temporary changes of the storage modulus and elongation of the sample suggest formation of hard phases during crystallization.

Phase Transformations «Amorphization ↔ Crystallization» In Metallic Materials Induced by Severe Plastic Deformation

2018 ◽  
Vol 54 (1) ◽  
pp. 93-105 ◽  
Author(s):  
R.V. Sundeev ◽  
A. M. Glezer ◽  
A. V. Shalimova
Keyword(s):  
Plastic Deformation ◽  
Severe Plastic Deformation ◽  
Phase Transformations ◽  
High Pressure Torsion ◽  
Amorphous State ◽  
Structural Features ◽  
Nanocrystalline State ◽  
Basic Principles ◽  
Phase Cycling ◽  
Different Temperatures

Abstract In this review we are considered systematically the phenomenon of deformation-induced phase transformations from crystalline intermetallic compounds and complex phases to amorphous state and vice versa phase transformations from amorphous state to crystalline one upon severe plastic deformation at different temperatures. The nature and structural features of these transitions essentially for high pressure torsion deformation are analyzed in the frame of basic principles of nonequilibrium thermodynamics. The effects of phase cycling and a stationary amorphous - nanocrystalline state formation at significant deformations is discussed in details.

scholarly journals XVI Международная конференция "Термоэлектрики и их применения --- 2018" (ISCTA 2018), Санкт-Петербург, 8-12 октября 2018 г. Термоэлектрические свойства лент In-=SUB=-0.2-=/SUB=-Ce-=SUB=-0.1-=/SUB=-Co-=SUB=-4-=/SUB=-Sb-=SUB=-12.3-=/SUB=-, полученных методом быстрой закалки

2019 ◽  
Vol 53 (5) ◽  
pp. 587
Author(s):  
С.В. Новиков ◽  
А.Т. Бурков ◽  
Х. Танг ◽  
Я. Ян ◽  
А.С. Орехов
Keyword(s):  
Electrical Resistivity ◽  
Thermoelectric Properties ◽  
Temperature Stability ◽  
Amorphous Structure ◽  
Rapid Quenching ◽  
Initial Material ◽  
Stability Range ◽  
Plasma Sintering ◽  
Spark Plasma ◽  
First Time

The article presents experimental results on thermoelectric properties of In0.2Ce0.1Co4Sb12.3 alloy, prepared by rapid quenching technique. The initial material, typically in the form of thin ribbons, has quasi-amorphous structure. Usually, the ribbons are crashed to powder with subsequent compaction by hot-pressing or spark plasma sintering techniques. However, the thermoelectric properties of as-prepared ribbons have been unknown. In this work the thermopower and the electrical resistivity of In0.2Ce0.1Co4Sb12.3 ribbons are studied for the first time at temperatures from 100 K to 750 K. Temperature stability range of the quasi-amorphous structure, and the crystallization kinetics were investigated.

Defect Agglomeration and Electron-Beam-Induced Local-Phase Transformations in Single-Layer MoTe2

2021 ◽  
Author(s):  
Janis Köster ◽  
Mahdi Ghorbani-Asl ◽  
Hannu-Pekka Komsa ◽  
Tibor Lehnert ◽  
Silvan Kretschmer ◽  
...  
Keyword(s):  
Electron Beam ◽  
Phase Transformations ◽  
Single Layer ◽  
Local Phase

Preparation and Characterization of NTC NiMn2O4-La1-xCaxMnO3 (0≤x≤0.3) Composite Ceramics

2013 ◽  
Vol 716 ◽  
pp. 78-83 ◽  
Author(s):  
Hui Min Zhang ◽  
Fang Guan ◽  
Ai Min Chang ◽  
Li Jun Zhao
Keyword(s):  
Electrical Resistivity ◽  
Perovskite Structure ◽  
Spinel Structure ◽  
Thermal Constant ◽  
Inrush Current ◽  
Composite Ceramics ◽  
Sem Images ◽  
Conventional Solid State Reaction ◽  
Different Temperatures ◽  
Xrd Patterns

Composite ceramics made of spinel structure NiMn2O4 and CaO-doped perovskite structure LaMnO3 were prepared by a conventional solid state reaction and sintered at different temperatures. The XRD patterns have shown that the major phases presented in the sintered samples are NiMn2O4 compounds with the spinel structure, La1-xCaxMnO3 with the perovskite structure and NiO with a monoclinic structure. SEM images show that the density and grain size of the composite ceramics increases with sintered temperature increasing. The electrical resistivity of the composite ceramics at 25°C is found to change significantly depending on the CaO content, while the thermal constant B is still reasonably large in the range of 2400 to 3000 K. For the composition x = 0.1, the composite with a low electrical resistivity (ρ25°C=4.46Ω·cm) and moderate B value (B25/50=2762K) was obtained. These composites could be applied as potential candidates for NTC thermistors in the suppression of the inrush current.

Characteristics of FeCuAl Powder Compacts Formed through Uniaxial Die Compaction Route

2017 ◽  
Vol 264 ◽  
pp. 103-106 ◽  
Author(s):  
M.M. Rahman ◽  
M.A. Ismail ◽  
H. Y. Rahman
Keyword(s):  
Electrical Resistivity ◽  
Relative Density ◽  
Bending Strength ◽  
Axial Loading ◽  
Homogeneous Distribution ◽  
Volumetric Expansion ◽  
Different Temperatures ◽  
Die Compaction ◽  
Powder Compacts ◽  
Interconnected Pores

This paper presents the development of FeCuAl powder compacts through uniaxial die compaction process. Iron powder ASC 100.29 was mechanically mixed with other elemental powders, i.e., copper (Cu), and aluminum (Al) for 30 minutes at a rotation of 30 rpm. The feedstock was subsequently shaped at three different temperatures, i.e., 30°C, 150°C, and 200°C through simultaneous upward and downward axial loading of 325 MPa. The as-pressed samples termed as green compacts were then sintered in argon gas fired furnace at 800°C for three different holding times, i.e., 30, 60, and 90 min at a rate of 10°C/min. The sintered samples were characterized for their relative density, electrical resistivity, and bending strength. The microstructure of the sintered samples was also evaluated through scanning electron microscopy (SEM). The results revealed that the sample formed at 150°C and sintered for 30 min obtained the best final characteristics, i.e., higher relative density, lower volumetric expansion and electrical resistivity, and higher bending strength. Microstructure evaluation also revealed that the sample formed at 150°C and sintered for 30 min obtained more homogeneous distribution of grains and less interconnected pores compared to the other samples.

scholarly journals Interfacial reactions of Co/Si0.76Ge0.24 and Co(Si0.76Ge0.24)/Si0.76Ge0.24 by pulsed KrF laser annealing

1999 ◽  
Vol 14 (8) ◽  
pp. 3433-3438 ◽  
Author(s):  
Jian-Shing Luo ◽  
Yu-Lin Hang ◽  
Wen-Tai Lin ◽  
C. Y. Chang ◽  
P. S. Shih
Keyword(s):  
Energy Density ◽  
Laser Annealing ◽  
Strain Relaxation ◽  
Single Layer ◽  
Amorphous Structure ◽  
Pulse Number ◽  
Interfacial Reactions ◽  
Constitutional Supercooling ◽  
Depth Direction ◽  
Krf Laser

Interfacial reactions of Co/Si0.76Ge0.24 and Co(Si0.76Ge0.24)/Si0.76Ge0.24 by pulsed KrF laser annealing as a function of energy density and pulse number were studied. For the Co/Si0.76Ge0.24 samples annealed at an energy density of 0.2–0.6 J/cm2, three germanosilicide layers, i.e., amorphous structure and/or nanocrystal, Co(Si1−xGex), and Co(Si1−xGex)2, were successively formed along the film-depth direction. At 0.3 J/cm2 Ge segregated to the underlying Si0.76Ge0.24 film, inducing strain relaxation in the residual Si0.76Ge0.24 film. At 0.8 J/cm2 the reacted region was mostly transformed to a single layer of Co(Si1−xGex)2, whereas Ge further diffused to the Si substrate. At 1.0 J/cm2, constitutional supercooling appeared. Even the Co(Si0.76Ge0.24) film used as the starting material for laser annealing could not prevent the occurrence of constitutional supercooling at energy densities >1.6 J/cm2. The energy densities at which Co(Si1−xGex) transformation to Co(Si1−xGex)2, Ge segregation to the underlying Si, and constitutional supercooling occurred were higher for the Co(Si0.76Ge0.24)/ Si0.76Ge0.24 system than for the Co/Si0.76Ge0.24 system. Higher energy density and/or pulse number enhanced the growth of Co(Si1−xGex)2 film. In the present study, the Co/Si0.76Ge0.24 samples subjected to annealing at 0.2 J/cm2 for 20 pulses produced a smooth Co(Si0.76Ge0.24)2 film without inducing Ge segregation out of the germanosilicide and strain relaxation in the unreacted Si0.76Ge0.24 film.

In situ characterizations of phase transformations kinetics in the Ti17 titanium alloy by electrical resistivity and high temperature synchrotron X-ray diffraction

2008 ◽  
Vol 476 (1-2) ◽  
pp. 60-68 ◽  
Author(s):  
Fabien Bruneseaux ◽  
Elisabeth Aeby-Gautier ◽  
Guillaume Geandier ◽  
Julien Da Costa Teixeira ◽  
Benoît Appolaire ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Titanium Alloy ◽  
High Temperature ◽  
Phase Transformations ◽  
X Ray Diffraction ◽  
X Ray

Optimization of the Coating Technology for Super-Porous Propellant

2020 ◽  
Vol 984 ◽  
pp. 177-182
Author(s):  
Meng Lei Zhou ◽  
Li Na Zhang ◽  
Yang Liu ◽  
Feng Qiang Nan
Keyword(s):  
Impact Test ◽  
Three Dimensional ◽  
Single Layer ◽  
Video Observation ◽  
Coating Technology ◽  
Cladding Layer ◽  
Different Temperatures ◽  
Mechanical Performances ◽  
Cladding Layers ◽  
Layer Coating

In order to obtain better quality and mechanical performances, the coating process of super-porous propellants was optimized. The mechanical performances of super-porous propellants were tested, under some conditions with different temperatures, different numbers of cladding layers, different thicknesses of the cladding layer and different ratios of inner and outer layers, through many different analytical methods including impact test, interrupted-burning test and three-dimensional video observation test. The results show that the mechanical performances of super-porous propellants are positively correlated with the temperature, the coating thickness and the ratio of the outer layer. The double-layer coating also can obtain better coating effect than the single-layer coating.

High Temperature Properties of CoFe/CoNi and Fe/CoNi Biphase Microwires

2015 ◽  
Vol 233-234 ◽  
pp. 265-268 ◽  
Author(s):  
Irene Iglesias ◽  
Rhimou El Kammouni ◽  
Kseniay Chichay ◽  
Manuel Vazquez ◽  
Valeria Rodionova
Keyword(s):  
High Temperature ◽  
Room Temperature ◽  
Single Phase ◽  
Amorphous Structure ◽  
Magnetic Behaviour ◽  
Heating Process ◽  
Saturation Magnetostriction ◽  
Magnetostriction Constant ◽  
Different Temperatures ◽  
Drawing Technique

The objective of this work has been to analyze the high-temperature behavior of magnetically single-and biphase microwires because of its interest from fundamental and applications viewpoints. Two alloy compositions with amorphous structure covered by glass have been prepared as magnetically single phase microwires by quenching & drawing technique: CoFe-based with near zero saturation magnetostriction constant and Fe-based with positive saturation magnetostriction constant. The same wires were used as the core for magnetically biphase microwires. Second CoNi phase was deposited by electroplating. Magnitudes as saturation magnetization and hysteresis parameters are determined in the temperature range from room temperature up to 1200 K. We proceed to a comparative analysis of their magnetic behaviour at different temperatures as well as after cooling down to room temperature. Information on the Curie temperature of different phases and on the influence of heating process on the magnetic properties is thus derived.

Sign in / Sign up

Export Citation Format

Share Document