Microstructure and Magnetic Properties of Two Phase β+γ Ferromagnetic Co-Ni-Al Alloys

2009 ◽  
Vol 154 ◽  
pp. 145-150 ◽  
Author(s):  
Wojciech Maziarz ◽  
Jan Dutkiewicz ◽  
Rafał Wróblewski ◽  
Marcin Leonowicz
Keyword(s):  
Electron Microscopy ◽  
Magnetic Properties ◽  
Magnetic Phase ◽  
Scanning Calorimetry ◽  
Two Phase ◽  
Ferromagnetic Alloys ◽  
Transmission Electron ◽  
Heat Treated ◽  
Phase Transition Temperatures ◽  
Microstructure And Magnetic Properties

The microstructure, texture and magnetic properties of two ferromagnetic alloys of composition Co35Ni37Al28 and Co37Ni35Al28 (in at. %) were investigated with optical microscopy (OM), analytical transmission electron microscopy (TEM), scanning electron microscopy (SEM) techniques as well as a vibrating sample magnetometer (VSM). The alloys were plastically deformed and heat treated in order to promote the martensitic transformation. Differential scanning calorimetry (DSC) revealed a drop of Ms temperature due to the increase of Co content in the alloys. The elongated twinned grains of size about 200 m and small precipitates of  phase were identified with the OM techniques. The TEM observations showed the twinned L10 non modulated martensite within the elongated grains and a small amount of ordered ’ phase after the heat treatment. The chemical composition of different martensite grains was established using point analyses of a HAADF-EDS technique. The magnetic phase transition temperatures were determined on the deformed samples using VSM method.

Crystal structure, microstructure, and magnetic properties of the Fe2CrSi nanostructured Heusler alloy elaborated by the mechanical alloying method

2020 ◽  
Vol 111 (8) ◽  
pp. 681-687
Author(s):  
Fatiha Djaidi ◽  
Hanane Mechri ◽  
Mohammed Azzaz
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Magnetic Properties ◽  
Mechanical Alloying ◽  
Heusler Alloy ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Disordered Crystal ◽  
Microstructure And Magnetic Properties

Abstract The Fe2CrSi nanostructured Heusler alloy was prepared by mechanical alloying followed by heat treatment. The structure, microstructure, and magnetic properties of the samples were studied by the following analysis methods: X-ray diffraction, scanning electron microscopy with energy dispersive X-ray spectrometry, transmission electron microscopy, and a vibrating sample magnetometer. The a-Fe (Si, Cr) solid solution with a disordered body centered cubic (bcc) crystal structure was obtained after 24 h of milling. An example of the sample milled for 32 h with a disordered crystal structure a-Fe(Si, Cr) was chosen to investigate the transformation with temperature using differential scanning calorimetry. The effect of annealing temperatures on the structural, microstructural, and magnetic properties of the ordered Fe2CrSi Heusler phase for the sample milled for 32 h was investigated.

scholarly journals Effect of Co Substitution on Crystallization and Magnetic Behavior of Fe85.45−xCoxCu0.55B14 Metallic Glass

Materials ◽  
2020 ◽  
Vol 13 (4) ◽  
pp. 919
Author(s):  
Lukasz Hawelek ◽  
Tymon Warski ◽  
Patryk Wlodarczyk ◽  
Marcin Polak ◽  
Przemyslaw Zackiewicz ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Magnetic Behavior ◽  
Magnetic Core ◽  
Scanning Calorimetry ◽  
Cu Content ◽  
Transmission Electron ◽  
Heat Treated ◽  
Core Losses ◽  
Diffraction Patterns ◽  
Nanocrystalline Phases

The effects of Co for Fe substitution on magnetic properties, thermal stability and crystal structure of Fe85.45−xCoxCu0.55B14 (x = 0, 2.5, 5, 7.5, 10) melt spun amorphous alloys were investigated. The Cu content was firstly optimized to minimize the energy of amorphous phase formation by the use of a thermodynamic approach. The formation of crystalline α-Fe type phase has been described using differential scanning calorimetry, X-ray diffractometry and transmission electron microscopy. The classical heat treatment process (with heating rate 10 °C/min) in vacuum for wound toroidal cores was optimized in the temperature range from 280 to 430 °C in order to obtain the best magnetic properties (magnetic saturation Bs and coercivity Hc obtained from the B(H) dependencies) at 50 Hz frequency. For optimal heat-treated samples, the complex magnetic permeability in the frequencies 104–108 Hz at room temperature was measured. Finally, magnetic core losses were obtained for 1 T/50 Hz and 1.5 T/50 Hz values for samples annealed at T = 310 °C. An analysis of transmission electron microscope images and electron diffraction patterns confirmed that high magnetic parameters are related to the coexistence of the amorphous and nanocrystalline phases.

Effect of Secondary Decomposition on Coercivity of Fe-Co-Cr Alloys with 15% Co

2015 ◽  
Vol 233-234 ◽  
pp. 623-628 ◽  
Author(s):  
Vladimir P. Menushenkov ◽  
Vladimir S. Shubakov
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Magnetic Properties ◽  
Coercive Force ◽  
Volume Fraction ◽  
Magnetic Measurements ◽  
Magnetic Treatment ◽  
Magnetic Insulation ◽  
Transmission Electron ◽  
Microstructure And Magnetic Properties

The microstructure and magnetic properties of Fe-Co-Cr alloys with 15 wt % Co were investigated using transmission electron microscopy and magnetic measurements. The secondary decomposition within both the α2-phase matrix and the α1-phase particles was observed for magnets subjected thermo-magnetic treatment and subsequent stepped aging or continuous-cooling treatments. During high-temperature treatments (630-600оC), when the α2phase is dominant (the volume fraction is more than 50%), the secondary decomposition of this phase takes place (α2→ α1'+ α2'). The deterioration of magnetic insulation of α1-phase particles results in the decrease in the coercive force of alloys. Below 600оC, when the α1phase is dominant (the volume fraction is more than 50%), the splitting of elongated α1-phase particles occurs. When the temperature of stepped-aging decreases in high steps, the secondary decomposition (α1→ α1'+ α2') leads to the splitting of initial α1-phase particles into fine slightly elongated particles and the decrease in the coercive force.

scholarly journals FEATURES OF STRUCTURE FORMATION AND CHANGES IN THE MECHANICAL PROPERTIES OF CAST Al-Mg-Si-Mn ALLOY WITH THE ADDITION OF (Ti+Zr)

2015 ◽  
Vol 55 (4) ◽  
pp. 282 ◽  
Author(s):  
Oleksandr Trudonoshyn ◽  
Maxim Puchnin ◽  
Kostiantyn Mykhalenkov
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
Scanning Electron Microscopy ◽  
Ageing Time ◽  
Tensile Tests ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Scanning Electron

<p>The as-cast and heat-treated structure of permanent mould castings of AlMg<sub>5</sub>Si<sub>2</sub>Mn alloys with different contents of Ti has been investigated by differential scanning calorimetry, hardness and microhardness measurements, tensile tests and fractography analyses, scanning electron microscopy, transmission electron microscopy, and energy dispersive X-ray analysis. We have established that α-Al dendrites can be nucleated on an Al-Ti substrate, and also that primary Mg<sub>2</sub>Si crystals can be nucleated on oxides, including oxides of Al and Ti compounds. The dependence of the change in mechanical properties on ageing time, and on the amount of Ti in the alloys, is shown.</p>

Effect of Cu Addition on Nanocrystallization Behavior in a Co-Based Soft Magnetic Metallic Glass

2008 ◽  
Vol 279 ◽  
pp. 125-132
Author(s):  
A.P. Srivastava ◽  
Dinesh Srivastava ◽  
K.G. Suresh ◽  
G.K. Dey
Keyword(s):  
Magnetic Properties ◽  
Melt Spinning ◽  
Magnetic Phase ◽  
Amorphous Ribbon ◽  
Dsc Analysis ◽  
Soft Magnetic ◽  
Heat Treated ◽  
Co Addition ◽  
Xrd And Tem ◽  
Microstructure And Magnetic Properties

Microstructure and magnetic properties of a nanocrystalline soft magnetic material having composition Co64.5 Fe3.5 Si16.5 B13 Ni1.5 Cu1 has been studied. Amorphous ribbon could be produced by melt spinning unit. DSC analysis showed four distinct crystallization events. Heat treated samples were characterized using XRD and TEM techniques. Co2B, and CoB phases were found to crystallize before magnetic phase a−Co. Addition of copper was proved to have adverse effect on soft magnetic properties.

Studies on the structural, thermal, and dielectric properties of fabricated Nylon 6,9/CaCu3Ti4O12 nanocomposites

2017 ◽  
Vol 24 (2) ◽  
pp. 185-194 ◽  
Author(s):  
Ramaswami Sachidanandan Ernest Ravindran ◽  
Paramanandam Thomas ◽  
Sahadevan Renganathan
Keyword(s):  
Electron Microscopy ◽  
Dielectric Properties ◽  
Dielectric Permittivity ◽  
Scanning Calorimetry ◽  
Melt Mixing ◽  
Two Phase ◽  
Oxalate Precursor ◽  
Transmission Electron ◽  
The Matrix ◽  
High Dielectric

AbstractNylon 6,9/CaCu3Ti4O12 (CCTO) nanocrystal composites with relatively high dielectric permittivity (220 at 100 Hz) were fabricated by melt mixing followed by hot pressing. The CCTO nanoceramics were synthesized using the oxalate precursor route, and the transmission electron microscopy studies exhibited that the crystallites are in the range of 20–200 nm. The nanocomposites were characterized using X-ray diffraction, scanning electron microscopy, thermogravimetric analysis, differential scanning calorimetry, and impedance analyzer to study their structural, thermal, and dielectric properties. The introduction of CCTO nanoparticles into the matrix had influenced the thermal properties. The effective dielectric permittivity of the nanocomposite increased by the augmentation of CCTO content in the Nylon 6,9. Our experimental outcomes showed that the fixed dielectric permittivity of such two-phase composite was established above 200 when the CCTO concentration was closer to its percolation threshold. The room temperature dielectric permittivity as high as 220 at 100 Hz has been achieved when the CCTO content increased to 58 vol% in the polymer and this was increased to 3845 at 150°C. The increase in AC conductivity with the increase in the CCTO content in the polymer matrix supported the hopping of the charge carrier conduction mechanism.

The effect of small additions of Cu on precipitation in Al-Mg-Si alloys

1990 ◽  
Vol 48 (2) ◽  
pp. 442-443
Author(s):  
M. Tamizifar ◽  
G. Cliff ◽  
R.W. Devenish ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Argon Atmosphere ◽  
Age Hardening ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Analytical Electron ◽  
Scanning Transmission

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.

scholarly journals Revisiting the Bøggild Intergrowth in Iridescent Labradorite Feldspars: Ordering, Kinetics, and Phase Equilibria

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 727
Author(s):  
Shiyun Jin ◽  
Huifang Xu ◽  
Seungyeol Lee
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Atom Probe ◽  
Phase Region ◽  
Two Phase ◽  
Subsolidus Phase ◽  
Plagioclase Feldspar ◽  
X Ray ◽  
Transmission Electron ◽  
Scanning Transmission

The enigmatic Bøggild intergrowth in iridescent labradorite crystals was revisited in light of recent work on the incommensurately modulated structures in the intermediated plagioclase. Five igneous samples and one metamorphic labradorite sample with various compositions and lamellar thicknesses were studied in this paper. The lamellar textures were characterized with conventional transmission electron microscopy (TEM) and scanning transmission electron microscopy (STEM). The compositions of individual lamellae were analyzed with high-resolution energy-dispersive X-ray spectroscopy (EDS) mapping and atom probe tomography (APT). The average structure states of the studied samples were also compared with single-crystal X-ray diffraction data (SC-XRD). The Na-rich lamellae have a composition of An44–48, and the Ca-rich lamellae range from An56 to An63. Significant differences between the lamellar compositions of different samples were observed. The compositions of the Bøggild intergrowth do not only depend on the bulk compositions, but also on the thermal history of the host rock. The implications on the subsolidus phase relationships of the plagioclase feldspar solid solution are discussed. The results cannot be explained by a regular symmetrical solvus such as the Bøggild gap, but they support an inclined two-phase region that closes at low temperature.

scholarly journals Study on Structure, Thermal Behavior, and Viscoelastic Properties of Nanodiamond-Reinforced Poly (vinyl alcohol) Nanocomposites

Polymers ◽  
2021 ◽  
Vol 13 (9) ◽  
pp. 1426
Author(s):  
Tomáš Remiš ◽  
Petr Bělský ◽  
Tomáš Kovářík ◽  
Jaroslav Kadlec ◽  
Mina Ghafouri Azar ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Analysis ◽  
Single Step ◽  
Poly Vinyl Alcohol ◽  
Scanning Calorimetry ◽  
X Ray Scattering ◽  
Transmission Electron ◽  
Primary Particles ◽  
Solution Casting Method ◽  
Average Size

In this work, advanced polymer nanocomposites comprising of polyvinyl alcohol (PVA) and nanodiamonds (NDs) were developed using a single-step solution-casting method. The properties of the prepared PVA/NDs nanocomposites were investigated using Raman spectroscopy, small- and wide-angle X-ray scattering (SAXS/WAXS), scanning electron microscopy (SEM), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). It was revealed that the tensile strength improved dramatically with increasing ND content in the PVA matrix, suggesting a strong interaction between the NDs and the PVA. SEM, TEM, and SAXS showed that NDs were present in the form of agglomerates with an average size of ~60 nm with primary particles of diameter ~5 nm. These results showed that NDs could act as a good nanofiller for PVA in terms of improving its stability and mechanical properties.

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