scholarly journals Effects of Co, Ni, and Cr addition on microstructure and magnetic properties of amorphous and nanocrystalline Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6) alloys

Nukleonika ◽  
2015 ◽  
Vol 60 (1) ◽  
pp. 103-108 ◽  
Author(s):  
Agnieszka Łukiewska ◽  
Jan Świerczek ◽  
Mariusz Hasiak ◽  
Jacek Olszewski ◽  
Józef Zbroszczyk ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Room Temperature ◽  
Amorphous Matrix ◽  
Paramagnetic State ◽  
Invar Effect ◽  
Average Hyperfine Field ◽  
Cr Addition ◽  
Partial Crystallization ◽  
Residual Amorphous Matrix ◽  
Microstructure And Magnetic Properties

Abstract Mössbauer spectra and thermomagnetic curves for the Fe86−xMxZr7Nb2Cu1B4 (M = Co, Ni, CoCr, and Cr, x = 0 or 6) alloys in the as-quenched state and after the accumulative annealing in the temperature range 600–800 K for 10 min are investigated. The parent Fe86Zr7Nb2Cu1B4 amorphous alloy is paramagnetic at room temperature, and substitution of 6 at.% of Fe by Co, Ni, and CoCr changes the magnetic structure – the alloys become ferromagnetic, whereas replacing 6 at.% of Fe with Cr preserves the paramagnetic state. After the heat treatment at 600 K, the decrease of the average hyperfine field induction, as compared to the as-quenched state, is observed due to the invar effect. After this annealing, the Curie temperature for all investigated alloys decreases. The accumulative annealing up to 800 K leads to the partial crystallization; α-Fe or α-FeCo grains with diameters in the range of 12–30 nm in the residual amorphous matrix appear.

EFFECT OF ANNEALING AT DIFFERENT TEMPERATURES ON THE STRUCTURE AND HARDNESS OF AL85Y8NI5CO2 ALLOY AMORPHOUS STRIPS

2018 ◽  
pp. 60-67
Author(s):  
A. G. Igrevskaya ◽  
A. I. Bazlov ◽  
N. Yu. Tabachkova ◽  
D. V. Louzguine ◽  
V. S. Zolotorevskiy
Keyword(s):  
Heat Treatment ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Maximum Value ◽  
Transmission Electron ◽  
Aluminum Solid Solution ◽  
Different Temperatures ◽  
Residual Amorphous Matrix

Aluminum-based metallic glasses are the new promising family of materials. However, the effect of heat treatment on the structure and properties of Al–Y–Ni–Co amorphous alloys has not been widely studied so far. In this paper, Al85Y8Ni5Co2 amorphous alloy strips were obtained by hardening on a rotary copper wheel. The effect of vacuum annealing at temperatures ranging from 100 to 500 °C for 30 minutes on the structure and hardness of these strips was investigated. Transmission electron microscopy, X-ray diffraction analysis, and differential scanning calorimetry were used to study changes in the structure of strips after heat treatment. Vickers microhardness was measured to investigate the effect of annealing on the mechanical properties of strips. The results obtained allowed for the conclusions made about changes in hardness depending on the Al85Y8Ni5Co2 alloy strip structure. It was found that as the temperature rises, strip microhardness increases reaching a maximum value of 575±7 HV after annealing at 350 °C, then it decreases with a further increase in the annealing temperature. It was shown that the Al85Y8Ni5Co2 alloy strips remain completely amorphous and no crystalline phases are detected in their structures after annealing at temperatures up to 250 °C for 30 minutes. A sharp increase in hardness after annealing at 350 °C is associated with 10–30 nm nanocrystals of an aluminum solid solution formed in the amorphous matrix and surrounded by a residual amorphous matrix, while further hardness decrease is associated with the increasing sizes of these crystals and Al3Y and Al19Ni5Y3 intermetallics formed in the structure.

Effect of Cr addition on room temperature hydrogenation of TiFe alloys

2021 ◽  
Author(s):  
Jee Yun Jung ◽  
Sang-In Lee ◽  
Mohammad Faisal ◽  
Hayoung Kim ◽  
Young-Su Lee ◽  
...  
Keyword(s):  
Room Temperature ◽  
Cr Addition

Magnetic Properties, Nanostructure, and Ordering Kinetics of Nb Additive FePtCu Films

2010 ◽  
Vol 638-642 ◽  
pp. 1743-1748
Author(s):  
G.J. Chen ◽  
Y.H. Shih ◽  
Jason S.C. Jang ◽  
S.R. Jian ◽  
P.H. Tsai ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Activation Energy ◽  
Magnetic Properties ◽  
Heating Rates ◽  
Fept Alloy ◽  
Ordering Kinetics ◽  
Nb Content ◽  
Kinetics Of ◽  
Nb Addition ◽  
Microstructure And Magnetic Properties

In this study,the (FePt)94-xCu6Nbx (x=0, 2.87, 4.52, 5.67) alloy films were prepared by co-sputtering. The effects of Nb addition content and heat treatment on the microstructure and magnetic properties of the polycrystalline FePtCu films are reported. Our previous experiments showed that the ordering temperature of the (FePt)94Cu6 films reduced to 320 °C, which is much lower than that of the FePt alloy. However, the grain growth after heat treatment limited the practical application in recording media. By adding the Nb content in the (FePt)94Cu6 film, the grain sizes of the films can be adjusted from 50 to 18nm, even for the films annealed at temperature as high as 600°C. DSC traces of as-deposited disorder films at different heating rates, to evaluate the crystallization of the order phase, revealed that the addition of Nb enhanced the activation energy of ordering from 87 kJ/mol to 288 kJ/mol for the (FePt)94-xCu6Nbx (x=0 and 2.87, respectively) films. The reduction of the grain size and the corresponding increase in the activation energy of the Fe-Pt-Cu-Nb films might result from the precipitation of the Nb atoms around the ordering FePt phase. The (FePt)94-xCu6Nbx (x=2.87) film showed a coercive force of 13.4 kOe and the magnetization of 687 emu/cc.

The Phase Analysis of Panzhihua Vanadic Titanomagnetite Ore before and after Heat Treatment

2013 ◽  
Vol 807-809 ◽  
pp. 2110-2114
Author(s):  
Shu Quan Wan ◽  
De Jun Lan ◽  
Hong Bo Han ◽  
Cai Long Zhou
Keyword(s):  
Heat Treatment ◽  
Phase Analysis ◽  
Room Temperature ◽  
Before And After

The phases of Panzhihua vanadic titanomagnetite ore were studied by using XRF and XRD. XRF results show that the original ore mainly contain the elements, Fe, Ti, Si, Ca, Al, S, Mg, P, Mn, V and etc. XRD results show that the main substances in original ore were Fe3O4 and FeTiO3, and the minor phases cannot be clearly studied by XRD. After heat treatment for 10h at 573K in atmospheric ambient, the phases of the ore have been slightly changed. And after heat treatment for 10h at 1073K in atmospheric ambient, then cooled for 48h to room temperature, the main phases of the ore have almost been changed to Fe2O3 and Fe2TiO5.

Local Structure and Er3+ Emission from Pseudo-Amorphous GaN:Er Thin Films

1998 ◽  
Vol 536 ◽  
Author(s):  
S. B. Aldabergenova ◽  
M. Albrecht ◽  
A. A. Andreev ◽  
C. Inglefield ◽  
J. Viner ◽  
...  
Keyword(s):  
Thin Films ◽  
Room Temperature ◽  
Amorphous Matrix ◽  
Broad Band ◽  
Resonant Absorption ◽  
Absorption Bands ◽  
Host Matrix ◽  
Transmission Electron ◽  
Infra Red ◽  
Band Edge Luminescence

AbstractWe report on strong Er3+ luminescence in the visible and infra-red regions at room temperature in amorphous GaN:Er thin films prepared by DC magnetron co-sputtering. The intensity of the Er3+ luminescence at 1.535 μm corresponding to 4I13/2 → 4I15/2 transitions is greatly enhanced after annealing at 750°C. In this material GaN crystallites have formed and embedded in the continuous amorphous matrix. The crystallites are 4 to 7 nm in diameter as analyzed by high resolution transmission electron microscopy. The absorption edge, extending three orders of magnitude in absorption coefficient in the spectral range from 0.5 to 3.5 eV, is superimposed on resonant absorption bands of Er3+ ions.The total photoluminescence spectrum consists of welldefined Er3+ luminescence peaks imposed on a broad band edge luminescence from the amorphous GaN host matrix.

Influence of Heat Treatment on Microstructure and Mechanical Properties of Selective Laser Melted TiAl6V4 Alloy

2018 ◽  
Vol 284 ◽  
pp. 615-620 ◽  
Author(s):  
R.M. Baitimerov ◽  
P.A. Lykov ◽  
L.V. Radionova
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Selective Laser Melting ◽  
Room Temperature ◽  
Base Alloy ◽  
Tensile Tests ◽  
Heat Treatments ◽  
Laser Melting ◽  
Microstructure And Mechanical Properties ◽  
Treatment Procedures

TiAl6V4 titanium base alloy is widely used in aerospace and medical industries. Specimens for tensile tests from TiAl6V4 with porosity less than 0.5% was fabricated by selective laser melting (SLM). Specimens were treated using two heat treatment procedures, third batch of specimens was tested in as-fabricated statement after machining. Tensile tests were carried out at room temperature. Microstructure and mechanical properties of SLM fabricated TiAl6V4 after different heat treatments were investigated.

Strength of Commercial Aluminum Alloys after Equal Channel Angular Pressing and Post-ECAP Processing

2006 ◽  
Vol 114 ◽  
pp. 91-96 ◽  
Author(s):  
Maxim Yu. Murashkin ◽  
M.V. Markushev ◽  
Julia Ivanisenko ◽  
Ruslan Valiev
Keyword(s):  
Mechanical Properties ◽  
Heat Treatment ◽  
Tensile Strength ◽  
Aluminum Alloys ◽  
Ultimate Tensile Strength ◽  
Equal Channel Angular Pressing ◽  
Room Temperature ◽  
Solution Treatment ◽  
Ecap Processing ◽  
Angular Pressing

The effects of equal channel angular pressing (ECAP), further heat treatment and rolling on the structure and room temperature mechanical properties of the commercial aluminum alloys 6061 (Al-0.9Mg-0.7Si) and 1560 (Al-6.5Mg-0.6Mn) were investigated. It has been shown that the strength of the alloys after ECAP is higher than that achieved after conventional processing. Prior ECAP solution treatment and post-ECAP ageing can additionally increase the strength of the 6061 alloy. Under optimal ageing conditions a yield strength (YS) of 434 MPa and am ultimate tensile strength (UTS) of 470 MPa were obtained for the alloy. Additional cold rolling leads to a YS and UTS of 475 and 500 MPa with 8% elongation. It was found that the post-ECAP isothermal rolling of the 1560 alloy resulted in the formation of a nano-fibred structure and a tensile strength (YS = 540 MPa and UTS = 635 MPa) that has never previously been observed in commercial non-heat treatable alloys.

scholarly journals Influence of Heat Treatment on the Microstructure and Magnetic Properties of Mn–Sn–Co–N Alloys

2013 ◽  
Vol 54 (10) ◽  
pp. 2007-2010 ◽  
Author(s):  
Keita Shinaji ◽  
Tsuyoshi Mase ◽  
Keita Isogai ◽  
Masashi Matsuura ◽  
Nobuki Tezuka ◽  
...  
Keyword(s):  
Heat Treatment ◽  
Magnetic Properties ◽  
Microstructure And Magnetic Properties

scholarly journals Facile and reproducible method of stabilizing $$\hbox {Bi}_2\hbox {O}_3$$ phases confined in nanocrystallites embedded in amorphous matrix

2021 ◽  
Vol 11 (1) ◽  
Author(s):  
Tomasz K. Pietrzak ◽  
Agata Jarocka ◽  
Cezariusz Jastrzębski ◽  
Tomasz Płociński ◽  
Marek Wasiucionek ◽  
...  
Keyword(s):  
Room Temperature ◽  
Amorphous Matrix ◽  
Glassy Matrix ◽  
Process Conditions ◽  
Oxide Ion Conductivity ◽  
Heat Treated ◽  
Reproducible Method ◽  
Glassy Materials ◽  
Quenching Method ◽  
Oxide Ion

AbstractBismuth sesquioxide ($$\hbox {Bi}_2\hbox {O}_3$$ Bi 2 O 3 ) draws much attention due to wide variety of phases in which it exists depending on the temperature. Among them, $$\delta$$ δ phase is specially interesting because of its high oxide ion conductivity and prospects of applications as an electrolyte in fuel cells. Unfortunately, it is stable only in a narrow temperature range ca. 730–830 $$^{\circ }$$ ∘ C. Our group has developed a facile and reproducible two-stage method of stabilizing $$\hbox {Bi}_2\hbox {O}_3$$ Bi 2 O 3 crystalline phases confined in nanocrystallites embedded in amorphous matrix. In the first stage, glassy materials were obtained by a routine melt-quenching method: pure $$\hbox {Bi}_2\hbox {O}_3$$ Bi 2 O 3 powders were melted in porcelain crucibles and fast-cooled down to room temperature. In the second step, the materials were appropriately heat-treated to induce formation of crystallites of $$\beta$$ β , $$\delta$$ δ or $$\gamma$$ γ $$\hbox {Bi}_2\hbox {O}_3$$ Bi 2 O 3 phases confined in a glassy matrix, depending on the process conditions. It was found out that the vitrification of the initial $$\hbox {Bi}_2\hbox {O}_3$$ Bi 2 O 3 and the subsequent nanocrystallization were unexpectedly possible due to the presence of some Al, and Si impurities from the crucibles. Systematic DTA, XRD, optical, Raman and SEM/EDS studies were carried out to investigate the influence of the syntheses processes and allowed us to determine conditions under which the particular phases appear and remain stable down to room temperature.

scholarly journals Effect of deposition current density and annealing temperature on the microstructure and magnetic properties of nanostructured Ni-Fe-W-Cu alloys

2019 ◽  
Vol 51 (2) ◽  
pp. 209-221 ◽  
Author(s):  
Milica Spasojevic ◽  
Dusan Markovic ◽  
Miroslav Spasojevic ◽  
Zoran Vukovic ◽  
Aleksa Maricic ◽  
...  
Keyword(s):  
Current Density ◽  
Amorphous Matrix ◽  
Ammonium Citrate ◽  
High Current ◽  
Cathodic Polarization Curve ◽  
Cu Alloy ◽  
Powder Particles ◽  
Current Densities ◽  
Deposition Current Density ◽  
Microstructure And Magnetic Properties

Ni-Fe-W-Cu alloy powders were obtained by electrodeposition from an ammonium citrate bath at current densities ranging between 70 and 600 mA cm-2. As the deposition current density increased, the contents of Fe and W in the alloy increased, and those of Ni and Cu decreased. The total cathodic polarization curve was recorded, and partial polarization curves for Ni, Fe and W deposition and hydrogen evolution were determined. The current efficiency of alloy deposition was measured. The powders contained an amorphous matrix and FCC nanocrystals of the solid solution of Fe, W and Cu in Ni. At high current densities, small-sized nanocrystals exhibiting high internal microstrain values were formed. Powder particles were dendrite- and cauliflower-shaped. The dendrites had a large number of secondary branches and higher-order branches containing interconnected globules. The density of branches was higher in particles formed at high current densities. The powders formed at high current densities exhibited higher magnetization. Annealing at temperatures up to 460?C resulted in structural relaxation, accompanied by an increase in magnetization. At temperatures above 460?C, amorphous matrix crystallization and FCC crystal growth took place, accompanied by a decrease in magnetization.

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