scholarly journals New Cu-Free Ti-Based Composites with Residual Amorphous Matrix

Materials ◽  
2016 ◽  
Vol 9 (5) ◽  
pp. 331 ◽  
Author(s):  
Mircea Nicoara ◽  
Cosmin Locovei ◽  
Viorel Șerban ◽  
R. Parthiban ◽  
Mariana Calin ◽  
...  
Keyword(s):  
Amorphous Matrix ◽  
Residual Amorphous Matrix

scholarly journals The precipitation of nanocrystalline structure in the joule heated Fe72Al5Ga2P11C6B4 metallic glasses

2012 ◽  
Vol 48 (2) ◽  
pp. 319-324 ◽  
Author(s):  
N. Mitrovic ◽  
S. Kane ◽  
S. Roth ◽  
A. Kalezic-Glisovic ◽  
C. Mickel ◽  
...  
Keyword(s):  
Metallic Glasses ◽  
Amorphous Alloys ◽  
Amorphous Matrix ◽  
Annealing Treatment ◽  
Nanocrystalline Structure ◽  
Heating Power ◽  
Cast State ◽  
Current Annealing ◽  
Residual Amorphous Matrix ◽  
Crystalline Component

In this study, the evolution of the nanostructure on dc Joule heated Fe72Al5Ga2P11C6B4 metallic glass ribbons have been investigated. Heating power per square area (PS) was ranging between 0.8 to 7.1 W/cm2 in order to get various stages of relaxation or nanocrystallization. The crystallization starts after applying PS ? 4.35 W/cm2 and the sample consist of residual amorphous matrix, a magnetic crystalline component and also a non-magnetic crystalline component (relative abundance of Fe in the crystalline phase is about 35 %). XRD measurements show that crystalline samples after current annealing consist of Fe3B, FeC, FeP and Fe3P compounds. On TEM micrograph a broad distribution of shapes and sizes is noticed, the latter range from about 60 to 350 nm, increasing by applied heating power. The decrease of the electrical resistivity after each current annealing treatment is rather small in comparison with other Fe-based amorphous alloys (only about 1.5 % for the highest PS). Partial nanocrystallization leads to increase of coercive field (from HC ? 7 A/m in the amorphous as-cast state up to 45 A/m) attributed to precipitation of magnetically harder compounds (Fe3B and FeC).

Temperature dependence of the soft magnetic character of Fe73.5Cu1Nb3Si13.5B9 amorphous and nanocrystalline alloys

2003 ◽  
Vol 18 (5) ◽  
pp. 1035-1038 ◽  
Author(s):  
J. Gonzáz
Keyword(s):  
Amorphous Alloy ◽  
Current Density ◽  
Curie Point ◽  
Amorphous Matrix ◽  
Body Centered Cubic ◽  
Soft Magnetic ◽  
Current Densities ◽  
Two Phases ◽  
Residual Amorphous Matrix ◽  
Magnetic Hardness

Results on microstructure and coercivity of current-annealed Fe73.5Cu1Nb3Si13.5B9 amorphous alloy treated at different current densities (12–56 A/mm2) and duration (0.5–720 min) are presented. Saturation magnetization and coercivity dependencies with the current density of the nanocrystalline samples is explained by considering the presence of two phases: nanocrystals of Fe(Si) body-centered cubic (bcc) grains and the residual amorphous matrix. An increase in the magnetic hardness observed when the sample was heated by current densities, giving rise to an increase in the sample temperature above the Curie point of the residual amorphous matrix, could be ascribed to exchange and dipolar decoupling of the Fe(Si)-bcc grains.

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.

Influence of Oxygen Contamination on Magnetic Properties of Amorphous and Nanocrystallized FeCuSiNbB Thin Films

2009 ◽  
Vol 152-153 ◽  
pp. 3-6 ◽  
Author(s):  
Johan Moulin ◽  
Bhaskar Kaviraj ◽  
El Houcine Oubensaïd ◽  
Francisco Alves ◽  
Uday P. Deshpande ◽  
...  
Keyword(s):  
Thin Films ◽  
Magnetic Properties ◽  
Amorphous Matrix ◽  
Rf Sputtering ◽  
Adsorption Coefficient ◽  
Deposition Rates ◽  
Oxygen Contamination ◽  
Bulk Oxygen ◽  
Residual Amorphous Matrix ◽  
Magnetic Hardness

Thin films of amorphous FeCuSiNbB alloy have been deposited by RF sputtering with various deposition rates. The bulk oxygen content has been characterized using EDS and XPS. Its dependence on deposition rate shows that water vapour in the sputtering chamber is at the origin of the contamination. It allows also estimating the adsorption coefficient of the oxygen on the sample to be around 15 % at 350 K. The magnetic hardness and the resistivity increase with the contamination in oxygen. In devitrified films, this increase is also related to an enrichment of the residual amorphous matrix in oxygen.

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.

scholarly journals Crystallization behavior of Zr62Al8Ni13Cu17 Metallic Glass

2017 ◽  
Vol 62 (2) ◽  
pp. 1023-1026 ◽  
Author(s):  
Mi Sun Jo ◽  
Jin Kyu Lee
Keyword(s):  
Metallic Glass ◽  
Crystalline Phase ◽  
Crystallization Behavior ◽  
Amorphous Matrix ◽  
Primary Crystallization ◽  
Isothermal Transformation ◽  
Avrami Analysis ◽  
Diffusion Controlled ◽  
Residual Amorphous Matrix ◽  
Glass Alloy

AbstractThe crystallization behavior has been studied in Zr62Al8Ni13Cu17metallic glass alloy. The Zr62Al8Ni13Cu17metallic glass crystallized through two steps. The fcc Zr2Ni phase transformed from the amorphous matrix during first crystallization and then the Zr2Ni and residual amorphous matrix transformed into a mixture of tetragonal Zr2Cu and hexagonal Zr6Al2Ni phases. Johnson-Mehl-Avrami analysis of isothermal transformation data suggested that the formation of crystalline phase is primary crystallization by diffusion-controlled growth.

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