Microstructure of Zr-25at. %Al Melt Spun Ribbons.

1994 ◽  
Vol 364 ◽  
Author(s):  
L. Lutterotti ◽  
S. K. Pradhan ◽  
S. Gialanella ◽  
A. R. Yavari
Keyword(s):  
Phase Diagram ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Major Phase ◽  
X Ray ◽  
Metastable Structures ◽  
Melt Spun ◽  
Crystallographic Structures ◽  
Melt Spun Ribbons

AbstractFollowing a previous study in which we presented some microstructural aspects of meltspun ribbons having a composition close to Zr-25 at.% Al, we discuss now the crystallography of the phases observed in similar samples. We performed X-Ray diffraction analyses of ribbons and refined the observed crystallographic structures. We could identify a number of stable and metastable structures, according to the actual composition of the ribbons. We also estimated the percentage of each one of these phases. We did the same for some ribbons annealed at 750°C for several times. In this way we could follow the kinetics leading from the initial as-spun condition to the final one, featuring the L12 ordered Zr3Al, as the major phase, and other intermetallic phases of the Zr-Al phase diagram.

New method for the production of bulk amorphous materials of Nd–Fe–B alloys

2005 ◽  
Vol 20 (3) ◽  
pp. 563-566 ◽  
Author(s):  
Tetsuji Saito ◽  
Hiroyuku Takeishi ◽  
Noboru Nakayama
Keyword(s):  
Electron Microscopy ◽  
Amorphous Materials ◽  
Room Temperature ◽  
Amorphous Structure ◽  
X Ray Diffraction ◽  
Bulk Materials ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

We report a new compression shearing method for the production of bulk amorphous materials. In this study, amorphous Nd–Fe–B melt-spun ribbons were successfully consolidated into bulk form at room temperature by the compression shearing method. X-ray diffraction and transmission electron microscopy studies revealed that the amorphous structure was well maintained in the bulk materials. The resultant bulk materials exhibited the same magnetic properties as the original amorphous Nd–Fe–B materials.

EFFECT OF NANOCRYSTALLIZATION ANNEALING ON MAGNETIC PROPERTIES AND MAGNETOIMPEDANCE OF CO-BASE RIBBONS

2012 ◽  
Vol 05 ◽  
pp. 841-846
Author(s):  
AMIR KEYVANARA ◽  
REZA GHOLAMIPOUR ◽  
SHAMSEDIN MIRDAMADI ◽  
FARZAD SHAHRI ◽  
HOSSEIN SEPEHRI AMIN
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Magnetic Properties ◽  
Structural Studies ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Nanocrystalline Phases

Melt spun ribbons of Co 64 Fe 4 Ni 2 B 19 Si 8 Cr 3 alloy have been prepared and the nanocrystallization process was carried out by the heat treatment of the as spun ribbons above the crystallization temperature. Structural studies of the samples have been performed by transmission electron microscopy and X-ray diffraction. Magnetic properties of the samples and magnetoimpedance measurements were investigated and it was revealed that magnetic properties and magnetoimpedance of the samples deteriorate by the formation of nanocrystalline phases.

scholarly journals Crystallization Process and Microstructural Evolution of Melt Spun Al-RE-Ni-(Cu) Ribbons

Metals ◽  
2020 ◽  
Vol 10 (4) ◽  
pp. 443
Author(s):  
Francisco G. Cuevas ◽  
Sergio Lozano-Perez ◽  
Rosa María Aranda ◽  
Raquel Astacio
Keyword(s):  
Crystallization Process ◽  
Primary Crystallization ◽  
Amorphous Structure ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
The Stability

The crystallization process, both at the initial and subsequent stages, of amorphous Al88-RE4-Ni8 alloys (RE = Y, Sm and Ce) has been studied. Additionally, the consequences of adding 1 at.% Cu replacing Ni or Al were studied. The stability of the amorphous structure in melt spun ribbons was thermally studied by differential scanning calorimetry, with Ce alloys being the most stable. The effect of Cu to reduce the nanocrystal size during primary crystallization was analyzed by transmission electron microscopy. This latter technique and x-ray diffraction showed the formation of intermetallic phases at higher temperatures. A clear difference was observed for the Ce alloy, with a simpler sequence involving the presence of Al3Ni and Al11Ce3. However, for the Y and Sm alloys, a more complex evolution involving metastable ternary phases before Al19RE5Ni3 appears, takes place. The shape of the intermetallics changes from equiaxial in the Ce alloys to elongate for Y and Sm, with longer particles for Sm and, in general, when Cu is added to the alloy.

scholarly journals Experimental Realization of Heavily p-doped Half-Heusler CoVSn Compound

Energies ◽  
2020 ◽  
Vol 13 (6) ◽  
pp. 1459
Author(s):  
Sadeq Hooshmand Zaferani ◽  
Alireza Darebaghi ◽  
Soon-Jik Hong ◽  
Daryoosh Vashaee ◽  
Reza Ghomashchi
Keyword(s):  
Phase Diagram ◽  
Intermetallic Phases ◽  
X Ray Diffraction ◽  
Experimental Realization ◽  
X Ray ◽  
Plasma Sintering ◽  
Phase Compound ◽  
Thermoelectric Transport Properties ◽  
Spark Plasma ◽  
Multi Phase

Hypothetical half-Heusler (HH) ternary alloy of CoVSn has already been computationally investigated for possible spintronics and thermoelectric applications. We report the experimental realization of this compound and the characterizations of its thermoelectric properties. The material was synthesized by a solid-state reaction of the stoichiometric amounts of the elements via powder metallurgy (30 h mechanical milling and annealing at 900 °C for 20 h) and spark plasma sintering (SPS). The temperature-dependent ternary thermodynamic phase diagram of Co-V-Sn was further calculated. The phase diagram and detailed analysis of the synthesized material revealed the formation of the non-stoichiometry HH CoVSn, mixed with the binary intermetallic phases of SnV3, Co2Sn, and Co3V. The combination of X-ray diffraction, energy-dispersive X-ray spectroscopy, and thermoelectric transport properties confirmed the formation of a multi-phase compound. The analysis revealed the predicted thermoelectric features (zT = 0.53) of the highly doped CoVSn to be compromised by the formation of intermetallic phases (zT ≈ 0.007) during synthesis. The additional phases changed the properties from p- to overall n-type thermoelectric characteristics.

Effect of Cooling Rate on the Transformation Temperatures of Ni50Ti36Hf14 Melt-Spun Ribbons

2018 ◽  
Vol 930 ◽  
pp. 345-348
Author(s):  
R.L. Soares ◽  
Walman Benicio Castro
Keyword(s):  
Differential Scanning Calorimetry ◽  
Martensitic Transformation ◽  
Cooling Rate ◽  
Melt Spinning ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Memory Characteristics

Solidification structures and shape memory characteristics of Ni50Ti36Hf14(at.%) alloy ribbons prepared by melt spinning were investigated by means of differential scanning calorimetry and X-ray diffraction. In these experiments particular attention has been paid to change the velocity of cooling wheel from 20 to 40 m/s. Then the cooling rates of ribbons were controlled. The effect of this cooling rate on solidification structures and martensitic transformation behaviors is discussed. When the ribbon is produced at a wheel velocity of 40 m/s in melt spinning, the degree of supercooling becomes high because of its thinner thickness.

Metastable ordered austenite in rapidly solidified Fe-Al-C alloys

1989 ◽  
Vol 47 ◽  
pp. 516-517
Author(s):  
J. A. Sarreal
Keyword(s):  
Rapid Solidification ◽  
Melt Spinning ◽  
X Ray Diffraction ◽  
Austenitic Phase ◽  
X Ray ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons ◽  
Equilibrium Phases ◽  
Rapidly Solidified

Conventionally cast Fe-Al-C alloys are extremely brittle containing combinations of ferrite, carbide and other phases. Rapid solidification has the potential of altering the microstructure to subsequently change the resulting mechanical properties. An apparent conflict exist concerning the effect of rapid solidification on the resulting microstructure of these alloys. Inoue and co-workers, using transmission electron microscopy (TEM) and electron diffraction analyses, reported the presence of several non-equilibrium phases including austenite (fcc - γ) and ordered austenite (Ll2-γ') structures on alloys containing 1.7 to 2.1 C and 6 to 12 Al in weight % (w/o) on melt spun ribbons 30 μm in thickness. Han and Choo, using x-ray diffraction analysis on 30-48 μm thick melt spun ribbons concluded that this ordered fee phase is rather an austenitic phase in which phase decomposition accompanied by sideband phenomenon had occured.Single roller melt spinning technique was used to make ribbons 35-70 μm thick and 0.5-5 mm wide. X-ray diffration analysis showed single phase austenite for samples 2-6 w/o AI and 2 w/o C. Samples with 8-10 w/o AI and 2 w/o C also showed several superlattice lines in addition to the fundamental fcc peaks.

scholarly journals Improvement of the Magnetic Properties of Nanocrystalline Nd12.3(FeZrNbCu)81.7B6.0Alloys with Dy Substitutions

2015 ◽  
Vol 2015 ◽  
pp. 1-7
Author(s):  
Weiwei Yang ◽  
Leichen Guo ◽  
Zhimeng Guo ◽  
Guangle Dong ◽  
Yanli Sui ◽  
...  
Keyword(s):  
Magnetic Properties ◽  
Exchange Coupling ◽  
Single Phase ◽  
X Ray Diffraction ◽  
Material Microstructure ◽  
X Ray ◽  
Maximum Value ◽  
Transmission Electron ◽  
Melt Spun ◽  
Melt Spun Ribbons

Nd12.3−xDyxFe81.7Zr0.8Nb0.8Cu0.4B6.0  (x=0–2.5)ribbons have been prepared by melt-spun at 30 m/s and subsequent annealing. The influence of addition of Dy on the crystallization behavior, magnetic properties, and microstructure were investigated. Differential scanning calorimeter (DSC) and X-ray diffraction (XRD) revealed a single-phase material. Microstructure studies using transmission electron microscopy (TEM) had shown a significant microstructure refinement with Dy addition. Wohlfarth’s analysis showed that the exchange coupling interactions increased first with Dy contentxincreasing, reached the maximum value atx=0.5, and then slightly decreased withxfurther increasing. Optimal magnetic properties withJr=1.09 T,Hci=1048 kA/m, andBHmax=169.5 kJ/m3are achieved by annealing the melt-spun ribbons withx=0.5at% at 700°C for 10 min.

Hydrogen desorption properties of melt-spun and hydrogenated Mg-based alloys using in situ synchrotron X-ray diffraction and TGA

2011 ◽  
Vol 509 ◽  
pp. S629-S632 ◽  
Author(s):  
Siarhei Kalinichenka ◽  
Lars Röntzsch ◽  
Carsten Baehtz ◽  
Thomas Weißgärber ◽  
Bernd Kieback
Keyword(s):  
Hydrogen Desorption ◽  
X Ray Diffraction ◽  
X Ray ◽  
Melt Spun

TEM and X-Ray Examinations of Intermetallic Phases and Carbides Precipitation in an Fe-Ni Superalloy during Prolonged Ageing

2013 ◽  
Vol 212 ◽  
pp. 15-20
Author(s):  
Kazimierz J. Ducki ◽  
Jacek Mendala ◽  
Lilianna Wojtynek
Keyword(s):  
Heat Treatment ◽  
Solution Heat Treatment ◽  
Intermetallic Phase ◽  
Intermetallic Phases ◽  
Precipitation Process ◽  
Secondary Phases ◽  
X Ray Diffraction ◽  
Solid Samples ◽  
Structural Investigations ◽  
X Ray

The influence of prolonged ageing on the precipitation process of the secondary phases in an Fe-Ni superalloy of A-286 type has been studied. The samples were subjected to a solution heat treatment at 980°C for 2 h and water quenched, and then aged at temperatures of 715, 750 and 780°C at holding times from 0.5 to 500 h. Structural investigations were conducted using TEM and X-ray diffraction methods. The X-ray phase analyses performed on the isolates were obtained by anodic dissolution of the solid samples. After solution heat treatment the alloy has the structure of twinned austenite with a small amount of undissolved precipitates, such as carbide TiC, carbonitride TiC0.3N0.7, nitride TiN0.3, carbosulfide Ti4C2S2, Laves phase Ni2Si, and boride MoB. The application of ageing causes precipitation processes of γ-Ni3(Al,Ti), G (Ni16Ti6Si7), η (Ni3Ti), β (NiTi) and σ (Cr0.46Mo0.40Si0.14) intermetallic phases, as well as the carbide M23C6. It was found that the main phase precipitating during alloy ageing was the γ intermetallic phase.

scholarly journals The Texture and Structure of the Melt-Spun Co2MnAl-Type Heusler Alloy

Materials ◽  
2021 ◽  
Vol 14 (3) ◽  
pp. 501
Author(s):  
Pavel Diko ◽  
Viktor Kavečanský ◽  
Tomáš Ryba ◽  
Lucia Frolová ◽  
Rastislav Varga ◽  
...  
Keyword(s):  
Heusler Alloy ◽  
Dendritic Growth ◽  
Single Phase ◽  
Cellular Growth ◽  
Inhomogeneous Distribution ◽  
X Ray Diffraction ◽  
X Ray ◽  
Melt Spun ◽  
Wheel Side ◽  
Electron Back Scattered Diffraction

The structure of the Co2MnAl-type Heusler alloy in the form of a melt-spun ribbon was studied by electron microscopy, electron back-scattered diffraction (EBSD), and X-ray diffraction. The melt-spun ribbon consists of a homogeneous single-phase disordered Heusler alloy at the wheel side of the ribbon and an inhomogeneous single-phase alloy, formed by cellular or dendritic growth, at the free surface of the ribbon. Cellular growth causes the formation of an inhomogeneous distribution of the elemental constituents, with a higher Co and Al concentration in the centre of the cells or dendritic arms and a higher concentration of Mn at the cell boundaries. The EBSD analysis shows that the columnar crystals grow in the <111> crystal direction and are declined by about 10° against the direction of the spinning.

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