Microstructure and Phase Transformation Temperatures of Two-Phase FeAl (B2) + FeAl2 Alloys

2014 ◽  
Vol 1760 ◽  
Author(s):  
Xiaolin Li ◽  
Martin Palm ◽  
Anke Scherf ◽  
Daniel Janda ◽  
Martin Heilmaier ◽  
...  
Keyword(s):  
Composition Dependence ◽  
Composition Range ◽  
Lamellar Microstructure ◽  
Lamellar Spacing ◽  
Al Alloys ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Creep Ductility ◽  
Heat Treated ◽  
Two Phases

ABSTRACTFe-Al alloys with about 55 to 65 at.% Al undergo a eutectoid transformation at 1095 °C: Fe5Al8 (ε) ↔ FeAl + FeAl2. Hence, as-cast Fe-Al alloys in this composition range show a very fine-scaled lamellar microstructure (average lamellar spacing below 500 nm) consisting of the two phases FeAl and FeAl2. The microstructure looks similar to the α2 + γ lamellar microstructure of Ti-Al-based alloys, which is known for having well-balanced properties in terms of creep, ductility and strength. However, there is limited knowledge about the properties of Fe-Al-based alloys in this composition range. In this study, a series of as-cast as well as heat-treated Fe-Al alloys with compositions between 57 and 63 at.% Al were investigated. The microstructures and crystal structures were analysed by scanning electron microscopy (SEM) and X-ray diffraction (XRD), respectively. The composition dependence of all transition temperatures was obtained by differential thermal analysis (DTA).

Phase Transformation in Granular Alloys of Cu2S-Ni3S2-Na2S System

2014 ◽  
Vol 353 ◽  
pp. 263-268
Author(s):  
Evgeny N. Selivanov ◽  
L.Yu. Udoeva ◽  
N.I. Selmenskich
Keyword(s):  
Solid Solution ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Hydrometallurgical Processing ◽  
Degree Of Separation ◽  
Large Particles ◽  
Dendrite Solidification ◽  
Sulfide Melt ◽  
Two Phases ◽  
Granular Alloys

The effect of Na2S on the phase composition and microstructure of tempered Cu2S-Ni3S2 alloys was studied by X-ray diffraction, optical microscopy and electron probe microanalysis (EPMA). It was found that quick crystallization of the sulfide melt leads to separation into two phases - Ni3S2 and a solid solution of Cu2S with Na2Cu4S5, moreover, nickel is concentrated in large particles and copper – in small ones. In contrast to the fine dendrite solidification of granular Cu2S-Ni3S2 alloys, in the ternary system there is a well-defined two-phase microstructure with rounded borders of the interface. Friability and a low microhardness of Cu2S - Na2Cu4S5 solid solution provide an autodecomposition of the sulfides melt by quenching into water (granulation). The degree of separation of copper and nickel depends on the overheating temperature and a quantity of Na2S in melt. The results can be used to hydrometallurgical processing of copper-nickel convert matt.

Two-Phase Structure of Fluorinated Powdered Silica Resulting from Deep Processing of Rice Wastes

2018 ◽  
Vol 7 (1) ◽  
pp. 38-44 ◽  
Author(s):  
А. Рашковский ◽  
A. Rashkovskiy ◽  
Е. Политова ◽  
E. Politova ◽  
А. Меркушкин ◽  
...  
Keyword(s):  
Photoelectron Spectroscopy ◽  
Inductively Coupled Plasma ◽  
Physicochemical Analysis ◽  
Nano Particles ◽  
Deep Processing ◽  
X Ray Diffraction ◽  
Two Phase ◽  
X Ray ◽  
Inductively Coupled ◽  
Two Phases

In this investigation the structure of «green» silica maid with rice husk has been studied by methods of physicochemical analysis. By method of X-ray diffraction it has been found that the samples of «green» silica powders are completely amorphous, and the observed amorphous halo consists of two components. By method of scanning electron microscopy it has been revealed that nano-particles of «green» SiO2 can form agglomerates and microstructures with dimensions from 0,1 to 500 microns, containing numerous pores, which presence has been confirmed by sorption measurements. By method of mass spectrometry with inductively coupled plasma has been found the presence of aluminum, titanium and nickel mechanical impurities in the «green» SiO2 powders. By method of X-ray photoelectron spectroscopy significant amount of fluorine atoms in «green» silica (up to 5% (at.)) has been revealed, which could be introduced in SiO2 in the process of its preparation. In such a case, it was found that fluorine interacts with «green» silica by means of two mechanisms, leading to appearance of two phases within fluorinated powders of «green» SiO2.

Nanostructure of Fe-C Alloys Prepared by Arc Melting in Vacuum

2017 ◽  
Vol 45 ◽  
pp. 218-228
Author(s):  
V. Karoutsos ◽  
Odyseas Venetsanos ◽  
Dimitris Geralis ◽  
Panagiotis Poulopoulos ◽  
C. Politis
Keyword(s):  
Lamellar Spacing ◽  
Isothermal Transformation ◽  
X Ray Diffraction ◽  
X Ray ◽  
Arc Melting ◽  
Heat Treated ◽  
Mean Size ◽  
Carbon Mapping ◽  
The One ◽  
Treatment Procedures

Three different Fe-C alloys were prepared in vacuum using the arc melting method: hypereutectoid (1.4% C), eutectoid (0.76% C) and hypoeutectoid (0.4% C). Unlike commercial steels, which they always contain Mn and other impurities, our samples were prepared by using high quality powders (99.999 wt.%). The samples were heat-treated and then observed with optical and scanning electronic microscopy (Zeiss EVO MA10). Selected samples were tested by microidentation (microhardness test). After isothermal transformation at 350 °C fine bainite nanostructures were observed in the hypoeutectoid sample, the mean size of which was found to be 50 nm. With the eutectoid sample, following different heat treatment procedures different micro-and nanostructures were measured: pearlite lamellar spacing, spheroidized cementite particles, and martensite needles, whose mean size is 145 nm, 290 nm and 200 nm respectively. The nanostructure of hypereutectoid sample after isothermal transformation at 650 °C, reveals the eutectoid and proeutectoid cementite lamellas with a mean spacing of 390 nm. X-ray diffraction pattern of eutectoid sample indicated the existence of cementite (Fe3C) content which is also confirmed by carbon mapping of pearlite colonies performed with Energy Dispersive X-ray Spectroscopy. The Vickers hardness of the samples compares well to the one of corresponding commercial steels.

Effect of the Platinum Electroplated Layer Thickness on the Coatings’ Microstructure

2017 ◽  
Vol 36 (3) ◽  
pp. 291-297
Author(s):  
Maryana Zagula-Yavorska ◽  
Kamil Gancarczyk ◽  
Jan Sieniawski
Keyword(s):  
Heat Treatment ◽  
Diffusion Zone ◽  
Roughness Parameter ◽  
Inconel 625 ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Inconel 625 Superalloy ◽  
Two Phases ◽  
Electroplating Process

AbstractCMSX 4 and Inconel 625 superalloys were coated by platinum layers (3 and 7 μm thick) in the electroplating process. The heat treatment of platinum layers (at 1,050 ˚C for 2 h) was performed to increase platinum adherence to the superalloys substrate. The diffusion zone obtained on CMSX 4 superalloy (3 and 7 μm platinum thick before heat treatment) consisted of two phases: γ-Ni(Al, Cr) and (Al0.25Pt0.75)Ni3. The diffusion zone obtained on Inconel 625 superalloy (3 μm platinum thick before heat treatment) consisted of the α-Pt(Ni, Cr, Al) phase. Moreover, γ-Ni(Cr, Al) phase was identified. The X-ray diffraction (XRD) results revealed the presence of platinum in the diffusion zone of the heat-treated coating (7 μm platinum thick) on Inconel 625 superalloy. The surface roughness parameter Ra of heat-treated coatings increased with the increase of platinum layers thickness. This was due to the unequal mass flow of platinum and nickel.

Experimental investigation on thermodynamic properties and crystal structure of La 0.78Ba0.22MnO3 compounds

2020 ◽  
Vol 34 (11) ◽  
pp. 2050101
Author(s):  
R. F. Hashimov ◽  
F. A. Mikailzade ◽  
S. V. Trukhanov ◽  
A. V. Trukhanov ◽  
D. M. Mirzayeva
Keyword(s):  
Crystal Structure ◽  
Diffraction Method ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
Thermo Gravimetric ◽  
Two Phase ◽  
Cubic Symmetry ◽  
Space Group ◽  
Two Phases ◽  
Rhombohedral Symmetry

In this work, powder [Formula: see text] samples (purity of 99.99 % and density of [Formula: see text] were used. The crystal structure of [Formula: see text] compound was studied by X-ray diffraction method. It was determined that the crystal structure of this compound consists of two phases at room-temperature and under normal condition. These structure phases correspond to the cubic symmetry with Pm-3m space group and rhombohedral symmetry with the R-3c space group. Thermo Gravimetric (TG), Differential Scanning Calorimetry (DSC), Differential Thermo Gravimetric (DTG) and Differential Thermal Analysis (DTA) of [Formula: see text] compound were carried out in a high-temperature range of [Formula: see text]. It has been found that at high-temperatures, two-phase transition occurs in this compound. The value of thermodynamic parameters was found out for each phase transit.

Effect of film composition on the orientation of (Ba,Sr)TiO3 grains in (Ba,Sr)yTiO2+ythin films

1999 ◽  
Vol 14 (12) ◽  
pp. 4657-4666 ◽  
Author(s):  
Debra L. Kaiser ◽  
Mark D. Vaudin ◽  
Lawrence D. Rotter ◽  
John E. Bonevich ◽  
Igor Levin ◽  
...  
Keyword(s):  
Amorphous Phase ◽  
Composition Dependence ◽  
Compressive Strain ◽  
Chemical Vapor ◽  
Growth Conditions ◽  
X Ray Diffraction ◽  
Two Phase ◽  
Film Composition ◽  
X Ray ◽  
Transmission Electron

Thin films of composition (Ba,Sr)yTiO2+y with 0.43 ≤ y ≤; 1.64, were deposited by metalorganic chemical vapor deposition on (100) MgO substrates at various growth conditions. X-ray diffraction and transmission electron microscopy studies showed that the films were composed of epitaxial Ba1–xSrxTiO3 (x ≈0.06) grains and an amorphous phase. The orientation of the tetragonal Ba1–xSrxTiO3 grains (pure a axis, pure c axis, or a mix of the two) was found to be strongly dependent upon film composition. This composition dependence is explained for the majority of the Ti-rich films by an analysis of average strains in the two-phase films, assuming a compressive strain of ≈1% in the amorphous phase.

scholarly journals INTERACTION OF LANTHANE AND LUTETIUM AT TEMPERATURE 1500–1600°C

2020 ◽  
Vol 86 (3) ◽  
pp. 19-25
Author(s):  
Olga Chudinovych ◽  
Nataliya Zhdanyuk
Keyword(s):  
Systematic Study ◽  
Composition Range ◽  
Phase Relationship ◽  
X Ray Diffraction ◽  
X Ray ◽  
Heat Treated ◽  
Wide Range ◽  
Concentration Dependences ◽  
Perovskite Type ◽  
Perovskite Type Structure

Materials based on La2O3–Lu2O3 system are promising candidates for a wide range of applications, but the phase relationship has not been studied systematically previously. To address this challenge, the subsection of the phase diagram for 1500 and 1600 °C have been elucidated. The samples of different compositions have been prepared from nitrate acid solutions by evaporation, drying and heat treatment at 1100, 1500 and 1600 °C. The phase relations in the binary La2O3–Lu2O3 system at 1500 and 1600 °C were studied from the heat treated samples using X-ray diffraction analysis and scanning electron microscopy in the overall concentration range. The X–ray analysis of the samples was performed by powder method using DRON-3 at room temperature (CuKa radiation). It was established that in the binary La2O3–Lu2O3 system there exist fields of solid solutions based on hexagonal (A) modification of La2O3, cubic (C) modification of Lu2O3, and with perovskite–type structure of LaLuO3 (R) with rhombic distortions. The systematic study that covered whole composition range excluded formation of new phases. The systematic study that covered whole composition range excluded formation of new phases. The boundaries of mutual solubility and concentration dependences the lattice parameters for all phases have been determined. The solubility of Lu2O3 in the hexagonal А–lanthanum modification is ~ 9 mol. % at 1500 and 1600 °С. The solubility of La2O3 in the cubic C–Lu2O3 is ~ 4 mol. % at 1500 and 7 mol. % at 1600 °С.

Microstructure and Phase Composition of Sputter-Deposited Zirconia-Yttria Films

1983 ◽  
Vol 30 ◽  
Author(s):  
R.W. Knoll ◽  
E.R. Bradley
Keyword(s):  
Phase Composition ◽  
Single Phase ◽  
Composition Range ◽  
X Ray Diffraction ◽  
Stabilized Zirconia ◽  
Partially Stabilized Zirconia ◽  
Transmission Electron ◽  
Heat Treated ◽  
High Bias ◽  
Sputter Deposited

ABSTRACTThin ZrO2 -Y2 O3 coatings ranging in composition from 3 to 15 mole % Y2 O3 were produced by rf sputter deposition. This composition range spanned the region on the equilibrium ZrO2 -Y2O3 phase diagram corresponding to partially stabilized zirconia (a mixture of tetragonal ZrO2 and cubic solid solution). Microstructural characteristics and crystalline phase composition of as-deposited and heat treated films (1100°C and 1500°C) were determined by transmission electron microscopy (TEM) and by x-ray diffraction (XRD). Effects of substrate bias (0 ∼ 250 volts), which induced ion bombardment of the film during growth, were also studied. The as-deposited ZrO2-Y2O3 films were single phase over the composition range studied, and XRD data indicated considerable local atomic disorder in the lattice. Films produced at low bias contained intergranular voids, pronounced columnar growth, and porosity between columns. At high bias, the microstructure was denser, and films contained high compressive stress. After heat treatment, all deposits remained single phase, therefore a microstructure and precipitate distribution characteristic of toughened, partially stabilized zirconia appears to be difficult to achieve in vapor deposited zirconia coatings.

scholarly journals Crystal structure of morimotoite from Ice River, Canada

2014 ◽  
Vol 29 (4) ◽  
pp. 325-330 ◽  
Author(s):  
Sytle M. Antao
Keyword(s):  
Crystal Structure ◽  
Rietveld Method ◽  
Phase 1 ◽  
Site Occupancy ◽  
X Ray Diffraction ◽  
Alkaline Complex ◽  
Two Phase ◽  
Homogeneous Sample ◽  
Weight Percentage ◽  
Two Phases

The crystal structure of a morimotoite garnet, ideally Ca3(Ti4+Fe2+)Si3O12, from the Ice River alkaline complex, British Columbia, Canada was refined by the Rietveld method, space group $Ia\overline 3 d$, and monochromatic synchrotron high-resolution powder X-ray diffraction (HRPXRD) data. Electron-microprobe analysis indicates a homogeneous sample with a formula {Ca2.91Mg0.05Mn2+0.03}Σ3[Ti1.09Fe3+0.46Fe2+0.37Mg0.08]Σ2(Si2.36Fe3+0.51Al0.14)Σ3O12. The HRPXRD data show a two-phase intergrowth. The reduced χ2 and overall R(F2) Rietveld refinement values are 1.572 and 0.0544, respectively. The weight percentage, unit-cell parameter (Å), distances (Å), and site occupancy factors (sofs) for phase-1 are as follows: 76.5(1)%, a = 12.156 98(1) Å, average <Ca–O> = 2.4383, Ti–O = 2.011(1), Si–O = 1.693(1) Å, Ca(sof) = 0.943(2), Ti(sof) = 0.966(2), and Si(sof) = 1.095(3). The corresponding values for phase-2 are 23.5(1)%, a = 12.160 67(2) Å, average <Ca–O> = 2.452, Ti–O = 1.988(3), Si–O = 1.704(3) Å, Ca(sof) = 1.063(7), Ti(sof) = 1.187(7), and Si(sof) = 1.220(8). The two phases cause strain that arises from structural mismatch and gives rise to low optical anisotropy. Because the two phases are structurally quite similar, a refinement using a single-phase model with anisotropic displacement parameters shows no unusual displacement ellipsoid for the O atom that requires a “split O-atom position”, as was done in previous studies.

Mechanical Properties of Ordered Fe-Al-X Alloys

1990 ◽  
Vol 213 ◽  
Author(s):  
Ujjwal Prakash ◽  
Robert A. Buckley ◽  
Howard Jones
Keyword(s):  
Electron Microscopy ◽  
Melt Spinning ◽  
Composition Range ◽  
Tensile Fracture ◽  
Strengthening Mechanisms ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Heat Treated ◽  
Rapidly Solidified

ABSTRACTFe-Al-X alloys (X = Cr, Mo) in the composition range 50 to 80 at. % Fe, 0 to 20 at. % X were rapidly solidified by chill-block melt-spinning. As-spun and heat treated ribbons were characterised by optical and electron microscopy and X-ray diffraction. Strengthening mechanisms were identified using microhardness measurements. Tensile fracture surfaces of ribbons reveal ductile to cleavage to intergranular fracture transitions with increasing Al-content. An increasing preponderance of cleavage fracture with increasing ternary substitution for Fe was observed.

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