scholarly journals The Influence of Scandium on the Composition and Structure of the Ti-Al Alloy Obtained by “Hydride Technology”

Nanomaterials ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 918
Author(s):  
Natalia Karakchieva ◽  
Olga Lepakova ◽  
Yuri Abzaev ◽  
Victor Sachkov ◽  
Irina Kurzina
Keyword(s):  
Rietveld Method ◽  
Al Alloy ◽  
Surface Strength ◽  
Average Width ◽  
Near Surface ◽  
X Ray ◽  
Lamellar Structures ◽  
Quantitative Content ◽  
Transmission Electron ◽  
Composition And Structure

In this study the influence of scandium on the structural and phase state of the Ti-Al alloy obtained by the method of “Hydride Technology” (HT). The Rietveld method has allowed for determining the content of basic phases of the 49at.%Ti-49at.%Al-2at.%Sc system. By means of the methods of transmission electron microscopy (TEM) and X-ray spectral microanalysis, it has been established that scandium additives into the Ti-Al system result in the change of the quantitative content of phases in local regions of the structure. The Ti2Al5 phase has been found, and Ti2Al has been absent. In the morphology of substructures Ti-Al and Ti-Al-Sc there are lamellar structures or lamellae; the peculiarities of the distribution, fraction and size of which are influenced by scandium additives. The average width of Al-rich lamellae has been 0.85 µm, which is four times greater than that for the Ti-Al system (0.21 µm). For Ti-rich lamellae of the sample of the Ti-Al-Sc alloy, the average width of the lamellae has been 0.54 µm, and for Ti-Al it has been 0.34 µm. Based on the obtained data, a scheme of the distribution of phases in the composition of the Ti-Al-Sc alloy in the lamellar structures has been proposed. It has been established that in the Ti-Al-Sc system there is growth of the near-surface strength relative to Ti-Al. In this way, the microhardness of the Ti-Al-Sc alloy has amounted to 1.7 GPa, that is of the Ti-Al alloy which is 1.2 GPa.

Effect of the Pulse Laser Radiation on the Stabilization of the ZrO2 and HFO2 High-Temperature Phases

2015 ◽  
Vol 245 ◽  
pp. 200-203 ◽  
Author(s):  
Maxim Alexandrovich Pugachevskii ◽  
Viktor Igorevich Panfilov
Keyword(s):  
High Temperature ◽  
Transmission Electron Microscopy Data ◽  
X Ray Diffraction ◽  
X Ray ◽  
Good Thermal Stability ◽  
Quantitative Content ◽  
Electron Microscopy Data ◽  
Cubic Phases ◽  
Transmission Electron ◽  
Microscopy Data

The conditions of formation of the ZrO2 and HfO2 high-temperature (tetragonal and cubic) phases in the ablated nanoparticles were investigated. X-ray diffraction and transmission electron microscopy data demonstrate that laser intensities above 109 W/m2 ensure the formation of the ZrO2 high-temperature phases, while intensities above 5·109 W/m2 do the formation of the HfO2 high-temperature phases. Quantitative content of the high-temperature phases in layers of the ablated nanoparticles increases with raising the intensity. The obtained nanoparticles exhibit good thermal stability.

Grain Size Dependent Magnetic Properties of Nanocrystalline Sm [BE]Co [BD][BJ]/Cu

2001 ◽  
Vol 703 ◽  
Author(s):  
L. Bessais ◽  
C. Djéga-Mariadassou ◽  
J. Zhang ◽  
V. Lalanne ◽  
A. Percheron-Guégan
Keyword(s):  
Grain Size ◽  
Magnetic Properties ◽  
Rietveld Method ◽  
X Ray Diffraction ◽  
X Ray ◽  
Size Dependent ◽  
Transmission Electron ◽  
Average Grain Size ◽  
Magnetic Metal ◽  
Chemical Distribution

ABSTRACTThe evolution of both micro structural and magnetic properties of the Sm[BE]Co[BD][BJ] Cu powder, is studied as a function of soft co-milling time. The average grain size in the range 20 - 50 nm was determined by transmission electron microscopy coupled with x-ray diffraction using the Rietveld method. The particle shape and chemical distribution were investigated by elemental mapping, using wavelength dispersive x-ray analysis with electron microprobe analysis. The coercivity evolution shows that an optimum value of 6 kOe is obtained after 5 h co-milling. The microstructure analysis indicates that both materials are well mixed in nanometer scale. This technique appears as a potential route to synthesize nanocrystalline Sm[BE]Co[BD][BJ] isolated by non-magnetic metal Cu.

The Effect of Collimation On Sputtered Alcusi and Almg Microstructures And Electromigration Failure Characteristics

1993 ◽  
Vol 309 ◽  
Author(s):  
Thomas J. Licata ◽  
Timothy D. Sullivan ◽  
Roy S. Bass ◽  
James G. Ryan ◽  
David B. Knorr
Keyword(s):  
Electron Microscope ◽  
Sputter Deposition ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Failure Characteristics ◽  
X Ray ◽  
Aspect Ratios ◽  
Transmission Electron ◽  
Lower Strain ◽  
Induced Changes

AbstractIncreasing circuit densities produce higher metal wiring aspect ratios, and more difficult feature fill for damascene processing. One method of extending the use of sputter deposition to challenging aspect ratios is to collimate the sputtered flux using a collimator plate, and to avoid randomizing the collimated flux by using low process pressures corresponding to long sputtered atom mean free paths. In this paper, we discuss our fabrication of damascene AI-0.5Cu-2Si and AI-2Mg wiring using both collimated and uncollimated sputtering, and our observations of collimation-induced changes in Al alloy electromigration and microstructure. Our experiments show that collimation has only a small effect on AlCuSi, but a large effect on AIMg. Specifically, the median time to electromigration failure for collimated AIMg was ∼10X the value for uncollimated AlMg and ∼6X the values for collimated and uncollimated AlCuSi. Transmission electron microscope and x-ray diffraction analyses of these films show that the collimation-induced improvement in AIMg t50 is associated with the formation of smaller, lower strain grains which are clustered in very well-oriented (111) domains. We propose that the advantageous AlMg microstructure results from enhanced texture produced by aspects of the collimated deposition active in the absence of incoherent precipitates.

Microstructure and Oxidation of a Cast Nickel Aluminide Alloy

2002 ◽  
Vol 753 ◽  
Author(s):  
D. Y. Lee ◽  
M. L. Santella ◽  
I. M. Anderson ◽  
G. M. Pharr
Keyword(s):  
Nickel Aluminide ◽  
Volume Fraction ◽  
Surface Region ◽  
Oxidation Products ◽  
Al Alloy ◽  
X Ray Diffraction ◽  
Multivariate Statistical ◽  
Near Surface ◽  
X Ray ◽  
Spectrum Imaging

ABSTRACTSpecimens of the cast Ni3Al alloy IC221M were annealed in air at 900°C to examine the effects of oxidation and thermal aging on the microstructure. The alloy is comprised of a dendritically solidified γ-γ′ matrix containing γ+Ni5Zr eutectic colonies in the interdendritic regions. Microstructures of aged specimens were examined by optical microscopy and energy dispersive X-ray (EDX) spectrum imaging in the scanning electron microscope (SEM). Two primary changes in the microstructures were observed: (1) there is considerable homogenization of the cast microstructures with aging, and (2) the volume fraction of the γ+Ni5Zr eutectic decreases. Oxidation products were identified using x-ray diffraction and EDX spectrum imaging with multivariate statistical analysis (MSA). During the initial stages of oxidation, the first surface oxide to form is mostly NiO with small amounts of Cr2O3, ZrO2, NiCr2O4, and θ-Al2O3. Initially, oxidation occurs primarily in the interdendritic regions due to microsegregation of alloying elements during casting. With further aging, a continuous film of α-Al2O3 forms immediately beneath the surface that eventually evolves into a double layer of α-Al2O3 and NiAl2O4. Although these oxides are constrained to the near surface region, others penetrate to greater depths facilitated by oxidation of the γ+Ni5Zr eutectic colonies. These oxides appear in the microstructure as long, thin spikes of ZrO2 surrounded by a thin sheath of Al2O3.

scholarly journals Facile Hydrothermal Synthesis of Two-Dimensional Porous ZnO Nanosheets for Highly Sensitive Ethanol Sensor

2019 ◽  
Vol 2019 ◽  
pp. 1-7 ◽  
Author(s):  
Lai Van Duy ◽  
Nguyen Hong Hanh ◽  
Dang Ngoc Son ◽  
Pham Tien Hung ◽  
Chu Manh Hung ◽  
...  
Keyword(s):  
Gas Sensor ◽  
Gas Sensing ◽  
Fast Response ◽  
Two Dimensional ◽  
Ethanol Sensor ◽  
X Ray ◽  
Transmission Electron ◽  
Porous Nanosheets ◽  
Composition And Structure ◽  
Zno Nanosheets

Two-dimensional porous ZnO nanosheets were synthesized by a facile hydrothermal method for ethanol gas-sensing application. The morphology, composition, and structure of the synthesized materials were characterized by scanning electron microscopy, energy-dispersive X-ray spectroscopy, powder X-ray diffraction, and high-resolution transmission electron microcopy. Results showed that the synthesized ZnO materials were porous nanosheets with a smooth surface and a thickness of 100 nm and a large pore size of approximately 80 nm. The as-prepared nanosheets, which had high purity, high crystallinity, and good dispersion, were used to fabricate a gas sensor for ethanol gas detection at different operating temperatures. The porous ZnO nanosheet gas sensor exhibited a high response value of 21 toward 500 ppm ethanol at a working temperature of 400°C with a reversible and fast response to ethanol gas (12 s/231 s), indicating its potential application. We also discussed the plausible sensing mechanism of the porous ZnO nanosheets on the basis of the adopted ethanol sensor.

scholarly journals Nanocrystal Formation Via Yttrium Ion Implantation into Sapphire

1995 ◽  
Vol 396 ◽  
Author(s):  
E. M. Hunt ◽  
J. M. Hampikian ◽  
D. B. Poker
Keyword(s):  
Ion Implantation ◽  
Face Centered Cubic ◽  
Near Surface ◽  
X Ray ◽  
Ion Channeling ◽  
Transmission Electron ◽  
Face Centered ◽  
Amorphous Surface ◽  
Yttrium Ion ◽  
Nanosized Crystals

AbstractIon implantation has been used to form nanocrystals in the near surface of single crystal A12O3. The ion fluence was 5 x 1016 Y+/cm2, and the implant energies investigated were 100, 150, and 170 keV. The morphology of the implanted region was investigated using transmission electron microscopy, x-ray energy dispersive spectroscopy, Rutherford backscattering spectroscopy and ion channeling. The implantation causes the formation of an amorphous surface layer which contains spherical nanosized crystals with a diameter of ∼13 nm. The nanocrystals are randomly oriented and exhibit a face-centered cubic structure with a lattice pmeter of ∼4.1 A ± .02 A. Preliminary chemical analysis shows that these nanocrystals are rich in aluminum and yttrium and poor in oxygen relative to the amorphous matrix.

Defect Pair Formation by Implantation-Induced Stresses in High-Dose Oxygen Implanted Silicon-on-Insulator Material

1993 ◽  
Vol 316 ◽  
Author(s):  
J.D. Lee ◽  
J.C. Park ◽  
D. Venables ◽  
S.J. Krause ◽  
P. Roitman
Keyword(s):  
Defect Density ◽  
Silicon On Insulator ◽  
Surface Strain ◽  
High Dose ◽  
X Ray Diffraction ◽  
Near Surface ◽  
X Ray ◽  
Density Reduction ◽  
Transmission Electron ◽  
Pair Density

ABSTRACTDefect microstructure and the near-surface strain of high-dose oxygen implanted silicon-on-insulator material (SIMOX) were investigated as a function of dose, implant temperature, and annealing temperature by transmission electron microscopy and high resolution x-ray diffraction. Dislocation half loops (DHLs) begin to form by stress assisted climb at a critical stress level due to implantation-induced damage. DHLs evolve into through-thickness defect (TTD) pairs by expansion during annealing. Both DHL and TTD-pair density increase with higher implant dose and lower implant temperature. Possible methods for defect density reduction are suggested based on the results of this study.

scholarly journals Facile and Rapid Synthesis of Ultrafine PtPd Bimetallic Nanoparticles and Their High Performance toward Methanol Electrooxidation

2014 ◽  
Vol 2014 ◽  
pp. 1-7 ◽  
Author(s):  
Tiantian Xia ◽  
Hanrui Shen ◽  
Gang Chang ◽  
Yuting Zhang ◽  
Honghui Shu ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Performance ◽  
Direct Methanol Fuel Cells ◽  
Bimetallic Nanoparticles ◽  
Methanol Electrooxidation ◽  
X Ray ◽  
Transmission Electron ◽  
Composition And Structure ◽  
Direct Methanol

Uniform and sub-10 nm size bimetallic PtPd nanoparticles (NPs) have been synthesized via a simple and facile method without using any surfactants at an ambient temperature. As a green and clean reductive agent, ascorbic acid (AA) was employed for the coreduction of K2PtCl4and K2PdCl4in aqueous solution. The morphology, composition, and structure of PtPd NPs had been characterized by transmission electron microscopy (TEM), field emission high resolution transmission electron microscopy (FE-HRTEM), energy dispersive spectroscopy (EDS), X-ray diffraction (XRD), and X-ray photoelectron spectroscope (XPS). Comparing with both the monometallic Pt and Pd, the as-prepared alloy nanoparticles show superior electrocatalytic activity and better tolerance against poisoning by intermediates generated during methanol electrooxidation, which makes them a promising electrocatalysts for direct methanol fuel cells (DMFCs). Meanwhile, the green and simple approach could be easily extended to the manufacture of bimetallic or trimetallic alloy nanomaterials.

Investigation on B, Cr Doped Ni3Al Alloy Prepared by Self-Propagation High-Temperature Synthesis and Hot Extrusion

2013 ◽  
Vol 747-748 ◽  
pp. 124-131 ◽  
Author(s):  
Li Yuan Sheng ◽  
Jian Ting Guo ◽  
Chao Yuan ◽  
F. Yang ◽  
G.S. Li ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Mechanical Properties ◽  
High Temperature ◽  
Hot Extrusion ◽  
The Self ◽  
Al Alloy ◽  
Temperature Synthesis ◽  
X Ray ◽  
High Temperature Synthesis ◽  
Transmission Electron

The Ni3Al and Ni3Al-B-Cr alloys were fabricated by the self-propagation high-temperature synthesis with hot extrusion method. Their microstructure and mechanical properties were studied by using combination of X-ray diffraction, optical microscopy, transmission electron microscopy and compression test. Analysis of X-ray spectra exhibited that the elemental powders had been transformed to the Ni3Al phase after the self-propagation high-temperature synthesis processing. Microstructure examination showed that the alloy without extrusion consisted of coarse and fine grains, but the subsequent hot extrusion procedure homogenized the grain size and densified the alloy obviously. Transmission electron microscopy observations on the Ni3Al alloy revealed that Ni3Al, γ-Ni and Al2O3 particles were the main phases. When the boron and chromium were added, besides the β-NiAl phase, α-Cr phase and some Cr7Ni3 particles with stacking faults inside were observed. In addition, a lot of substructure and high-density dislocation arrays were observed in the extruded part, which indicated that the subsequent extrusion had led to great deformation and partly recrystallizing in the alloy. Moreover, the subsequent extrusion procedure redistributed the Al2O3 particles and eliminated the γ-Ni. These changes were helpful to refine the microstructure and weaken the misorientation. The mechanical test showed that the self-propagation high-temperature synthesis with hot extrusion improved the mechanical properties of the Ni3Al alloy significantly. The addition of B and Cr in Ni3Al alloy increased the mechanical properties further, but the compressive strength of the alloy was still lower than that synthesized by combustion. Finally, the self-propagation high-temperature synthesis with hot extrusion was a good method to prepare Ni3Al alloy from powder.

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