The effect of homogenization on microstructure and hardness of a large-scale high-aluminum Al4.4Co26Cr18Fe18Ni26Ti5.5 Compositionally Complex Alloy cast

2021 ◽  
Vol 0 (0) ◽  
Author(s):  
Florian Biermair ◽  
Gerald Ressel
Keyword(s):  
Large Scale ◽  
Lattice Parameter ◽  
Elemental Distribution ◽  
Cast State ◽  
Chemical Homogeneity ◽  
Cast Material ◽  
Complex Alloy ◽  
X Ray ◽  
High Entropy ◽  
Al Content

Abstract As any largescale cast material, specific Compositionally Complex Alloys or High Entropy Superalloys contain segregations, leading to unideal, inhomogeneous properties. This work presents the effects of a homogenization heat treatment at 1 150°C for 6 h of a large-scale cast Al4.4Co26Cr18Fe18Ni26Ti5.5 alloy. In order to reveal these effects, homogenized specimens were analyzed and compared to the as-cast state with regard to chemical homogeneity as well as the homogeneity of elemental solution by means of scanning electron microscopy, energy dispersive X-ray spectroscopy as well as X-ray diffraction and hardness measurements. Despite the increased Al content, intermetallic phases and segregations, observable in the as-cast state, dissolve during homogenization. Improved, but not full homogeneity of elemental distribution after annealing can be determined. The improved state of solution and homogeneity agrees with the increasing lattice parameter from 3.572 Å to 3.594 Å and the decreasing hardness from 320.3 HV10 to 245.2 HV10 during homogenization.

Microstructure and Mechanical Properties of Cr1-xAlxN Coating

2012 ◽  
Vol 531 ◽  
pp. 3-6
Author(s):  
C.L. Zhong ◽  
L.E. Luo
Keyword(s):  
Thin Films ◽  
Mechanical Properties ◽  
Magnetron Sputtering ◽  
Lattice Parameter ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Compound Coating ◽  
Cubic Structure

A series of Cr1-xAlxN coatings were deposited by reactive magnetron sputtering. The content, microstructure and the hardness of the thin films were characterized respectively with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and nanoindentor. The effect of Al content on the microstructure and hardness was studied. It was found that Cr1-xAlxN compound coating exhibits a cubic structure with (1 1 1) preferred orientations and that the lattice parameter of Cr1-xAlxN coatings decrease with the increase of Al content. The hardness of Cr1-xAlxN compound coating is higher than that of CrN and increases with the increase of Al content.

scholarly journals Laser-generated high entropy metallic glass nanoparticles as bifunctional electrocatalysts

Nano Research ◽  
2021 ◽  
Author(s):  
Jacob Johny ◽  
Yao Li ◽  
Marius Kamp ◽  
Oleg Prymak ◽  
Shun-Xing Liang ◽  
...  
Keyword(s):  
Metallic Glass ◽  
Energy Conversion ◽  
Photoelectron Spectroscopy ◽  
Surface Segregation ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
Elemental Distribution ◽  
X Ray ◽  
High Entropy ◽  
Depth Analysis

AbstractHigh entropy metallic glass nanoparticles (HEMG NPs) are very promising materials for energy conversion due to the wide tuning possibilities of electrochemical potentials offered by their multimetallic character combined with an amorphous structure. Up until now, the generation of these HEMG NPs involved tedious synthesis procedures where the generated particles were only available on highly specialized supports, which limited their widespread use. Hence, more flexible synthetic approaches to obtain colloidal HEMG NPs for applications in energy conversion and storage are highly desirable. We utilized pulsed laser ablation of bulk high entropy alloy targets in acetonitrile to generate colloidal carbon-coated CrCoFeNiMn and CrCoFeNiMnMo HEMG NPs. An in-depth analysis of the structure and elemental distribution of the obtained nanoparticles down to single-particle levels using advanced transmission electron microscopy (TEM), energy-dispersive X-ray spectroscopy (EDX), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) methods revealed amorphous quinary and senary alloy phases with slight manganese oxide/hydroxide surface segregation, which were stabilized within graphitic shells. Studies on the catalytic activity of the corresponding carbon-HEMG NPs during oxygen evolution and oxygen reduction reactions revealed an elevated activity upon the incorporation of moderate amounts of Mo into the amorphous alloy, probably due to the defect generation by atomic size mismatch. Furthermore, we demonstrate the superiority of these carbon-HEMG NPs over their crystalline analogies and highlight the suitability of these amorphous multi-elemental NPs in electrocatalytic energy conversion.

Tungsten nitride thin films prepared by MOCVD

1993 ◽  
Vol 8 (6) ◽  
pp. 1353-1360 ◽  
Author(s):  
Hsin-Tien Chiu ◽  
Shiow-Huey Chuang
Keyword(s):  
Thin Films ◽  
Mass Spectroscopy ◽  
Photoelectron Spectroscopy ◽  
Lattice Parameter ◽  
Binding Energies ◽  
Organic Chemical ◽  
Elemental Distribution ◽  
Tungsten Nitride ◽  
Wavelength Dispersive Spectroscopy ◽  
X Ray

Polycrystalline tungsten nitride thin films were grown by low pressure metallo-organic chemical vapor deposition (MOCVD) using (tBuN)2W(NHtBu)2 as the single-source precursor. Deposition of uniform thin films on glass and silicon substrates was carried out at temperatures 723–923 K in a cold-wall reactor, while the precursor was vaporized at 333–363 K. The growth rates were 2–10 nm/min depending on the condition employed. Bulk elemental composition of the thin films, studied by wavelength dispersive spectroscopy (WDS), is best described as WNx (x = 0.7–1.8). The N/W ratio decreased with increasing temperature of deposition. X-ray diffraction (XRD) studies showed that the films have cubic structures with the lattice parameter a = 0.414–0.418 nm. The lattice parameter decreased with decreasing N/W ratio. Stoichiometric WN thin films showed an average lattice parameter a of 0.4154 nm. X-ray photoelectron spectroscopy (XPS) showed that binding energies of the W4f7/2, W4f5/2, and N1s electrons were 33.0, 35.0, and 397.3 eV, respectively. Elemental distribution within the films, studied by secondary ion mass spectroscopy (SIMS) and Auger spectroscopy depth profilings, was uniform. The SIMS depth profiling also indicated that C and O concentrations were low in the film. Volatile products trapped at 77 K were analyzed by gas chromatography–mass spectroscopy (GC–MS) and nuclear magnetic resonance (NMR). Isobutylene, acetonitrile, hydrogen cyanide, and ammonia were detected in the condensable mixtures. Possible reaction pathways were proposed to speculate the origin of these molecules.

X-ray diffraction study of the effect of boron on lattice properties of Ni76Al24

1993 ◽  
Vol 8 (4) ◽  
pp. 741-744 ◽  
Author(s):  
Mohan P.V. Rao ◽  
Murthy K. Satyanarayana ◽  
S.V. Suryanarayana ◽  
Naidu S.V. Nagender
Keyword(s):  
Diffraction Study ◽  
Single Phase ◽  
Lattice Parameter ◽  
Small Addition ◽  
X Ray Diffraction ◽  
Fault Probability ◽  
Two Phase ◽  
X Ray ◽  
Al Content ◽  
Stacking Fault Probability

A small addition of boron is suggested to increase the ductility of the polycrystalline Ni3Al when the Al content is less than 25 at.%. Both metallographic and x-ray investigation have shown the alloys of Ni3Al (24 at.% Al) containing 0.20, 0.42, 0.79, 0.98, and 1.22 at.% B to be of single phase and that of 1.76 at.% B to be of two phase. With the addition of boron, the lattice parameter of the Ni3Al phase is found to increase. Microhardness measurements indicate that initially the hardness decreases for the alloy of 0.20 at.% B, while for the rest of the single phase alloys the hardness is found to increase with further addition of boron. The addition of boron increases the deformation stacking fault probability value except for the alloy with 0.20 at.% B.

Microstructure and Mechanical Properties of Ti1-xAlxN Thin Films

2012 ◽  
Vol 534 ◽  
pp. 93-96
Author(s):  
C.L. Zhong ◽  
P.A. Wei ◽  
L.E. Luo
Keyword(s):  
Thin Films ◽  
Lattice Parameter ◽  
Reactive Magnetron ◽  
X Ray Diffraction ◽  
X Ray ◽  
Al Content ◽  
Heat Treated ◽  
High Microhardness ◽  
Cubic Structure ◽  
Heat Treated Temperature

A series of Ti1-xAlxN thin films were deposited by reactive magnetron sputtering. The content, microstructure and the hardness of the thin films were characterized respectively with energy dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD) and nanoindentor. The effect of Al content on the microstructure and hardness was studied. It was found that Ti1-xAlxN compound thin films exhibits a cubic structure with (1 1 1) preferred orientations and that the lattice parameter of Ti1-xAlxN thin films decrease with the increase of Al content. The hardness of Ti1-x AlxN compound thin films is higher than that of TiN and increases with the increase of Al content. At the heat-treated temperature T = 600 °C, the Ti1-xAlxN thin films is still of high microhardness.

Elemental Distribution in CrNbTaTiW-C High Entropy Alloy Thin Films

2019 ◽  
Vol 25 (2) ◽  
pp. 489-500 ◽  
Author(s):  
Deodatta Shinde ◽  
Stefan Fritze ◽  
Mattias Thuvander ◽  
Paulius Malinovskis ◽  
Lars Riekehr ◽  
...  
Keyword(s):  
Thin Films ◽  
Formation Enthalpy ◽  
Amorphous Film ◽  
Atom Probe ◽  
Amorphous Structure ◽  
High Entropy Alloy ◽  
Elemental Distribution ◽  
X Ray ◽  
High Entropy ◽  
Strong Segregation

AbstractThe microstructure and distribution of the elements have been studied in thin films of a near-equimolar CrNbTaTiW high entropy alloy (HEA) and films with 8 at.% carbon added to the alloy. The films were deposited by magnetron sputtering at 300°C. X-ray diffraction shows that the near-equimolar metallic film crystallizes in a single-phase body centered cubic (bcc) structure with a strong (110) texture. However, more detailed analyses with transmission electron microscopy (TEM) and atom probe tomography (APT) show a strong segregation of Ti to the grain boundaries forming a very thin Ti–Cr rich interfacial layer. The effect can be explained by the large negative formation enthalpy of Ti–Cr compounds and shows that CrNbTaTiW is not a true HEA at lower temperatures. The addition of 8 at.% carbon leads to the formation of an amorphous structure, which can be explained by the limited solubility of carbon in bcc alloys. TEM energy-dispersive X-ray spectroscopy indicated that all metallic elements are randomly distributed in the film. The APT investigation, however, revealed that carbide-like clusters are present in the amorphous film.

Replacement of Vanadium by Ferrovanadium in Ti-Based BCC Alloys for Hydrogen Storage

2011 ◽  
Vol 170 ◽  
pp. 144-149 ◽  
Author(s):  
Manuel Tousignant ◽  
Jacques Huot
Keyword(s):  
Crystal Structure ◽  
Hydrogen Storage ◽  
Large Scale ◽  
Reversible Capacity ◽  
Cast State ◽  
X Ray ◽  
Practical Applications ◽  
Hydrogen Capacity ◽  
Arc Melting ◽  
Positive Effect

Ti-based BCC solid solutions are promising hydrogen storage applications. Unfortunately, the application of these alloys in large scale is hindered by the high cost of vanadium. The solution of this problem may be to replace vanadium by ferro-vanadium (FeV). Here, we report our recent investigation of compositions TiV1-xMn1+x and Ti(FeV)1-xMn1+x where x = -0.2, -0.1, 0, 0.1, 0.2. Each composition was synthesized by arc melting. No subsequent heat treatment was performed. The alloys’ crystal structure in as-cast state and after hydrogenation was inspected by X-ray powder diffraction. We found that replacement of vanadium by ferrovanadium had the positive effect of destabilization of the hydride which makes it more useful for practical applications. Also even if the total hydrogen capacity was reduced, the reversible capacity could be improved. We found that replacement of vanadium by ferrovanadium drastically change the crystal structure of hydrogenated compounds.

X-Ray absorption edge elemental imaging of B. thuringienis

1989 ◽  
Vol 47 ◽  
pp. 212-213
Author(s):  
R. L. Stears
Keyword(s):  
Absorption Edge ◽  
Elemental Distribution ◽  
X Rays ◽  
Differential Absorption ◽  
Synchrotron Source ◽  
High Brightness ◽  
X Ray ◽  
Elemental Imaging ◽  
Cellular Integrity ◽  
X Ray Absorption

Because of the nature of the bacterial endospore, little work has been done on analyzing their elemental distribution and composition in the intact, living, hydrated state. The majority of the qualitative analysis entailed intensive disruption and processing of the endospores, which effects their cellular integrity and composition.Absorption edge imaging permits elemental analysis of hydrated, unstained specimens at high resolution. By taking advantage of differential absorption of x-ray photons in regions of varying elemental composition, and using a high brightness, tuneable synchrotron source to obtain monochromatic x-rays, contact x-ray micrographs can be made of unfixed, intact endospores that reveal sites of elemental localization. This study presents new data demonstrating the application of x-ray absorption edge imaging to produce elemental information about nitrogen (N) and calcium (Ca) localization using Bacillus thuringiensis as the test specimen.

Preparation of cultured astrocytes for x-ray microanalysis

1989 ◽  
Vol 47 ◽  
pp. 988-989
Author(s):  
N.K.R. Smith ◽  
K.E. Hunter ◽  
P. Mobley ◽  
L.P. Felpel
Keyword(s):  
Cultured Cells ◽  
Elemental Content ◽  
Elemental Distribution ◽  
Sprague Dawley ◽  
X Ray ◽  
Cultured Astrocytes ◽  
Freeze Dried ◽  
Ultimate Objective

Electron probe energy dispersive x-ray microanalysis (XRMA) offers a powerful tool for the determination of intracellular elemental content of biological tissue. However, preparation of the tissue specimen , particularly excitable central nervous system (CNS) tissue , for XRMA is rather difficult, as dissection of a sample from the intact organism frequently results in artefacts in elemental distribution. To circumvent the problems inherent in the in vivo preparation, we turned to an in vitro preparation of astrocytes grown in tissue culture. However, preparations of in vitro samples offer a new and unique set of problems. Generally, cultured cells, growing in monolayer, must be harvested by either mechanical or enzymatic procedures, resulting in variable degrees of damage to the cells and compromised intracel1ular elemental distribution. The ultimate objective is to process and analyze unperturbed cells. With the objective of sparing others from some of the same efforts, we are reporting the considerable difficulties we have encountered in attempting to prepare astrocytes for XRMA.Tissue cultures of astrocytes from newborn C57 mice or Sprague Dawley rats were prepared and cultured by standard techniques, usually in T25 flasks, except as noted differently on Cytodex beads or on gelatin. After different preparative procedures, all samples were frozen on brass pins in liquid propane, stored in liquid nitrogen, cryosectioned (0.1 μm), freeze dried, and microanalyzed as previously reported.

X-ray mapping without STEM

1994 ◽  
Vol 52 ◽  
pp. 508-509
Author(s):  
Judith M. Brock ◽  
Max T. Otten
Keyword(s):  
Life Science ◽  
Materials Science ◽  
Chemical Elements ◽  
Full Description ◽  
Scanning System ◽  
Elemental Distribution ◽  
X Ray ◽  
Transmission Electron ◽  
Distribution Of Elements ◽  
Made In

A knowledge of the distribution of chemical elements in a specimen is often highly useful. In materials science specimens features such as grain boundaries and precipitates generally force a certain order on mental distribution, so that a single profile away from the boundary or precipitate gives a full description of all relevant data. No such simplicity can be assumed in life science specimens, where elements can occur various combinations and in different concentrations in tissue. In the latter case a two-dimensional elemental-distribution image is required to describe the material adequately. X-ray mapping provides such of the distribution of elements.The big disadvantage of x-ray mapping hitherto has been one requirement: the transmission electron microscope must have the scanning function. In cases where the STEM functionality – to record scanning images using a variety of STEM detectors – is not used, but only x-ray mapping is intended, a significant investment must still be made in the scanning system: electronics that drive the beam, detectors for generating the scanning images, and monitors for displaying and recording the images.

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