scholarly journals Process–Structure–Property Relationship in FeCoNiAlxMnx Complex Concentrated Alloys Processed by Additive Manufacturing

2021 ◽  
Author(s):  
A. Poulia ◽  
A. S. Azar ◽  
M. Schrade ◽  
J. S. Graff ◽  
C. Bazioti ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Structure Property ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
Type Curve ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Heat Treated ◽  
Scanning Transmission ◽  
Process Structure

AbstractFourteen alloys of the FeCoNiAlxMnx system were processed by laser metal deposition (LMD). The feedstock was a weighted and proportional blend of the containing elemental powders, targeting the nominal alloy compositions. Prior to processing, the composition and particle characteristics of the feedstock were assessed. The microstructural features and crystal structures of all LMD processed materials were characterized with scanning electron microscopy/energy dispersive spectroscopy and x-ray diffraction, in both as-received and heat-treated conditions. Selected samples were investigated via scanning transmission electron microscopy and electron backscattered diffraction for further structural understanding. Hardness tests, under various indentation loads and dwelling times, were performed to assess the mechanical properties of the processed samples. The results showed a rise in hardness as Al and Mn contents increase. The variation of hardness with composition follows a reverse sigma-type curve, reflecting the microstructural evolution and grain size variations in the alloys. Based on the hardness data, we suggest a trained and validated predictive model, which can be used in alloy design for future developments.

The effect of small additions of Cu on precipitation in Al-Mg-Si alloys

1990 ◽  
Vol 48 (2) ◽  
pp. 442-443
Author(s):  
M. Tamizifar ◽  
G. Cliff ◽  
R.W. Devenish ◽  
G.W. Lorimer
Keyword(s):  
Electron Microscopy ◽  
Analytical Electron Microscopy ◽  
Scanning Transmission Electron Microscope ◽  
Argon Atmosphere ◽  
Age Hardening ◽  
X Ray ◽  
Transmission Electron ◽  
Heat Treated ◽  
Analytical Electron ◽  
Scanning Transmission

Small additions of copper, <1 wt%, have a pronounced effect on the ageing response of Al-Mg-Si alloys. The object of the present investigation was to study the effect of additions of copper up to 0.5 wt% on the ageing response of a series of Al-Mg-Si alloys and to use high resolution analytical electron microscopy to determine the composition of the age hardening precipitates.The composition of the alloys investigated is given in Table 1. The alloys were heat treated in an argon atmosphere for 30m, water quenched and immediately aged either at 180°C for 15 h or given a duplex treatment of 180°C for 15 h followed by 350°C for 2 h2. The double-ageing treatment was similar to that carried out by Dumolt et al. Analyses of the precipitation were carried out with a HB 501 Scanning Transmission Electron Microscope. X-ray peak integrals were converted into weight fractions using the ratio technique of Cliff and Lorimer.

Understanding the Growth Mechanisms of Tin Oxide Nanowires by Chemical Vapor Deposition

2021 ◽  
Vol 21 (4) ◽  
pp. 2538-2544
Author(s):  
Nguyen Minh Hieu ◽  
Nguyen Hoang Hai ◽  
Mai Anh Tuan
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Chemical Vapor Deposition ◽  
Vapor Deposition ◽  
Chemical Vapor ◽  
Chemical Mapping ◽  
X Ray Diffraction ◽  
Lattice Constants ◽  
Transmission Electron ◽  
Scanning Transmission

Tin oxides nanowires were prepared by chemical vapor deposition using shadow mask. X-ray diffraction indicated that the products were tetragonal having crystalline structure with lattice constants a = 0.474 nm and c = 0.318 nm. The high-resolution transmission electron microscopy revealed that inter planar spacing is 0.25 nm. The results chemical mapping in scanning transmission electron microscopy so that the two elements of Oxygen and Tin are distributed very homogeneously in nanowires and exhibit no apparent elements separation. A bottom-up mechanism for SnO2 growth process has been proposed to explain the morphology of SnO2 nanowires.

Copper(I) Halide Nanoparticle-dispersed Glasses Prepared by Copper Staining

2005 ◽  
Vol 20 (9) ◽  
pp. 2480-2485 ◽  
Author(s):  
Kohei Kadono ◽  
Tatsuya Suetsugu ◽  
Takeshi Ohtani ◽  
Toshihiko Einishi ◽  
Takashi Tarumi ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Heat Treatment ◽  
Surface Region ◽  
Borosilicate Glasses ◽  
X Ray Diffraction ◽  
X Ray ◽  
Depth Profiles ◽  
Transmission Electron ◽  
Heat Treated ◽  
Glass Heat

Copper(I) chloride and bromide nanoparticle-dispersed glasses were prepared by means of a conventional copper staining. The staining was performed by the following process: copper stain was applied on the surfaces of Cl−- or Br−-ion-containing borosilicate glasses, and the glasses were heat-treated at 510 °C for various times. Typical exciton bands observed in the absorption spectra of the glasses after the heat treatment indicated that CuCl and CuBr particles were formed in the surface region of the glasses. The average sizes of the CuCl and CuBr particles in the glasses heat-treated for 48 h were estimated at 4.8 and 2.7 nm, respectively. The nanoparticles were also characterized by x-ray diffraction and transmission electron microscopy. Depth profiles of Cu and CuBr concentration in the glass heat-treated for 48 h were measured. Copper decreased in concentration monotonously with depth, reaching up to 60 μm, while the CuBr concentration had a maximum at about 25 μm in depth.

Microstructural analysis of high-pressure compressed C60

2001 ◽  
Vol 16 (7) ◽  
pp. 1960-1966 ◽  
Author(s):  
K. Miyazawa ◽  
H. Satsuki ◽  
M. Kuwabara ◽  
M. Akaishi
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
High Pressure ◽  
High Resolution ◽  
Microstructural Analysis ◽  
X Ray Diffraction ◽  
X Ray ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Lattice Planes

The structure and hardness of C60 bulk specimens compressed under 5.5 GPa at room temperature to 600 °C are investigated by high-resolution transmission electron microscopy, x-ray diffraction, and micro-Vickers hardness tests. A strong accumulation of the [1 1 0]tr orientation of high-pressure-treated C60 specimens was developed along the compression axis, and stacking faults and nano-sized deformation twins were introduced into the C60 specimens compressed at 450–600 °C. Curved lattice planes indicating a polymerization of C60 were observed by high resolution transmission electron microscopy (HRTEM). The polymerization of the high-pressure-compressed C60 is also supported by the computer simulation of HRTEM images.

TEM/STEM Characterization of Rapidly Solidified Aluminum Alloys

1985 ◽  
Vol 43 ◽  
pp. 30-31
Author(s):  
R. J. Kar ◽  
T. P. McHale ◽  
R. T. Kessler
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Aluminum Alloys ◽  
High Strength ◽  
Advanced Materials ◽  
Structure Property ◽  
Aerospace Applications ◽  
Transmission Electron ◽  
Scanning Transmission ◽  
Rapidly Solidified

Low-density and high strength-type rapidly solidified (RST) aluminum alloys offer promise for structural aerospace applications. At Northrop, as part of a continuing program to establish structure-property relationships in advanced materials, detailed transmission electron microscopy (TEM)/scanning transmission electron microscopy (STEM) of candidate RST aluminum-lithium (Al-Li) and high strength (7XXX-type) aluminum-copper-magnesium-zinc (Al-Cu-Mg-Zn) alloys is routinely performed. This paper describes typical microstructural features that we have observed in these alloys.Figure 1 illustrates the microstructure of an inert-gas atomized RST Al-Li-Cu-Mg-Zr alloy. Frequently the grain boundaries are decorated with continuous or semi-continuous stringers of oxide that are relatively opaque to the incident electron beam. These have been identified to be Al-,Mg-, and Li- containing oxides present on powder particle surfaces prior to consolidation, and which have not been adequately broken up and dispersed by post-consolidation processing. The microstructures of these alloys are generally characterized by unrecystallized grains and equiaxed sub-grains pinned by fine (0.2μm) precipitates. These have been identified to be Al3Zr dispersoids using a combination of selected area diffraction/energy-dispersive x-ray (SAD/EDX) methods.

Prepare of the New Structure PbTiO3 Nanowires and the Study of the Reversible Bending

2013 ◽  
Vol 331 ◽  
pp. 522-526
Author(s):  
Jiang Wang ◽  
Jian Li ◽  
You Wen Wang
Keyword(s):  
Crystal Structure ◽  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Stainless Steel ◽  
Hydrothermal Reaction ◽  
The Self ◽  
X Ray Diffraction ◽  
Electron Backscattered Diffraction ◽  
X Ray ◽  
Transmission Electron

When the self-made with Teflon lined with stainless steel reaction kettle is used to produce PbTiO3 nanowires with the adoption of hydrothermal reaction , PbTiO3 nanowires with new structure can be made when Pb/Ti equals 2.2. Observed through the Transmission Electron Microscopy (TEM), the bending feature of the PbTiO3 nanowires can be observed for several times when X-ray diffraction (XRD) and Electron Backscattered Diffraction (EBSD) are used to analyse and test the crystal structure of the nanowires. The result of the study shows that the degree of the bending of the PbTiO3 nanowires varies with the intensity of the electron beam from the Transmission Electron Microscopy, and its process can be reversible.

Effects of Thermo-Mechanical Treatment on the Microstructure of AA7085 Aluminum Alloy

2014 ◽  
Vol 794-796 ◽  
pp. 1193-1198 ◽  
Author(s):  
Hong Wei Tong ◽  
Wen Yi Liu ◽  
Guang Jie Huang ◽  
Qing Liu
Keyword(s):  
Electron Microscopy ◽  
Rolled Plate ◽  
X Ray Diffraction ◽  
Warm Deformation ◽  
X Ray ◽  
Free Zone ◽  
Transmission Electron ◽  
Hardness Tests ◽  
Continuous Chain

The microstructure of pre-aged AA7085 rolled plate was studied by means of hardness tests, optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and electrical conductivity tests. The results show that supper refined and homogeneous precipitates were formed during pre-aging, but the hardness of the alloy was still relatively low. There occurred a large number of dislocations when the warm deformation was introduced, and the size of the intragranular precipitates firstly increases and then decreases and then increases with the dislocation density increasing, which was caused by the role of dislocations on inhibiting the formation of GP zone and promoting the nucleation and transformation ofηphase. Meanwhile, the distribution of grain boundary precipitates also changed from continuous chain to coarsening interrupted distribution and the precipitate free zone (PFZ) broadened obviously.

scholarly journals New Insight on the Hydrogen Absorption Evolution of the Mg–Fe–H System under Equilibrium Conditions

Metals ◽  
2018 ◽  
Vol 8 (11) ◽  
pp. 967 ◽  
Author(s):  
Julián Puszkiel ◽  
M. Castro Riglos ◽  
José Ramallo-López ◽  
Martin Mizrahi ◽  
Thomas Gemming ◽  
...  
Keyword(s):  
Electron Microscopy ◽  
Transmission Electron Microscopy ◽  
Formation Mechanism ◽  
X Ray Diffraction ◽  
Equilibrium Conditions ◽  
Edge Structure ◽  
X Ray ◽  
Solid Diffusion ◽  
Transmission Electron ◽  
Scanning Transmission

Mg2FeH6 is regarded as potential hydrogen and thermochemical storage medium due to its high volumetric hydrogen (150 kg/m3) and energy (0.49 kWh/L) densities. In this work, the mechanism of formation of Mg2FeH6 under equilibrium conditions is thoroughly investigated applying volumetric measurements, X-ray diffraction (XRD), X-ray absorption near edge structure (XANES), and the combination of scanning transmission electron microscopy (STEM) with energy-dispersive X-ray spectroscopy (EDS) and high-resolution transmission electron microscopy (HR-TEM). Starting from a 2Mg:Fe stoichiometric powder ratio, thorough characterizations of samples taken at different states upon hydrogenation under equilibrium conditions confirm that the formation mechanism of Mg2FeH6 occurs from elemental Mg and Fe by columnar nucleation of the complex hydride at boundaries of the Fe seeds. The formation of MgH2 is enhanced by the presence of Fe. However, MgH2 does not take part as intermediate for the formation of Mg2FeH6 and acts as solid-solid diffusion barrier which hinders the complete formation of Mg2FeH6. This work provides novel insight about the formation mechanism of Mg2FeH6.

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