AEM analysis of solidification catalysts in atomized Fe-Ni

1986 ◽  
Vol 44 ◽  
pp. 584-585
Author(s):  
Matthew R. Libera
Keyword(s):  
Powder Particle ◽  
Alloy Composition ◽  
Particle Diameter ◽  
Metastable Phases ◽  
Liquid Droplets ◽  
Nucleation Kinetics ◽  
Ni Alloys ◽  
Nonequilibrium Solidification

The liquid droplets produced by atomization processes are believed to undergo substantial supercooling during solidification, because the catalytic heterogeneities, for statistical reasons, tend to be isolated in the larger droplets. This supercooling can lead to the nucleation of metastable phases. As part of a study on the effect of liquid supercooling on nonequilibrium solidification, three binary Fe-Ni alloys have been produced by conventional argon atomization (Fe-20Ni, Fe-30Ni, and Fe-40Ni). The primary variables in these experiments are: i) the alloy composition; and ii) the powder particle diameter (inversely proportional to supercooling). Of particular interest in this system is the competitive nucleation kinetics between the stable fee and metastable bec phases. Bcc is expected to nucleate preferentially with decreasing %Ni and decreasing particle diameter.

Quantitative Evaluation of The Chemical Composition of γ-γ’Interfaces in Ni Superalloys

2001 ◽  
Vol 7 (S2) ◽  
pp. 264-265
Author(s):  
H. A. Calderon ◽  
M. Benyoucef ◽  
N. Clement
Keyword(s):  
Mechanical Properties ◽  
Spatial Distribution ◽  
Chemical Composition ◽  
Large Volume ◽  
Alloy Composition ◽  
Volume Fraction ◽  
Alloying Elements ◽  
Local Distribution ◽  
Strain Fields ◽  
Ni Alloys

The excellent mechanical properties of Ni based superalloys depend upon the presence of γ’ particles (LI2 structure). Their volume fraction, spatial distribution and size determine the mechanical strength of these alloys. Ni alloys for technological applications make use of large volume fractions of precipitates where processes of coarsening and coalescence take place during service leading in some cases to deterioration of properties. Addition of different alloying elements prevents accelerated coalescence by retarding diffusion and thus improving the mechanical properties of such alloys. Coalescence can also take place under the influence of an applied stress leading to the formation of rafts of the y' phase. For example the microstructure changes during creep deformation, depending on the alloy composition, with the corresponding formation of dislocation networks and rafts of different morphologies [1]. The γ-γ’ interfaces are also different depending on the alloy composition and most likely to the local distribution of alloying elements and their strain fields.

An Automated Laboratory Apparatus for the Production of Rapidly Solidified Submicron Powders

1981 ◽  
Vol 8 ◽  
Author(s):  
Julius Perel ◽  
John F. Mahoney ◽  
Scott Taylor ◽  
Zef Shanfield ◽  
Carlos Levi
Keyword(s):  
Electron Microscope ◽  
Single Crystal ◽  
Liquid State ◽  
Metastable Phases ◽  
Liquid Droplets ◽  
Laboratory Apparatus ◽  
Material Scientist ◽  
Automated Instrument ◽  
Rapidly Solidified

ABSTRACTThe Electrohydrodynamic (EHD) method of spraying fine liquid droplets from a liquid state, in a vacuum environment, was developed and used to produce amorphous, microcrystalline, single crystal, bicrystalline and tricrystalline powders. Studies of these powders have contributed towards increasing the knowledge of extended solubility, nucleation, metastable phases, undercooling effects, etc. Coatings and films have been produced by collecting the liquid droplets before solidification. An automated instrument based upon the EHD method, the Micro-Particle Processor, is computer operated and allows a material scientist not completely acquainted with the EHD process to perform sophisticated experiments on materials of his choosing. Electron transparent powders close to 3μm and large powders up to l00μm have been collected and observed. Cooling rates above 107K/s have been achieved. Applications using powders include: new alloy compositions, use as AEM standards, in-situ remelt experiments in the electron microscope, etc.

Alignment of Primary Al3Ni Phases in Hypereutectic Al-Ni Alloys with Various Compositions under High Magnetic Field Gradients

2010 ◽  
Vol 649 ◽  
pp. 165-169 ◽  
Author(s):  
Tie Liu ◽  
Qiang Wang ◽  
Zhong Ying Wang ◽  
Dong Gang Li ◽  
Ji Cheng He
Keyword(s):  
Magnetic Field ◽  
Field Gradient ◽  
High Magnetic Field ◽  
Uniform Magnetic Field ◽  
Alloy Composition ◽  
Magnetic Field Gradient ◽  
Obvious Effect ◽  
Ni Alloys ◽  
Field Gradients ◽  
Magnetic Field Gradients

The microstructural changes of the primary Al3Ni phases in hypereutectic Al-Ni alloys solidified under various high magnetic field gradients were investigated. It was found that the application of a magnetic field gradient induced an aligned structure of the primary Al3Ni phases similar to those in a high uniform magnetic field. However, the high magnetic field gradient showed more obvious effect on the alignment of the primary Al3Ni phases than the uniform magnetic field, although this effect strongly depended on the alloy composition.

scholarly journals The Influence of Alloy Composition and microstructure on the corrosion behaviour of Cu-Ni alloys in seawater

1983 ◽  
Vol 34 (4) ◽  
pp. 167-178 ◽  
Author(s):  
L. J. P. Drolenga ◽  
F. P. Ijsseling ◽  
B. H. Kolster
Keyword(s):  
Alloy Composition ◽  
Corrosion Behaviour ◽  
Ni Alloys

scholarly journals Impact of Particle Size on Performance of Selective Laser Sintering Walnut Shell/Co-PES Powder

Materials ◽  
2021 ◽  
Vol 14 (2) ◽  
pp. 448
Author(s):  
Yueqiang Yu ◽  
Minzheng Jiang ◽  
Suling Wang ◽  
Yanling Guo ◽  
Ting Jiang ◽  
...  
Keyword(s):  
Surface Roughness ◽  
Particle Size ◽  
Powder Particle ◽  
Mechanical Test ◽  
Selective Laser Sintering ◽  
Particle Diameter ◽  
Laser Sintering ◽  
Walnut Shell ◽  
Powder Particle Size ◽  
Shell Powder

The agricultural and forestry waste walnut shell and copolyester hot-melt adhesives (Co-PES) powder were selected as feedstock. A kind of low-cost, low-power consumption, and environmentally friendly walnut shell/Co-PES powder composites (WSPC) was used for selective laser sintering (SLS). Though analyzing the size and morphology of walnut shell particle (≤550 μm) as well as performing an analysis of surface roughness, density, and mechanical test of WSPC parts with different particle sizes, results showed that the optimal mechanical performance (tensile strength of 2.011 MPa, bending strength of 3.5 MPa, impact strength of 0.718 KJ/m2) as walnut shell powder particle size was 80 to 120 μm. When walnut shell powder particle diameter was 120 to 180 μm, the minimum value of surface roughness of WSPC parts was 15.711 μm and density was approximately the maximum (0.926 g/cm3).

High temperature x-ray and calorimetric studies of phase transformations in quasicrystalline Ti–Zr–Ni alloys

1997 ◽  
Vol 12 (2) ◽  
pp. 434-438 ◽  
Author(s):  
R. M. Stroud ◽  
K. F. Kelton ◽  
S. T. Misture
Keyword(s):  
High Temperature ◽  
Alloy Composition ◽  
Stable Phase ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
X Ray ◽  
Ni Alloys ◽  
Partial Pressures ◽  
Calorimetric Studies

We present the first high temperature x-ray diffraction (HTXRD) studies of in situ quasicrystal-crystal and crystal-crystal transformations in Ti–Zr–Ni alloys. Together with differential scanning calorimetry studies, these x-ray measurements indicate three separate paths for the Ti–Zr–Ni quasicrystal-crystal transformation: single exothermic, single endothermic, or multiple endothermic. The mode of transformation depends on the alloy composition and the level of environmental oxygen. The crystalline products include the Ti2Ni, MgZn2 Laves, α−(Ti, Zr), and β−(Ti, Zr) phases. In the absence of oxygen, the endothermic transformation of the quasicrystal demonstrates that it is the lowest free energy (stable) phase at the Ti53Zr27Ni20 composition. Oxygen stabilizes the Ti2Ni phase, eliminating both the quasicrystal and the MgZn2 Laves phase, at partial pressures as low as a few hundred ppm.

scholarly journals Crystallography of Fe–Mn–Al–Ni Shape Memory Alloys

2021 ◽  
Author(s):  
A. Leineweber ◽  
A. Walnsch ◽  
P. Fischer ◽  
H. Schumann
Keyword(s):  
Experimental Data ◽  
Hough Transform ◽  
Alloy Composition ◽  
Electron Backscatter Diffraction ◽  
Phenomenological Theory ◽  
Cubic Symmetry ◽  
Ni Alloys ◽  
Electron Backscatter ◽  
Backscatter Diffraction ◽  
Habit Planes

AbstractThe microstructure of the martensite formed in Fe–Mn–Al–Ni alloys of varying composition, consisting of A2 austenite and A1-like martensite, was investigated by means of electron backscatter diffraction (EBSD). While sufficiently structured EBSD patterns clearly revealed a tetragonal distortion of the (twinned) martensite, robust indexing using Hough-transform-based methods were successful only by assuming a cubic symmetry of the martensite. It was shown that predictions made based on the Phenomenological Theory of Martensite Crystallography (PTMC) were well compatible with the experimental data, irrespective of the alloy composition. This includes a (near-)Pitsch orientation relationship and habit planes close to {110}A2.

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