scholarly journals Structure and phase composition of hypereutectic silumin alloy Al – 20Si after compression plasma flows impact

2021 ◽  
pp. 25-33
Author(s):  
Vitali I. Shymanski ◽  
Antons Jevdokimovs ◽  
Nikolai N. Cherenda ◽  
Valiantsin M. Astashynski ◽  
Elizaveta A. Petrikova
Keyword(s):  
Phase Composition ◽  
Method Development ◽  
Diffraction Method ◽  
High Energy ◽  
High Rate ◽  
X Ray Diffraction ◽  
Plasma Flows ◽  
Silicon Phase ◽  
Compression Plasma Flows ◽  
Si Content

The results of structure and phase composition investigation in hypereutectic silumin alloy with 25 at. % Si content after high-energy pulsed compression plasma flows impact are presented in the work. The compression plasma flows impact with an absorbed energy density 25 – 40 J/cm2 allows to modify the sub-surface layer with a thickness up to 30 – 32 µm due to its melting and high rate solidification. By means of X-ray diffraction method, it was found the formation of two silicon phases with different grain sizes. The high-dispersed structure of silicon is presented in the Al-Si eutectic while the silicon phase with coarse grains exists in the primary crystals. The obtained results are the basis for a new method development for nanostructuring of the surface layers of hypereutectic silumin alloys increasing its wear resistance.

Phase composition depth profiles using spatially resolved energy dispersive X-ray diffraction

2004 ◽  
Vol 37 (6) ◽  
pp. 967-976 ◽  
Author(s):  
Andrew C. Jupe ◽  
Stuart R. Stock ◽  
Peter L. Lee ◽  
Nikhila N. Naik ◽  
Kimberly E. Kurtis ◽  
...  
Keyword(s):  
Phase Composition ◽  
Spatial Resolution ◽  
Zinc Coating ◽  
High Energy ◽  
Sulfate Attack ◽  
Energy Dispersive ◽  
X Ray Diffraction ◽  
X Ray ◽  
Spatially Resolved ◽  
Composition Profiles

Spatially resolved energy dispersive X-ray diffraction, using high-energy synchrotron radiation (∼35–80 keV), was used nondestructively to obtain phase composition profiles along the radii of cylindrical cement paste samples to characterize the progress of the chemical changes associated with sulfate attack on the cement. Phase distributions were acquired to depths of ∼4 mm below the specimen surface with sufficient spatial resolution to discern features less than 200 µm thick. The experimental and data analysis methods employed to obtain quantitative composition profiles are described. The spatial resolution that could be achieved is illustrated using data obtained from copper cylinders with a thin zinc coating. The measurements demonstrate that this approach is useful for nondestructively visualizing the sometimes complex transformations that take place during sulfate attack on cement-based materials. These transformations can be spatially related to microstructure as seen by computed microtomography.

Structure and Microwave Absorption Properties of Ho-Fe-Si Alloys

2018 ◽  
Vol 914 ◽  
pp. 117-123 ◽  
Author(s):  
Jia Liang Luo ◽  
Shun Kang Pan ◽  
Li Chun Cheng ◽  
Pei Hao Lin ◽  
Yu He ◽  
...  
Keyword(s):  
Ball Milling ◽  
Matching Condition ◽  
Peak Frequency ◽  
High Energy ◽  
X Ray Diffraction ◽  
Absorption Properties ◽  
Arc Melting ◽  
Microwave Absorbing Materials ◽  
Milling Method ◽  
Si Content

The Ho2Fe17-xSix (x=0.0, 0.1, 0.2, 0.3) alloys were prepared by arc melting and high energy ball milling method. The influence of the Si substitution on phase structure, morphology and electromagnetic parameters were investigated by X-ray diffraction (XRD), scanning electron microscopy (SEM) and vector network analyzer (VNA), respectively. The results show that the Ho-Fe-Si particles are flaky after the ball milling. The minimum absorption peak frequency shifts towards a lower frequency region with the increasing of Si content. The minimum RL of Ho2Fe16.7Si0.3 reaches-42.96 dB at 9.76 GHz, and the frequency bandwidth of R<-10 dB reaches about 2.64 GHz with the best matching condition d=1.6 mm. The reflection loss with the thickness ranging of 1.2-3.0 mm could reach-10 dB, which indicates the particles be considered as the promising microwave absorbing materials with a good absorption properties.

scholarly journals Synthesis of the Fe-6.5% wt. Si Alloy by Mechanical Alloying

2015 ◽  
Vol 13 ◽  
pp. 109-113 ◽  
Author(s):  
Cristina Daniela Stanciu ◽  
Florin Popa ◽  
Ionel Chicinaş ◽  
Olivier Isnard
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Nanocrystalline State ◽  
Compound Formation ◽  
Dsc Studies ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Si Content

Fe-Si alloy with a large Si content of 6.5 wt. % is obtained in nanocrystalline state by mechanical alloying of elemental iron and silicon powders. The mechanical alloying process was carried out using a high energy ball mill in argon atmosphere. Samples were collected after 0.5, 1, 2, 4, 6 and 8 hours of ball milling. The X-ray diffraction (XRD) studies indicate that after 4 hours of milling the Fe-Si alloy is formed. The powder magnetisation decreases upon increasing the milling time up to 4 hours as a consequence of the Fe-Si alloy formation. Upon heating, the DSC studies show the Fe3Si compound formation in the samples milled for milling times lower than 6 hours. Also, the Curie temperature of the alloy was evidenced.

Local Graded Structure in 6.5wt%Si-Fe Alloy and the Effect on Ductility

2005 ◽  
Vol 492-493 ◽  
pp. 59-62 ◽  
Author(s):  
Qiang Shen ◽  
Ran Li ◽  
Lian Meng Zhang
Keyword(s):  
Phase Composition ◽  
Powder Metallurgy ◽  
Deformation Behavior ◽  
Powder Metallurgy Method ◽  
Silicon Phase ◽  
Silicon Iron ◽  
Graded Structure ◽  
Composition And Structure ◽  
High Silicon ◽  
Si Content

The changes of phase composition and structure evolvement of Fe and Si powders with the ratio of 6.5wt%Si to 93.5wt%Fe were mainly studied. It is found that, the local graded structure, Fe-Fe(Si)-Fe3Si-(FeSi)-Si, forms due to the obvious diffusion and the alloying reaction between Fe and Si powders when sintering at 900-975oC. The graded structure, in which the high silicon phase based on Fe-Si alloys is packed by the low silicon solution based on Fe, exhibits a graded concentration of Si distribution. And most of the Fe-containing phase remains a state of lower Si content, less than that of 3wt%Si-Fe alloy, thus provides the good deformation behavior of rolling and cutting for the compacts. Therefore, it is feasible for the high silicon iron sheets to be produced by the powder metallurgy method.

scholarly journals A multireflection and multiwavelength residual stress determination method using energy dispersive diffraction

2018 ◽  
Vol 51 (3) ◽  
pp. 732-745 ◽  
Author(s):  
Marianna Marciszko ◽  
Andrzej Baczmański ◽  
Manuela Klaus ◽  
Christoph Genzel ◽  
Adrian Oponowicz ◽  
...  
Keyword(s):  
Residual Stress ◽  
Synchrotron Radiation ◽  
Diffraction Method ◽  
Surface Region ◽  
Grazing Incidence ◽  
High Energy ◽  
Energy Dispersive ◽  
X Rays ◽  
X Ray Diffraction ◽  
Near Surface

The main focus of the presented work was the investigation of structure and residual stress gradients in the near-surface region of materials studied by X-ray diffraction. The multireflection method was used to measure depth-dependent stress variation in near-surface layers of a Ti sample (grade 2) subjected to different mechanical treatments. First, the multireflection grazing incidence diffraction method was applied on a classical diffractometer with Cu Kα radiation. The applicability of the method was then extended by using a white synchrotron beam during an energy dispersive (ED) diffraction experiment. An advantage of this method was the possibility of using not only more than one reflection but also different wavelengths of radiation. This approach was successfully applied to analysis of data obtained in the ED experiment. There was good agreement between the measurements performed using synchrotron radiation and those with Cu Kα radiation on the classical diffractometer. A great advantage of high-energy synchrotron radiation was the possibility to measure stresses as well as thea0parameter andc0/a0ratio for much larger depths in comparison with laboratory X-rays.

Phase Transformation in Al3Ni2 Alloy during Mechanical Alloying and Heating of Milling Products

2013 ◽  
Vol 203-204 ◽  
pp. 272-275
Author(s):  
Marek Krasnowski ◽  
Tadeusz Kulik
Keyword(s):  
Mechanical Alloying ◽  
Phase Transformations ◽  
Intermetallic Phase ◽  
Diffraction Method ◽  
High Energy ◽  
X Ray Diffraction ◽  
Scanning Calorimetry ◽  
High Energy Ball Mill ◽  
Elemental Powder Mixture ◽  
Energy Ball

An elemental powder mixture corresponding to the Al3Ni2 phase stoichiometry was subjected to mechanical alloying in a high-energy ball mill. Products of this process after various milling times were investigated by differential scanning calorimetry. The phase transformations occurring in the material throughout milling and during heating in a calorimeter were investigated by X-ray diffraction method. This study revealed that a metastable nanocrystalline NiAl intermetallic phase was formed during the mechanical alloying process. Heating of the synthesised powders in the calorimeter caused phase transformations, the product of which was an equilibrium Al3Ni2 intermetallic phase or a mixture of NiAl, Al3Ni2 and Al3Ni intermetallic phases, depending on the milling time and the temperature up to which the material was heated.

Synthesis of the Fe-10%Si Nanocrystalline Powder by Mechanical Alloying

2014 ◽  
Vol 216 ◽  
pp. 283-287 ◽  
Author(s):  
Cristina Daniela Stanciu ◽  
Traian Florin Marinca ◽  
Florin Popa ◽  
Ionel Chicinaş ◽  
Olivier Isnard
Keyword(s):  
Mechanical Alloying ◽  
High Energy ◽  
Milling Process ◽  
Nanocrystalline Powder ◽  
Alloy Formation ◽  
X Ray Diffraction ◽  
Nanocrystalline State ◽  
High Energy Ball Mill ◽  
Energy Ball ◽  
Si Content

Fe-Si alloy with a Si content of 10 wt. % was obtained in nanocrystalline state by mechanical alloying of elemental iron and silicon powders. The mechanical alloying process was carried out in a high energy ball mill (Fritsch, Pulverisette 4) in argon atmosphere. The X-ray diffraction (XRD) studies indicated that after 4 hours of milling the Fe-Si alloy is formed. The mean crystallites size decreases down to 7 nm after 8 hours of milling. The particles morphology investigated by scanning electron microscopy (SEM) showed an evolution during milling process from two different kinds of particles to a one kind of particles with irregular shape. The magnetisation of powders decreases upon increasing the milling time up to 4 hours as a consequence of the Fe-Si alloy formation.

Investigation of the Phase Composition of Lithium-Titanium Ferrites by Thermo-Magnetometric and X-Ray Analysis

2015 ◽  
Vol 1085 ◽  
pp. 233-236 ◽  
Author(s):  
Alexander L. Astafyev ◽  
Elena N. Lysenko ◽  
Anatoly P. Surzhikov
Keyword(s):  
Magnetic Field ◽  
Phase Composition ◽  
Magnetic Phase ◽  
Diffraction Method ◽  
Precise Estimate ◽  
X Ray Diffraction ◽  
Thermo Gravimetric ◽  
X Ray ◽  
Gravimetric Measurements ◽  
Lithium Titanium

In the present work, the formation of the phase composition in the synthesis of lithium-titanium ferrite composition Li0.6Fe2.2Ti0.2O4 was investigated using thermo-magnetometry method based on thermo-gravimetric measurements in a magnetic field. Results of thermo-magnetometric analysis are compared with X-ray diffraction method data. It is shown that the thermo-magnetometry method better reflects the formation of the magnetic phase in the synthesis of ferrite, and therefore provides a more precise estimate the phase composition of the synthesis products.

scholarly journals Formation and Investigation of Plasma Powder Coatings Made of Oxide Ceramics Modified with High-Energy Effects

2018 ◽  
Vol 17 (5) ◽  
pp. 378-389 ◽  
Author(s):  
V. A. Okovity ◽  
F. I. Panteleenko ◽  
V. V. Okovity ◽  
V. M. Astashinsky ◽  
V. V. Uglov ◽  
...  
Keyword(s):  
Surface Layer ◽  
Zirconium Dioxide ◽  
Composite Coatings ◽  
High Energy ◽  
Morphological Properties ◽  
Multilayer Composite ◽  
Plasma Flows ◽  
Near Surface ◽  
Compression Plasma Flows ◽  
X Ray

The paper presents results of studying structure and properties of multilayer composite coatings optimized for their composition based on zirconium dioxide materials used for deposition of plasma coatings on the models of elements for anti-meteor shielding screens. The influence of plasma jet parameters (current, distance of sputtering, consumption of plasma-forming nitrogen gas) and fractional composition of an initial powder on characteristics of two-layer composite coatings based on nickel-chromium-aluminum-yttrium and zirconium dioxide on the elements of protective screens has been analyzed in the paper. Optimization has been carried out on the basis of obtaining maximum coefficient of powder utilization. The investigations have made it possible to ascertain specific features of elemental and phase composition, surface morphology, microstructure multilayer composite coatings on the basis of a solid layer of metal oxides and a viscous transition sub-layer subjected to compression plasma flows. The investigations have been executed with the help of scanning electron microscopy, energy dispersive x-ray spectral microanalysis, and x-ray diffraction analysis. It has been shown on the basis of the obtained results that the effect of compression plasma flows on multilayer composite coatings leads to a modification of a near-surface layer with a thickness up to 15 μm that presupposes its melting and subsequent high-speed crystallization which together provide an increase in its density, decrease in porosity while maintaining the initial phase state. Liquid-phase processes in the molten phase of the near-surface layer permit to modify morphological properties of the surface which are associated with its smoothing and lowering of roughness.

scholarly journals Mechanochemical synthesis of Co3C carbide with carbon nanotubes

2019 ◽  
Vol 20 (1) ◽  
pp. 13-17
Author(s):  
O. I. Nakonechna ◽  
M. M. Dashevski ◽  
A. M. Kurylyuk ◽  
N. M. Bilyavyna
Keyword(s):  
Crystal Structure ◽  
Carbon Nanotubes ◽  
Ball Mill ◽  
Diffraction Method ◽  
High Energy ◽  
X Ray Diffraction ◽  
Multiwalled Carbon ◽  
Reliability Factor ◽  
X Ray ◽  
Reaction Milling

Nanoscaled (about 15 nm of size) metastable carbide Co3C was synthesized in a high-energy planetary ball mill by mechanical alloying of a mixture of powder cobalt (75 at. %) and multiwalled carbon nanotubes (CNT, 25 at. %). Phase transformation takes place at reaction milling according to the reaction hcp-Co + CNT ® Co3C (reaction time is 120 - 220 min). The crystal structure of the Co3C carbide formed in the milling products was studied by X-ray diffraction method. It has revealed that the Co3C phase crystallizes in a Fe3C-type structure with a = 0.4982(3) nm, b = 0.6715(6) nm, c = 0.4457(7) nm, Pnma space group. The reliability factor RB is equal to 0.065 for 48 reflections presented at diffraction pattern. It is found that the crystal structure of the Co3C carbide obtained by reaction milling of the Co-CNT charge is significantly internally deformed (distortion degree of the CCo6 octahedron is 3.67 %) and contains the reduced interatomic Co-C distances (up to 0.188 nm). It was shown that the use of carbon nanotubes instead of graphite substantially reduces the duration of the Co3C carbide synthesis.

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