Temat: 61.82.Bg - Prolib Integro

Skocz do pozycji: 1.

Tytuł:: Calculation of Lattice Relaxation in Some Substitutional Alloys Using a Green Function
Autorzy:: Das, S. K.
Datta Roy (Paul), S.
Tematy:: 61.72.Bb
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1995663.pdf Link otwiera się w nowym oknie
Opis:: In this paper we calculate nearest neighbour relaxation in some dilute substitutional alloys using a lattice static Green function and the Morse potential function. Distant neighbour relaxation is calculated by invoking a continuum approximation. The potential parameters for the unlike interactions are calculated using simple interpolation formulae. Using the above relaxation, we calculate volume changes in the above alloys. It is observed that the simple model predicts values which are in reasonably good agreement with the experimental values in all cases. The calculated values are also compared with those obtained from the Vegard law. For Au-Ag alloy, our model reproduces both the correct sign and the magnitude of the volume change, whereas the Vegard law cannot even give the sign of the volume change. This shows the inherent strength of the present model.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 2.

Tytuł:: Special Structures of Graphite Steels After High-Energy Electron Irradiation
Autorzy:: Alexandrova, N. M.
Tematy:: 61.80.Fe
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2011024.pdf Link otwiera się w nowym oknie
Opis:: The effect of high-energy electron irradiation on the structure and properties of the graphite steels have been investigated. It has been shown that single- and multicycle irradiation allows the improvement of hardness and ductility (≈ twice). A partial dissolution of the graphite, carbides redistribution, and refinement of the grain size allow the formation of the favorable surface structure after irradiation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 3.

Tytuł:: A Green Function Estimation of Correction to Vegards Law for isovalent Substitutional Defects in Alkali Halide Crystals
Autorzy:: Datta Roy (Paul), S.
Das, S. K.
Tematy:: 61.72.Bb
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2013286.pdf Link otwiera się w nowym oknie
Opis:: A Green function method is developed for estimation of lattice parameter r(χ) of an AX-BX solid solution over entire composition range (χ=0 to 1). The r(χ) obtained in the present method is different from the value r$\text{}_{V}$(χ) suggested by Vegard's law. We estimated the deviation from Vegard's law, r(χ)-r$\text{}_{V}$(χ), over entire composition range for isovalent substitutional defect in alkali halide crystals. When compared to X-ray diffraction measurements, we find that the deviation is in correct direction, variation of r(χ) with χ is consistent with experiment and the overall agreement is fairly good considering the accuracy of the experiment.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 4.

Tytuł:: Improving the Surface Properties of Cp-Ti by Pulsed Electro-Spark Deposition
Autorzy:: Yılmaz, M.
Atar, E.
Şahin, O.
Kayalı, E.
Tematy:: 68.47.De
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1293045.pdf Link otwiera się w nowym oknie
Opis:: Al-Ti intermetallic compounds were coated by electro-spark deposition. Commercially pure titanium (Cp-Ti) (grade 2) and aluminum rods were used as substrate and electrode materials, respectively. During the electro-spark deposition experiments the following pulse parameters in a group were used: pulse current amplitude, pulse duration and pause between the pulses of a pulse group with 100-300-500 A, 50-100 μs, and 100 μs, respectively. Al-Ti coatings having a thickness range of 15-30 μm were formed on the surface of titanium substrate using electro-spark deposition process. The coating properties such as the roughness and the thickness increased with increasing pulse duration and pulse current amplitude. The mass transfer coefficient decreased with increasing pulse current amplitude and pulse duration. The quality of the adhesion characters of the coatings, determined by Rockwell-C adhesion test, becomes worse from HF-2 to HF-4, due to increase of pulse current amplitude. Depending on the electro-spark deposition process parameters, the coating formed as AlTi or as layered structure consisting of AlTi+$AlTi_3$ when pulse current amplitude increases. The Al-Ti coatings include some micro cracks lying throughout the coating from surface to interface which is nature of this process. The maximum cross-sectional hardness of the coatings were in the range of 800-1150 HV.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 5.

Tytuł:: Slow Positron Beam Studies of the Stainless Steel Surface Exposed to Sandblasting
Autorzy:: Horodek, P.
Dryzek, J.
Kobets, A.
Kulik, M.
Lokhmatov, V.
Meshkov, I.
Orlov, O.
Pavlov, V.
Rudakov, A.
Sidorin, A.
Siemek, K.
Tematy:: 78.70.Bj
82.80.Yc
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1336525.pdf Link otwiera się w nowym oknie
Opis:: The paper presents slow positron beam studies of the stainless steel grade 304 AISI samples annealed in the flow $N_2$ atmosphere and sandblasted under different pressure from 1 to 7 bar. Heating of specimens caused formation of an additional layer on the surface which can be identified as oxides. Sandblasting reduces the thickness of the oxide layer and also defects concentration (vacancies as we suppose) decreases in dependence on pressure applied during blasting. Additionally, the atomic concentrations of oxygen have been obtained using nuclear methods (Rutherford backscattering and nuclear reactions) in the near surface layers of the studied samples.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 6.

Tytuł:: Defect Range and Evolution in Swift Xe-Ion Irradiated Pure Silver Studied by Positron Annihilation Technique
Autorzy:: Dryzek, J.
Horodek, P.
Skuratov, V.
Tematy:: 61.80.Jh
61.82.Bg
78.70.Bj; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1033261.pdf Link otwiera się w nowym oknie
Opis:: Variable energy positron beam and positron lifetime spectroscopy were used to study pure silver samples exposed to irradiation with swift Xe²⁶⁺ ions of energy 167 MeV with different dose: of 10¹³, 5×10¹³ and 10¹⁴ ions/cm². The positron lifetime spectroscopy revealed the presence of dislocations or vacancies associated with dislocations. They are distributed at the depth of about 6 μm, and this correlates with the ion implantation range, i.e. 9 μm. However, some defects are observed also to a depth of about 18 μm. At the depth less than 1 μm from the entrance surface strong dependence of positron diffusion length on the dose is observed. It indicates the presence of interstitial atoms and/or dislocation loops as a result of Xe²⁶⁺ ions implantation.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 7.

Tytuł:: Investigations of Au Segregation in AuNi Alloys by the Line Shape Analysis of Photoelectron Spectra
Autorzy:: Lesiak, B.
Biliński, A.
Jóźwik}, A.
Tematy:: 61.82.Bg
68.35.Dv
79.60.-i; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/2046828.pdf Link otwiera się w nowym oknie
Opis:: The surface segregation of Au in Au5Ni95 polycrystalline alloy is studied applying the line shape analysis, known as the fuzzy k-nearest neighbour rule, to the selected X-ray photoelectron and X-ray induced Auger spectra. Each line, characterised by the kinetic electron energy exhibited in the particular transition, samples the depth described by the mean escape depth depending on the inelastic mean free path of electron in the investigated material and the geometry of the measurement. The following electron transitions in the electron kinetic energy range 216.6-1486.6 eV are analysed: Au N$\text{}_{5}$N$\text{}_{67}$V, Ni 2p, Ni L$\text{}_{2}$M$\text{}_{23}$M$\text{}_{45}$-Ni L$\text{}_{3}$M$\text{}_{45}$M$\text{}_{45}$, Au 4d, Au 4f and the valence band transitions (overlapping Au 5d6s and Ni 3d4s transitions). The results of the quantitative analysis using the fuzzy k-nearest neighbour rule are compared to the results of quantitative analysis by the multiline approach which applies the Au 4f and Ni 2p photoelectron transitions. Both methods demonstrate Au surface segregation starting at the temperature above 200ºC. The line shape analysis was shown to be applicable for quantification of the surface region with possibility of investigating the in-depth non-uniform concentration profiles.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 8.

Tytuł:: Evaluation of Fracture Toughness of Thermal Sprayed and Hard Chrome Coated Aluminium-Zinc Alloy
Autorzy:: Altuncu, E.
İriç, S.
Tematy:: 46.50.+a
81.40.Np
61.82.Bg; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1031795.pdf Link otwiera się w nowym oknie
Opis:: The determination of fracture toughness of aluminium alloy aviation parts, exposed to cyclic mechanical loading, is an important engineering issue. The service life and crack resistance of such unprotected metallic parts is limited under corrosive operating conditions. The resistance against fracture cracking and corrosion resistance can be increased by the surface coatings. The scientific research of fracture toughness of coated metallic parts is being carried out in a comprehensive way. In this research, fracture toughness behaviour of high velocity oxy-fuel (HVOF) spray coated and conventional hard chrome plated aluminium-zinc alloy parts were compared and the results are discussed. The fracture surfaces are investigated and fracture toughness values are calculated. Electron microscopy analysis revealed significant differences in crack growth morphology and toughness values. As a result, the fracture toughness value is higher in hard chrome plated parts.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 9.

Tytuł:: Determination of the Young Modulus of Ti-TiAl₃ Metallic Intermetallic Laminate Composites by Nano-Indentation
Autorzy:: Yener, T.
Güler, S.
Siddique, S.
Walther, F.
Zeytin, S.
Tematy:: 72.80.Tm
61.82.Bg
68.55.Nq; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1398728.pdf Link otwiera się w nowym oknie
Opis:: Nano-indentation is an important technique to determine the Young modulus of multiphase materials where normal tensile tests are not appropriate. In this work, Ti-TiAl₃ metallic-intermetallic laminate composites have been fabricated successfully in open atmosphere using commercial purity Al and Ti foils with 250 μm and 500 μm initial thicknesses, respectively. Sintering process was performed at 700°C under 2 MPa pressure for 7.5 h. Mechanical properties including the Young modulus were determined after manufacturing. The Young moduli of metallic and intermetallic phases were determined as 89 GPa and 140 GPa, respectively. Microstructure analyses showed that aluminum foil was almost consumed by forming a titanium aluminide intermetallic compound. Titanium aluminides grow up through spherical shaped islands and metallic-intermetallic interface is a wavy form in Ti-Al system. Thus, the final microstructure consists of alternating layers of intermetallic compound and unreacted Ti metal. Microstructure and phase characterizations were performed by scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. Hardness of test samples was determined as 600 HV for intermetallic zone and 130 HV for metallic zone by the Vickers indentation method.
Dostawca treści:: Biblioteka Nauki

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Skocz do pozycji: 10.

Tytuł:: Study of Point Defect Distributions in Tantalum
Autorzy:: Djaafri, A.
Kadoun, A.
Driss-Khodja, M.
Elias, A.
Djaafri, T.
Tematy:: 61.82.Bg
61.80.Ed
61.72.jj
61.72.jn; Pokaż więcej
Wydawca:: Polska Akademia Nauk. Instytut Fizyki PAN
Powiązania:: https://bibliotekanauki.pl/articles/1029821.pdf Link otwiera się w nowym oknie
Opis:: We have investigated the point defect distributions in tantalum under irradiation by means of the Marlowe code based on the binary collision approximation. The study is carried out by simulating displacement cascades initiated with primary knock-on atom energies ranging from 5 to 20 keV. The Molière, Born-Mayer and average modified Lenz-Jensen potentials are used to describe the interactions between tantalum atoms. We have examined the creation of damage, the spatial defects distribution, and the vacancy clustering in tantalum. The results show that with an appropriate recombination radius, less than 16% of the created defects constitute permanent Frenkel pairs. Spatial configuration of defects indicates a separation between the two point defect types, vacancies and interstitials. The Molière potential favors the production of a greater number of displaced atoms and the development of voluminous cascades more than the other potentials. The cascade volume distributions deviate clearly from a Gaussian distribution. They are large and very stretched toward higher volumes for all used potentials. Only small vacancy clusters are formed in tantalum under irradiation and about 41% of the produced vacancies are considered as isolated
Dostawca treści:: Biblioteka Nauki

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