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1

Influence of Milling Time on Formation of NiTi Alloy Produced by High-Energy Ball Milling

Salwa P., Goryczka T.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 3

1017--1022

EN

Mixture of nickel and titanium powders were milled in planetary mill under argon atmosphere for 100 hours at room temperature. Every 10 hours the structure, morphology and chemical composition was studied by X-ray diffraction method (XRD), scanning electron microscope (SEM) as well as electron transmission microscope (TEM). Analysis revealed that elongation of milling time caused alloying of the elements. After 100 hours of milling the powders was in nanocrystalline and an amorphous state. Also extending of milling time affected the crystal size and microstrains of the alloying elements as well as the newly formed alloy. Crystallization of amorphous alloys proceeds above 600°C. In consequence, the alloy (at room temperature) consisted of mixture of the B2 parent phase and a small amount of the B19' martensite. Dependently on the milling time and followed crystallization the NiTi alloy can be received in a form of the powder with average crystallite size from 1,5 up to 4 nm.

2

Influence of Milling Time on Formation of NiTi Alloy Produced by High-Energy Ball Milling

Salwa P., Goryczka T.

Archives of Metallurgy and Materials

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2019

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Vol. 64, iss. 4

1301--1307

EN

Mixture of nickel and titanium powders were milled in planetary mill under argon atmosphere for 100 hours at room temperature. Every 10 hours the structure, morphology and chemical composition was studied by X-ray diffraction method (XRD), scanning electron microscope (SEM) as well as electron transmission microscope (TEM). Analysis revealed that elongation of milling time caused alloying of the elements. After 100 hours of milling the powders was in nanocrystalline and an amorphous state. Also extending of milling time affected the crystal size and microstrains of the alloying elements as well as the newly formed alloy. Crystallization of amorphous alloys proceeds above 600°C. In consequence, the alloy (at room temperature) consisted of mixture of the B2 parent phase and a small amount of the B19’ martensite. Dependently on the milling time and followed crystallization the NiTi alloy can be received in a form of the powder with average crystallite size from 1,5 up to 4 nm.

3

Influence of annealing on the microstructure of cast TiAl-based alloy

Lapin J., Pelachová T.

Journal of Achievements in Materials and Manufacturing Engineering

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2014

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Vol. 65, nr 2

53--60

EN

Purpose: The aim of the present work is to study the influence of annealing on the microstructure of cast TiAl-based alloy. Design/methodology/approach: Effect of annealing on the microstructure of cast Ti-46Al-8Ta (at.%) alloy was evaluated at temperatures ranging from 700 to 800°C. Fine grain convoluted microstructure of heat treated alloy consisted of small lamellar colonies of α2-Ti3Al (crystal structure D019) intermetallic phase within γ-TiAl (crystal structure L10) phase. Findings: Annealing leads to precipitation of α2 and τ(crystal structure B82) particles at the grain boundaries at the expense of the α2 laths. This process is connected with a depletion of the grain boundaries of Ti and Ta and formation of Al rich γ phase. Lattice parameter a of the γ phase decreases, c increases and aspect ratio c/a increases with increasing time and temperature of ageing. Research limitations/implications: The annealing leads to an increase of lattice parameters a and c and decrease of the aspect ratio c/a of both α2 and τ phases. Originality/value: This work present the effect of long-term annealing on microstructure stability and lattice parameters of coexisting phases in this alloy at temperatures ranging from 700 to 800ºC.

4

Investigation on Irreversible Expansion of 1,3,5-Triamino-2,4,6-trinitrobenzene Cylinder

Sun J., Kang B., Zhang H., Liu Y., Xia Y., Yao Y., Liu X.

Central European Journal of Energetic Materials

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2011

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Vol. 8, nr 1

69-79

EN

In this study, the irreversible expansion of TATB cylinder is investigated. No evident variation of the lattice parameters is observed on TATB crystal. The density of TATB powder decreases by only about 0.02% after it suffered from thermal cycling process at the range from -54 C to 74 C, while the density of TATB cylinder decreases by about 1.0%. It is suggested that the density variation of TATB powder has little contribution to the density decrease of TATB cylinder. Therefore, the increasing interstices between TATB powder originated from the thermal cycling should be responsible to the irreversible expansion of TATB cylinder.

5

Two-temperature microscale heat transfer model. Part 2, Determination of lattice parameters

Majchrzak E., Poteralska J.

Prace Naukowe Instytutu Matematyki i Informatyki Politechniki Częstochowskiej

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2010

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Vol. 9, nr 1

109-119

EN

Two-temperature microscale heat transfer model is presented. This model contains two energy equations determining the heat exchange in the electron gas and the metal lattice. A key issue in the application of this model is the proper description of temperature dependent thermophysical parameters of the material considered and this problem is discussed here. In this part the determination of metal lattice thermophysical parameters is presented.

6

The Dehydrogenation Process of Destabilized NaBH4-MgH2 Solid State Hydrie Composites

Czujko T., Varin R. A., Zarański Z., Wroński Z. S.

Archives of Metallurgy and Materials

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2010

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Vol. 55, iss. 2

539-552

EN

The composite behaviour of sodium borohydride – magnesium hydride mixtures was investigated. Mutual influence of both hydrides on their decomposition process was studied. The (NaBH4+MgH2) composite hydride system was synthesized in a wide range of compositions by controlled mechanical (ball) milling in a magneto-mill. In effect, nanocomposites having nanometric grain sizes of the constituent phases residing within micrometric-sized particles were produced. The dehydrogenation process of obtained composites was investigated by Differential Scanning Calorimetry (DSC) method. It is shown that the hydrogen desorption temperature of the composite constituent with the higher desorption temperature in the (NaBH4+MgH2) system substantially decreases linearly with increasing volume fraction of the constituent having lower desorption temperature which is similar behavior to well-known composite Rule-of-Mixtures (ROM) for structural composites. It is also shown that in the (NaBH4+MgH2) composite the constituents such as MgH2 and NaBH4 decompose separately and destabilization of the composite constituent with a higher desorption temperature is unrelated to the formation of MgB2 intermetallic phase. Therefore, the improved dehydrogenation properties for NaBH4 is likely due to the presence of nanostructured metallic Mg which acts as a catalyst. It is also shown that, most likely, the NaBH4 constituent act as a catalyst for the accelerated decomposition of MgH2.

PL

W pracy przedstawiono wyniki badań zachowań kompozytowch mieszaniny borowodorek sodu – wodorek magnezu, gdzie ocenie poddano wzajemne oddziaływanie obu wodorków na ich proces dekompozycji. Układ kompozytów wodorkowych (NaBH4+MgH2) syntetyzowany był w szerokim zakresie składów, poprzez kontrolowane mielenie mechaniczne (kulowe), w młynku magnetycznym. W efekcie powyższego procesu wytworzono nanokompozyty, których składniki fazowe posiadają ziarna o nanometrycznej wielkości, wystepujące w mikrometrycznych cząstkach. Proces odwodorowania uzyskanych kompozytów badano z wykorzystaniem metody kalorymetrycznej DSC (Differential Scanning Calorimetry). Wykazano, że temperatura desorbcji wodoru składnika kompozytu o wyższej temperaturze dekompozycji w układzie (NaBH4+MgH2) istotnie obniża się liniowo wraz ze wzrostem udziału objętościowego składnika o niższej temperaturze dekompozycji, zachowując się w sposób podobny do obowiazującej dla kompozytów strukturalnych reguły mieszanin ROM (Rule-of-Mixtures). Wykazano ponadto, iż w kompozycie (NaBH4+MgH2) jego składniki, MgH2 i NaBH4, dekomponuja oddzielnie i destabilizacja składnika o wyższej temperaturze desorbcji nie jest związana z powstawaniem fazy międzymetalicznej MgB2. Stąd też poprawa właściwości do odwodorowania NaBH4 jest prawdopodobnie spowodowana obecnoącią nanostrukturalnego, metalicznego Mg, który działa katalitycznie. Dodatkowo wykazano, że NaBH4 najprawdopodobniej działa katalitycznie na przyspieszenie dekompozycji MgH2.

7

Structural and mechanical properties of ZnTe in the zincblende phase

Soykan C., Ozdemir Kart S., Cagin T.

Archives of Materials Science and Engineering

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2010

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Vol. 46, nr 2

115-119

EN

Purpose: The aim of this work investigate to the structural and mechanical properties of ZnTe in the B3 structure, using the ab initio method based on Density Functional Theory (DFT). Design/methodology/approach: The Vienna ab initio Simulation Package (VASP) has been used to perform the electronic structure calculations. The projector-augmented wave formalism (PAW) implemented in this package leads to very accurate result comparable to other all-electron methods. The electronic exchange and correlation functions are treated within DFT by using generalized gradient approximation. Findings: The lattice parameter, bulk modulus, it's pressure derivative and the elastic stiffness coefficients are calculated. Our results for the structural parameters and the elastic constants at the equilibrium phase are in good agreement with the available experimental and other theoretical studies. We have also investigated the pressure dependence of mechanical properties for ZnTe in the structure of B3 to see this effect. Research limitations/implications: These compounds are convenient for many technological applications because of they have direct energy band gaps and property of light emitters at room temperature. Practical implications: These compounds used to many technological applications, such as solid state laser devices, photovoltaic devices, solar cells, remote control systems, thin films, transistors, THz emitter, detector and imaging systems etc. Originality/value: In this work, determination of structural and mechanical properties of ZnTe in the B3 structure at high pressures will lead to new technological applications of these materials.

8

Properties of GdFeAl ternary compound in two crystallographic structures

Klimczak M, Talik E, Jarosz J, Mydlarz T

Materials Science Poland

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2008

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Vol. 26, No. 4

954--958

EN

Properties of the GdFeAl compound which crystallized in the cubic MgCu2-type structure as well as in hexagonal MgZn2-type structure were compared. The electrical resistivity, AC susceptibility and magnetization as a function of temperature revealed relatively high magnetic ordering temperature about 200 K. The differences in magnetization were observed for samples crystallizing in two different crystallographic structures. The magnetic moments measured at 4.2 K and up to140 kOe are very far from the magnetic moment value for free Gd ion. The magnetic moment values of cubic and hexagonal phases are 1.1 μB and 1.7μB, respectively.

9

Magnetic properties of Dy5Pd2 single crystal

Klimczak M., Talik E., Kusz J., Hofmeister W., Winiarski A., Troć R.

Materials Science Poland

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2007

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Vol. 25, No. 2

263--267

EN

Thermal variation of the lattice parameters, magnetic susceptibility and magnetization of a Dy5Pd2 single crystal has been measured. The single crystal obtained by the Czochralski method crystallized in the cubic Dy5Pd2 type structure. The compound exhibits two characteristic temperatures. The former equals about 40 K, and the latter about 20 K, being connected with the complex ordering of the rare earth sublattice and the reorientation process of the magnetic moments, respectively.

10

Phase Equilibria in the Cu2S-{Sb,Bi}2S3-Ga2S3 and Cu2S-{Sb,Bi}2S3-In2S3 Systems at 673 K

Olekseyuk I., Zhbankov O., Kumanska Y., Tkachuk V.

Polish Journal of Chemistry

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2006

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Vol. 80, nr 5

817-823

EN

Phase equilibria in the Cu2S-{Sb,Bi}2S3-Ga2S3 and Cu2S-{Sb,Bi}2S3-In2S3 systems at 673 K were investigated by X-ray powder diffraction and their isothermal sections were constructed. No quaternary compounds or continuous solid solutions were found. The homogeneity region of the CuIn5S8 phase in quasibinary Cu2S-In2S3 system was determined in the range 7.3-17.2mol.% Cu2S. The Rietveld refinement of the crystal structure CuGa5S8 has been performed, using powder diffraction pattern in the zinc blende model (SG F43m, a = 0.52246(2) nm).

11

Wyznaczanie parametrów sieci krystalicznej metodą dyfrakcji zbieżnej wiązki elektronów (CBED)

Gigla M., Pączkowski P., Kostka A., Prusik K., Morawiec H.

Archiwum Nauki o Materiałach

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2003

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T. 24, nr 2

113-127

PL

Metoda dyfrakcji zbieżnej wiązki elektronów została zastosowana do wyznaczania parametrów sieci krystalicznej. Dzięki zastosowaniu unikalnego programu komputerowego, osiągnięto dobrą dokładność wynoszącą 0,00025 nm. Automatyczna detekcja pozycji linii HOLZ na eksperymentalnych obrazach CBED w oparciu o transformatę Hough'a, pozwoliła na skrócenie czasu analizy, a w szczególności, na osiągnięcie sub-pikselowej precyzji wyznaczenia położenia tych linii. Użycie w eksperymencie orientacji osi pasów o wysokich wskaźnikach hkl umożliwiło pominięcie niezwykle czasochłonnych - dynamicznych symulacji obrazów CBED.

EN

The CBED method was used for determination of the lattice parameters of a silicon single crystal. A computer program written for this application allow to achieve a good accuracy of 0.00025 nm. The Hough transform was applied for detection of the HOLZ line positions on the experimental CBED patterns, with the sub-pixels precision. In the experiment the high hkl indices CBED patterns were used, which allowed to omit the time consuming dynamical simulations of the CBED patterns.

12

Phase Equilibria in the AgGaS2-GeS2 Systems

Olekseyuk I., Gorgut G. P., Shevtchuk M. V.

Polish Journal of Chemistry

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2002

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Vol. 76 / nr 7

915-919

EN

The AgGaS2-GeS2 section has been investigated using the methods of physico-chemical analyses. The existence of _-tetragonal, _-monoclinic solid solutions on the basis of the initial compounds and the intermediate _-phase, which crystallizes in Fdd2 space group, has been established. The _-phase forms the eutectics with the initial components. Their coordinates are: 42 mol.% GeS2 (1121 K) and 93 mol.% GeS2 (1095 K).

13

Growth and characterisation of single crystals of ternary chalcogenides for laser applications

Isaenko L., Yelisseyev A., Zondy J. J., Knippels G., Thenot I., Lobanov S.

Opto-Electronics Review

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2001

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Vol. 9, No. 2

135-141

EN

Bulk single crystals up to 20 mm in diameter and 40 mm long for LiInS₂ and up to 10 mm, 20 mm, respectively, for LiInSe₂ have been grown. Their colour changed from colourless to rose for the first one and from yellow to dark red for the other. All crystals have wurtzite-type lattice (Pna21 space group), lattice parameters were determined. A band gap was found to be 3.72 and 3.57 eV for LiInS₂ and 3.02, 2.86 eV for LiInSe₂ at 80 and 300 K, respectively. Colour variations are due to point defects, first of all to interstitial sulfur, resulting in additional wide absorption bands in the shortwave part of transparency range. For LiInS₂ the SHG phase matching conditions were found to he similar for samples of different colour and some difference from Boyd’s predictions of 1973 was shown: for XY plane Dj~ +3° at 2.6 mm and Dj~ -3° at 4-5 mm. Nonlinear susceptibility for LiInS₂ was estimated: deff(XY) ~3.4 pm/V relative to Boyd’s value as 10.6 pm/V. A proper illumination gives a photoinduced change of LiInSe₂ colour from dark red to yellow as a result of changes in point defects charge state.

14

The phase equilibria on AgGaS2/AgInS2/-HgS section in the quasi-ternary Ag2S-HgS-Ga2S3/In2S3/ systems

Olekseyuk I., Galka V., Parasyuk O.

Polish Journal of Chemistry

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1999

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vol. 73 nr 2

255-261

EN

The phase diagrams of AgGaS2/AgInS2/-HgS sections in the quasi-ternary Ag2S-HgS-Ga2S3/In2S3/ systems have been constructed using differential thermal, X-ray phase and microstructural analyses. AgGaS2-HgS section is quasi-binary and belongs to the eutectic type. The coordinates of the eutectic point are 76 mol% HgS and 1018 K. AgInS2-HgS is not quasi-binary above the solidus. In the AgInS2-HgS system the limited solid solutions within the composition range 0-2 mol% HgS and 82-98 mol% HgS at 670 K were discovered. The compounds AgInS2 and HgS form limited solid solutions within the composition range 0-2 mol% HgS and 71-95 mol% HgS at 670 K. The solid solutions, in the part HgS-rich, are created on the basis of the low temperature cubic structure (a-HgS) on both sections.

15

Phase relations in the CuGaTe2-HgTe and CuInTe2-HgTe systems

Parasyuk O., Olekseyuk I., Morenko A., Gorgut G.

Polish Journal of Chemistry

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1999

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vol. 73 nr 5

765-771

EN

Phase equilibria in the CuGaTe2-HgTe and CuInTe2-HgTe systems are investigated by differential thermal, X-ray phase and microstructural analyses. Both systems are of quasibinary, peritectic type, resulting in the formation of solid solutions. Solid solubility in HgTe varies from 0-31 mol% for Cu GaTe2 and from 0-64 mol% for CuInTe2. The solid solution based on CuInTe2 does not exceed 4mol% HgTe and the one based on CuGaTe2 contains less than 2 mol% HgTe.

16

Phase relations in the Cu2Si(Ge,Sn)Te3-HgTe systems

Parasyuk O.V.

Polish Journal of Chemistry

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1998

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Vol. 72, nr 11

2440-2449

EN

The Cu2Si(Ge,Sn)Te3-HgTe systems were investigated using differential thermal, X-ray phase and microstructural analysis. Existence of the quaternary Cu2HgSiTe4 and Cu2HgGeTe4 phases, which melt congruently at 898 and 805 K respectively, have been established in Cu2SiTe3-HgTe and Cu2GeTe3-HgTe systems. The Cu2HgSnTe4 phase is a part of solid solution on the basis of Cu2SnTe3 in Cu2SnTe3-HgTe section. The solid solution on the basis of Cu2SiTe3 contains 7 mol% HgTe and the one on the basis of Cu2GeTe3 contains 12 mol% HgTe. The solid solubility in HgTe at 670 K is 2.5 mol% Cu2SiTe3, 4 mol% Cu2GeTe3, and 5.5 mol% Cu2SnTe3.