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PL
Taśmy stopu Ti50Ni25Cu25 wytworzono metodą szybkiego chłodzenia z fazy ciekłej z zastosowaniem pojedynczego bębna chłodzącego ( melt-spinning). Odlano dwie taśmy stopu w następujących warunkach temperatury ciekłego stopu i prędkości bębna chłodzącego, odpowiednio: 1255°C i 19 m/s oraz 1352°C i 23 m/s. Wytworzone taśmy cechują duże różnice w stopniu krystaliczności. Taśma odlana w warunkach temperatury ciekłego stopu 1352°C i prędkości bębna chłodzącego 23 m/s jest w stanie amorficznym z niewielką zawartością obszarów krystalicznych z płytkami martenzytu. Płytki martenzytu pełnią rolę zarodków podczas dalszej krystalizacji w temperaturze powyżej 466°C. W stanie krystalicznym obie taśmy wykazywały jednokierunkowy efekt pamięci kształtu oraz zjawisko nadsprężystości. Taśmę odlaną z temperatury 1255°C dodatkowo wygrzewano w temperaturze 200°C przez 0,5 h. Uzyskano zwiększenie objętości względnej ziaren zorientowanych zgodnie z kierunkiem <011>. Kierunek ten jest kierunkiem uprzywilejowanym podczas tworzenia się martenzytu. Zabieg przyczynił się do zwiększenia efektu pamięci kształtu do wartości 3,5%.
EN
The Ti50Ni25Cu25 alloy was produced in the form of thin ribbons using the melt-spinning technique. Two ribbons were cast by applying the following processing parameters: temperature of liquid alloy 1255°C and wheel speed of 19 m/s as well as temperature of 1352°C and wheel speed of 23 m/s. The ribbons revealed significant differences in their crystallinity. The ribbon cast using a higher value of processing parameters was mainly amorphous with a small number of areas with martensite plates inside. These crystalline areas played the role of crystal nuclei during the crystallization process at temperatures above 466°C. The crystalline ribbons demonstrated the on-way shape memory effect as well as pseudoelastic effect. The ribbon cast at 1255°C was additionally annealed at 200°C for 30 minutes. Thermal treatment caused an increase in grains, which were textured along the <011> direction. This direction is favourable when inducing the reversible martensitic transformation. Such grains formation was a source of shape memory increase up to 3.5%.
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Content available remote Structure of laser treated multicrystalline silicon wafers
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EN
Purpose: The aim of the paper is to demonstrate influence of laser processing on multicrystalline silicon. This process is applied for texturization of solar cells. Design/methodology/approach: Evaluation of results was performed by transmission electron microscope (TEM). Findings: Performed experiments revealed that laser processing may introduce linear defects in crystallographic structure of silicon. Additionally, it was found that this kind of processing produces thin amorphous layer. Research limitations/implications: Laser scribing introduces defects. It is important to characterize their influence on the electrical properties of silicon solar cells. It is possible to remove these defects by means of chemical etching. Practical implications: The research presented in the paper was carried out to incorporate elaborated method into manufacturing process of solar cells of reduced reflectance from the front surface. Success of research is expected to lead to higher efficiency solar cells. Originality/value: value of the paper lies in finding attractive method for efficient texturization of multicrystalline silicon.
4
Content available remote TEM investigations of laser texturized polycrystalline silicon solar cell
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EN
Purpose: The presented in this paper research results concern investigation of phase transformation of the surface structure of polycrystalline silicon solar cell. The surface of boron doped polycrystalline silicon wafers were texturised by means of diode-pumped pulsed neodymium-doped yttrium aluminium garnet laser crystal (Nd:YAG). Investigations were carried out on transmission electron microscope (TEM) to observe the changes that occurred after laser treatment of the surface layer. Changes in microstructure of the surface layer of solar cells under the influence of the laser beam are presented using the analysis phase and dislocations present in the microstructure. Observations were carried out on prepared thin foils. Moreover, diffraction patterns from selected regions of textured wafers were solved to qualify phase transformations under influence of laser beam. Design/methodology/approach: Investigations were carried out on the Transmission Electron Microscope JEM 3010 supplied by JEOL with 300 kV accelerating voltage equipped with an electronic camera configured with a computer. The microstructure was obtained in the bright field image as well dark field working in a magnification range of 10000x to ca. 100000x. Phases identification was performed by means of selected area diffraction (SAD) method, where for diffraction pattern calculations the computer software “Eldyf” was used, kindly supplied by the Institute of Materials Science, University of Silesia. Findings: The research included analyze of the influence of laser treatment conditions on geometry, roughness and size of laser made surface texture of silicon wafer applied for solar cells. Research limitations/implications: Paper contributes to research on silicon surface processing using laser beam. Practical implications: Conducted investigations may be applied in optimisation process of solar cell surface processing. Originality/value: The range of possible applications increases for example as materials for solar cells placed on building constructions, elements in electronics and construction parts in automobile industry.
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EN
Purpose: In this work there are presented the investigation results of mechanical properties and microstructure of the hot work tool steel 32CrMoV12-28 alloyed with oxide powders like aluminium oxide and zirconium oxide. The purpose of this work was also to determine the laser treatment conditions for surface hardening of the investigation alloys with appliance of transmission electron microscopy. Design/methodology/approach: The investigations were performed using optical microscopy for the microstructure determination. By mind of the transmission electron microscopy the high resolution and phase determination was possible to obtain. The morphology of the ceramic powder particles was studied as well the lattice parameters for the Fe matrix and phase identification using diffraction methods was applied. Findings: After the laser alloying of the hot work tool steel with the selected oxide powders the structure of the samples changes in a way, that there are zones detected like the remelting zone the heat influence zone where the grains are larger and not so uniform as in the metal matrix. The used oxide powders are not present after the laser treatment in the steel matrix. Research limitations/implications: The investigated steel samples were examined metallographically using optical microscope with different image techniques, SEM, TEM and analyzed using a Rockwell hardness tester, also EDS microanalysis and electron diffraction with Fourier transform was made. Practical implications: As an implication for the practice a new technology can be possible to develop, based no diode laser usage. Some other investigation should be performed in the future, but the knowledge found in this research shows an interesting investigation direction. Originality/value: The combination of TEM investigation for laser alloying of hot work tool steels makes the investigation very attractive for automotive and other heavy industries.
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PL
Mikrostruktura i własności granicy rozdziału faz w kompozycie Al-TiB2 otrzymanego metodą SHSB (Self-Propagating High-temperature Synthesis Bath) były przedmiotem badań z zastosowaniem transmisyjnej mikroskopii elektronowej. Naprężenia wewnętrzne osnowy w pobliżu cząstek TiB2 badano, używając do tego celu metody zbieżnej wiązki dyfrakcyjnej. Analiza linii HOLZ z obrazów CBED umożliwiła pomiar parametrów komórki elementarnej. Pozwoliło to określić rozkład pól naprężeń i umocnienia w obszarze granicy rozdziału faz.
EN
The interface microstructure of AI-TiB2 composite was studied using the SEM, HREM, CBED and X-ray phase analyses. The micrograph of the studied composite (Fig. 1) shows homogenous arrangement of the TiB2 particles in aluminum matrix. The matrix show presence of relatively high dislocation density (Fig. 2). Some strongly refined phase were observed (Fig. 3). Fast Fourier transform of the HREM image obtained from that phase (Fig. 4) show that it can be strongly refined phase of titanium-boron. HREM images of the interface (Fig. 5) of the composite, after the computer processing, exhibit dislocation presence. The local strength of the matrix was investigated near the TiB2 particles, using TEM at CBED mode. Figure 6 shows studied area with well visible dots of the CBED measurement. Analyses of the HOLZ lines from CBED diffraction patterns (Fig. 7) allowed to determine changes of the lattice constant versus interface distance (Fig. 8).
EN
Structure and thus properties of melt-spun CuAlNi-based alloys are mainly affected by the wheel speed and additional heat treatment. Increase in the wheel speed causes increase of the quenched-in vacancy concentration, grain refinement, rise of the columnar morphology and their privileged orientation. The texture, which becomes sharpener with the wheel speed increase, consists of a fibre [100] orientation and two sheet component orientations (100)<001> and (100)<011> related to the DO3-parent phase. The latter component increases after annealing the ribbons at 900 degrees centigrade. The reversible elongation during transformation under constant stress increases with the texture development. It also increases with increasing the load under which the shape recovery was measured. Effect of all these factors on shape memory and mechanical properties will be considered in the presented paper.
PL
Struktura i własności taśm ze stopów Cu-Al-Ni otrzymanych przez szybkie oziębianie strugi ciekłego metalu na wirującym bębnie zależą głównie od szybkości obrotowej bębna i następnej obróbki cieplnej. Wzrost szybkości powoduje zwiększenie stężenia zamrożonych wakansów i zniekształceń sieciowych, silne rozdrobnienie ziarna, powstanie kolumnowej budowy ziaren i związanej z tym tekstury. Tekstura taśm wykazuje obecności orientacji osiowej [100] oraz składowych tekstury taśm: (100)<001> i (100)<011> odnoszonych do sieci fazy macierzystej DO3. Wyżarzanie w T=900 degrees centigrade powoduje znaczący wzrost składowych orientacji taśm. Efekt pamięci kształtu - jako zmiana wydłużenia pod stałym naprężeniem w procesie odwracalnej przemiany martenzytycznej związany jest z intensywnością występującej tekstury. W artykule rozważany jest wpływ czynników kształtujących strukturę i własności mechaniczne.
EN
The microstructure of amorphous and nanocrystalline Fe42.7Co42.7Zr6.8-xNbxB6.8Cu1 (x = 0 or 1) alloys was investigated. We have stated that the nanocrystalline samples consist of the crystalline alfa-FeCo grains about 8 nm in diameter embedded in an amorphous matrix which is rich in cobalt. From Mössbauer spectroscopy studies we have found that the crystalline alfa-FeCo phase in the nanocrystalline samples obtained by the conventional annealing is atomically ordered. Moreover, the order degree depends on the annealing time. As for the samples partially crystallized during rapid quenching, the crystalline alfa-FeCo phase is atomically disordered.
PL
W pracy przeprowadzono badania nanokrystalizacji oraz własności magnetycznych, takich jak podatność i jej dezakomodacja stopów: Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 lub 1). Stwierdzono, że w początkowym stadium krystalizacji stopów Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 lub 1) zawartość żelaza w osnowie amorficznej nie ulega zmianie, obserwuje się natomiast zmniejszenie koncentracji żelaza w fazie przejściowej, co spowodowane jest dyfuzją atomów boru i cyrkonu na zewnątrz obszarów, w których fomują się ziarna fazy krystalicznej. Pomimo tego, część atomów boru i cyrkonu pozostaje w fazie krystalicznej i dlatego koncentracja żelaza w fazie alfa-Fe zależy od warunków obróbki cieplnej i rośnie z temperaturą wygrzewania. Stopy Fe85,4Zr6,8-xMexB6,8Cu1 w stanie amorficznym charakteryzują się małą wartością podatności magnetycznej i dużym natężeniem dezakomodacji. Największą wartość początkowej podatności magnetycznej (8500 w temperaturze pokojowej) wykazuje typ nanokrystaliczny Fe85,4Zr5,8Nb1B6,8Cu1.
EN
In this paper, investigations of nanocrystallization and magnetic properties, i.e. the initial magnetic susceptibility and its disaccommodation of the Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) alloys were performed. It has been stated that in the early stages of crystallization of the Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) the iron concentration in the amorphous matrix is the same as in the as-quenched state. However, the decrease of iron concentration in the interfacial zone is observed, which is connected with diffusion of B and Zr atoms out of regions where grains are created. In spite of it, part of these atoms remains in alpha-Fe phase. Therefore, the iron concentration in alpha-Fe phase depends on heat treatment conditions and increases with annealing temperature. The Fe85,4Zr6,8-xMexB6,8Cu1 (Me=Nb, Mo, Nd, x=0 or 1) alloys in the amorphous state exhibit the low initial magnetic susceptibility and high intensity of disaccomodation. After partial crystallization of those alloys the largest initial magnetic susceptibility (8500 at room temperature) was found for the nanocrystalline Fe85,4Zr5,8Nb1B6,8Cu1 alloy.
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