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Search results for: materials science
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Biocompatibility and bioactivity of load-bearing metallic implants
PublicationThe main objective of here presented research is to develop the titanium (Ti) alloy base composite materials possessing better biocompatibility, longer lifetime and bioactivity behaviour for load-bearing implants, e.g. hip joint and knee joint endoprosthesis. The development of such materials is performed through: modeling the material behaviour in biological environment in long time and developing of new procedures for such evaluation;...
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Cavitation erosion degradation of Belzona® coatings
PublicationIn hydrocarbon and maritime industry there is a constant need of materials and coatings withstanding severe conditions. One of adverse phenomena present there is cavitation erosion. The paper presents evaluation of cavitation resistance of three different steel coatings. Belzona 2141 (ACR-Fluid Elastormer), 1321 (Ceramic S-Steal) and 5831 (ST-Barrier) were deployed on P110 steel and subjected to ultrasound cavitation in distilled...
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Cavitation Erosion Resistance Influence of Material Properties
PublicationThe cavitation erosion is the phenomena that causes degradation of fluid flow machinery components due to repetitive implosion of cavitation bubbles adjacent to the solid surface. Cavitation erosion is a complex phenomenon, which includes not only hydrodynamic factors of liquid, but also properties of erodible material e.g. microstructure, hardness or Young modulus. In order to reduce the negative impact of erosion on machine components,...
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Applying molecular dynamics simulation to take the fracture fingerprint of polycrystalline SiC nanosheets
PublicationGraphene-like nanosheets are the key elements of advanced materials and systems. The mechanical behavior of the structurally perfect 2D nanostructures is well documented, but that of polycrystalline ones is less understood. Herein, we applied molecular dynamics simulation (MDS) to take the fracture fingerprint of polycrystalline SiC nanosheets (PSiCNS), where monocrystalline SiC nanosheets (MSiCNS) was the reference nanosheet....
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Negative Poisson’s ratio from pentagons: A new auxetic structure combining three different auxetic mechanisms
PublicationA novel class of two-dimensional auxetic structures based on the pentagon motif is proposed. Their mechanical properties are investigated by combining molecular mechanics simulations with a simple three-parameter mechanical model which assumes perfectly elastic behavior. It is predicted that the proposed structures – termed as double re-entrant honeycomb – may possess unique mechanical characteristics, which include complete and...
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Frequency bands selection of the Portevin–LeChatelier effect
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Mechanical, Structural and Diffusion Studies of Hydrogel Polyurethane Nanocomposites Containing Modified Montmorillonite
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Optimization of biocorrosion resistance and mechanical properties of PM Ti–XAl–2Fe–3Cu alloys by response surface methodology
PublicationIn the current study, the biocorrosion resistance and mechanical properties of the Ti–XAl–2Fe–3Cu (wt%) (X = 6, 4, 2 wt%) alloy produced by powder compact extrusion of blended elemental powders were optimized by using the response surface methodology in order to gain the best combination of processing parameters. To run the optimization process, central composite design with three equal levels of oxygen, hydrogen and aluminum was...
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Gas Composition Influence on the Properties of Boron-Doped Diamond Films Deposited on the Fused Silica
PublicationThe main subject of this study are molecular structures and optical properties of boron-doped diamond films with [B]/[C] ppm ratio between 1000 and 10 000, fabricated in two molar ratios of CH 4 -H 2 mixture (1 % and 4 %). Boron-doped diamond (BDD) film on the fused silica was presented as a conductive coating for optical and electronic purposes. The scanning electron microscopy images showed homogenous and polycrystalline surface...
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The unstable thermoelectric effect in non-stoichiometric Cu2Se during the non-equilibrium phase transition
PublicationThe superionic α ↔ β phase transition in Cu1.96Se thermoelectric material is investigated by means of thermal analysis (DSC) and measurements of Seebeck coefficient and electrical conductivity. Results of the DSC measurements with 1–10 K/min heating and cooling rates show that the material is close to the equilibrium phase composition during the transformation. However, the kinetic limitation of the process exists, which is indicated...
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Microstructure and mechanical properties of laser surface-treated Ti13nb13zr alloy with MWCNTs coatings
PublicationLaser surface modification of titanium alloys is one of the main methods of improving the properties of titanium alloys used in implantology. This study investigates the microstructural morphology of a laser-modified surface layer on a Ti13Nb13Zr alloy with and without a carbon nanotube coating deposited by electrophoretic deposition. Laser modification was performed for samples with and without carbon nanotube coating for two...
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Mechanism of hopping conduction in Be–Fe–Al–Te–O semiconducting glasses and glass–ceramics
PublicationElectrical properties of beryllium-alumino-tellurite glasses and glass–ceramics doped with iron ions were studied using impedance spectroscopy. The conductivity was measured over a wide frequency range from 10 mHz to 1 MHz and the temperature range from 213 to 473 K. The D.C. conductivity values showed a correlation with the Fe-ion concentration and ratio of iron ions on different valence states in the samples. On the basis of...
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Assessment of Corrosive Behaviour and Microstructure Characterization of Hybrid Friction Stir Welded Martensitic Stainless Steel
PublicationThis study examined the effect of induction heating on the microstructure and corrosion characteristics of hybrid friction stir welded AISI 410 stainless steel. Five joints have been produced with different friction stir welding parameters like welding speed, spindle speed, plunge depth, and induction power. Their microstructures were evaluated using a scanning electron microscope, and chemical composition was examined using...
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Electrocatalytic oxidation of methanol, ethylene glycol and glycerine in alkaline media on TiO2 nanotubes decorated with AuCu nanoparticles for an application in fuel cells
PublicationIn this work, we present the catalytic and photocatalytic activity of AuCu nanostructures obtained on TiO2 nanotubes toward methanol, ethylene glycol and glycerine oxidation. The electrode material is prepared by anodization of Ti foil, thin AuCu layer sputtering and rapid thermal treatment under argon atmosphere. Scanning electron microscopy images confirmed the presence of ordered tubular architecture of TiO2 as well as nanoparticles...
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Generalized Einstein relation in disordered organic semiconductors: Influence of the acoustic phonons–charge carriers scattering
PublicationIn this work, we analyze the generalized Einstein relation for disordered organic semiconductors with a non-equilibrium Druyvesteyn-type distribution function. The Druyvesteyn behavior of hot electrons in a solid state is associated with the acoustic phonons–charge carriers scattering. Such a case has been experimentally demonstrated in electroluminescent inorganic rare–earth–doped zinc chalcogenides. Therefore, we can assume that,...
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The effect of low energy impact on the tensile strength of coated and uncoated glass particulate composites.
PublicationPrzedstawiono model teoretyczny pozwalający przewidywać poudarową wytrzymałość na rozciąganie w funkcji parametrów materiałowych i budowy kompozytu. Określono eksperymentalnie poudarową wytrzymałość na ściskanie kompozytów zbrojonych ciągłym włóknem szklanym w osnowie żywicy epoksydowej napełnianej mikrokulkami szklanymi w celu obniżenia skłonności do powstawania dużych zniszczeń przy udarze o niskiej energii. Wyniki eksperymentalnie...
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Hydrogen-enhanced stress corrosion cracking and corrosion fatigue of HSLA steels in sea-water
PublicationPrzedstawiono ocenę podatności stali o wysokiej wytrzymałości na naprężeniowe pękanie korozyjne i zmęczenie korozyjne wspomagane przez wodór. Wykonano próby powolnego rozciągania i zmęczenia niskoczęstotliwościowego na stalach 17HMBVA i 14HNMBCu oraz ich złączach spawanych, w środowisku wody morskiej, przy polaryzacji katodowej. Zamieszczono wyniki badań elektrochemicznych oraz przełomów na skaningowym mikroskopie elektronowym.
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Post-impact moisture absorption in hybrid glass, aramid, carbon/epoxy composites
PublicationZbadano chłonność wody i własności po udarze i absorpcji wody w laminatach hybrydowych aramidowo-szklano-węglowych. Badania porównawcze dla laminatów szklano-epoksydowych wykazały 18% i 33% spadek wytrzymałości na ściskanie odpowiednio w wyniku udaru o energii 10J oraz udaru i absorpcji wody.
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Cavitation erosion of heterogeneous thin coatings produced by means of laser cladding
PublicationPrzedstawiono badania odporności kawitacyjnej cienkich heterogenicznych warstw nakładanych metodami laserowymi na stal 45. Wykazano dobrą przyczepność i wysoką odporność kawitacyjną wykonanych powłok.
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Laser surface treatment of aluminium-silicon alloy at cryogenic conditions
PublicationW artykule przedstawiono wpływ laserowego, powierzchniowego przetapiania w warunkach kriogenicznych na mikrostrukturę, mikrotwardość, zużycie na skutek tarcia oraz korozję stopu aluminium AlSi13Mg1CuNi. Stwierdzono zwiększenie mikrotwardości, odporności na ścieranie i korozję odlewniczego stopu AlSi13Mg1CuNi stosowanego w produkcji tłoków silników spalinowych.
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Advanced vanadium modified steels for high pressure hydrogen reactors
PublicationPrzedstawiono nową generację stali chromowo-molibdenowych zmodyfikowanych wanadem, przeznaczonych do budowy wodorowych reaktorów i porównano ze stalami konwencjonalnymi. Opisano mikrostrukturę, właściwości i zastosowanie stali. Podkreślono wpływ mikrostruktury nowych stali na przebieg degradacji środowiskowej.
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Microstructure and wear of cast aluminium alloy with laser modified surface layer
Publicationprzedstawiono wyniki badań zużycia przez tarcie przetopionego laserowo stopuAlSi13MgCuNi w warunkach tribologicznych. Wykazano, iż zużycie i współczyn-nik tarcia są zależne od parametrów obróbki laserowej w warunkach kriogeni-cznych.
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Propagation of elestic waves in beams including damping effects.
PublicationW pracy przedstawiono wyniki analizy propagacji fali sprężystej w belce z tłumieniem wiskotycznym.
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Spectral plate element for crach detection with use of propagation wares.
PublicationW pracy przedstawiono model płyty oparty na metodzie elementów spectralnych. Przedstawiono wyniki analizy interakcji pęknięcia zmęczeniowego i propagującej się fali.
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Evaluation of drawability of tailor-welded blanks made of titanium alloys Grade 2 || Grade 5
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Temperature distribution in laser-clad multi-layers
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Fabrication of Composite Polyurethane/Hydroxyapatite Scaffolds Using Solvent-Casting Salt Leaching Technique
PublicationScaffolds are porous three-dimensional structures which are used to fill bone losses and make them possible to cells to grow. Many different structural and biological properties are required from them: porosity, mechanical strength and biocompability. The present research is aimed at development of composite polyurethane/hydroxyapatite scaffolds by using the solvent-casting salt leaching method. The SEM examinations were applied...
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Cold Cracking Of Underwater Wet Welded S355G10+N High Strength Steel
PublicationWater as the welding environment determines some essential problems influencing steel weldability. Underwater welding of high strength steel joints causes increase susceptibility to cold cracking, which is an effect of much faster heat transfer from the weld area and presence of diffusible hydrogen causing increased metal fragility. The paper evaluates the susceptibility to cold cracking of the high strength S355G10+N steel used,...
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Electrical properties of hybrid planar diode based on palladium phthalocyanine and titanium dioxide
PublicationThis work details experimental studies of a planar diode made of indium tin oxide/titanium dioxide/palladium phthalocyanine/gold. The rectification ratio of current was 105 at 1.5 V. The analysis of the electrical properties of the system was based on small signal complex capacitance spectra measured in the frequency range of 25 Hz-1 MHz at different values of bias. No depletion region at the TiO2/PdPc interface was observed. Forward...
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DYNAMIC MECHANICAL BEHAVIOUR OF GFRP COMPOSITES WITH SiO2 NANO PARTICLES REINFORCED EPOXY MATRIX
PublicationDynamic mechanic (DMA) tests were performed to compare the mechanical behaviour of glass fibre reinforced epoxy laminate composites with SiO2 nanoparticle reinforced matrix. The selection of the most promising nanoparticle concentrations was considered in terms of elastic modulus and glass transition temperature. The reference specimens (0% nanoparticles) did not contain diluent accordingly the results do not allow the exact comparison...
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Weldability of S500MC Steel in Underwater Conditions
PublicationWet welding with the use of covered electrodes is one of the methods of underwater welding. This method is the oldest, the most economic and the most versatile. The main difficulties during underwater wet welding are: high cooling rates of the joint, the presence of hydrogen in the arc area and formation of hard martensitic structure in the weld. These phenomena are often accompanied by porosity of welds and large number of spatters,...
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The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints
PublicationThe tests results of superduplex stainless steel welded joints made with a different heat input, using automatic submerged arc welding (SAW) and semi-automatic flux-cored arc welding (FCAW) have been presented. Metallographic examinations, the measurements of the ferrite content, the width of the heat affected zone (HAZ) and the hardness of the welds in characteristic areas have been performed. Significant differences in the amount of...
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Quadratic Cohen representations in spectral analysis of serration process in Al–Mg alloys
PublicationImportant from mechanical point of view the Portevin–Le Chatelier serration phenomenon is being characterized by a complicated spectral profile. As a typical example of nonstationary processes it demands a special treatment allowing to follow the evolution of energy of stress fluctuations as a function of strain. The authors suggest the utilization of a compact system of quadratic transformations, known as Cohen class, as a technique...
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Two-step synthesis of niobium doped Na–Ca–(Mg)–P–Si–O glasses
PublicationNiobium doped biosolubility glasses in the Na–Ca–(Mg)–P–Si–O system were prepared by using an untypical two-step synthesis route. The parent glass was melted in air atmosphere at 1350 °C followed by re-melting the glass in Nb crucible with the addition of metallic Mg/Ca powder in the nitrogen atmosphere. The second melting step was carried out at 1450–1650 °C, using an induction furnace. The topography and structure of the obtained...
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Influence of retrogression and reaging (RRA) heat treatment on microstructure, mechanical and chemical behaviour of an Al-Zn-Mg alloy
PublicationBadano metodą stałego wolnego rozciągania w wodzie morskiej wpływ czasu i temperatury nawrotu oraz powtórnego starzenia na czas do zniszczenia, energię zniszczenia, przewężenie i odkształcenie. Stwierdzono ogólnie niewielki wpływ, przy czym wzrostowi odporności na korozję naprężeniową towarzyszył spadek właściwości mechanicznych. Obserwowane zmiany właściwości przypisano zmianom struktury dyslokacyjnej i mikrostruktury.
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Relationship between cavitation resistance of laser produced alloys and their ability to work hardening
PublicationBadano odporność kawitacyjną laserowo wytworzonych stopów na stalach konstrukcyjnych i ich związek ze zdolnością do umacniania się pod wpływem działania obciążeń kawitacyjnych. Wykazano, że mikrotwardość powierzchni wykazuje monotoniczną zależność z odpornością kawitacyjną i zdolnością do umacniania.
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Dependence of cavitation performance of superficial iron alloys on the sub-strate
PublicationWykazano zależność odporności kawitacyjnej laserowo wytworzonych i elektrodąotuloną napawanych powłok od rodzaju podłoża. Napoiny wykonywano na stali 45, 2H13, 0H18N9 i na żelazie Armco.
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Hydrogen-enhanced stress corrosion cracking in low alloy steels in seawater
PublicationBadano podatność stali niskostopowych w wodzie morskiej w warunkach polaryzacji katodowej. Stwierdzono spadek czasu do zniszczenia, energii zniszczenia i przewężenia ze wzrostem potencjału katodowego. Wykazano znaczącą korelację między stopniem degradacji wodorowej a stężeniem wodoru dyfuzyjnego.
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Impact Behaviour of Glass Fribre /Epoxy Composites with Nano-Enhanced Resin after Water Exposure
PublicationImpact behaviour of glass fibre /epoxy composites with nano- SiO2 modified resin was studied in terms of low velocity impact after water exposure. Nanocomposites with 1%, 2%, 3% 5% 7% nano-SiO2 (Nanopox- Evonic) were investigated. Peak impact load and impact damage area as a function of nanoparticle contents were compared for dry specimens and for samples exposed to water (0.7 %wt. 1.7% water absorbed) at 1J, 2J 3J impact energies....
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ESTIMATION OF YOUNG`S MODULUS OF THE POROUS TITANIUM ALLOY WITH THE USE OF FEM PACKAGE
PublicationPorous structures made of metal or biopolymers with a structure similar in shape and mechanical properties to human bone can easily be produced by stereolithographic techniques, e.g. selective laser melting (SLM). Numerical methods, like Finite Element Method (FEM) have great potential in testing new scaffold designs, according to their mechanical properties before manufacturing, i.e. strength or stiffness. An example of such designs...
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Structure and thermal expansion of liquid bismuth
PublicationExperimental structural data for liquid Bi were used for estimation of the main structure parameters as well as the thermal expansion coefficient both in supercooled and superheated temperature ranges. It was shown that the equilibrium melt had a positive thermal expansion coefficient within a temperature range upon melting and a negative one at higher temperatures. The former was related to structure changes upon melting, whereas...
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Structure and properties of liquid Al–Cu alloys: Empirical potentials compared
PublicationWe report on the structure and mass transport properties of liquid Al–Cu alloys predicted by two recently-developed empirical many-body potentials: MEAM (Jelinek et al., 2012) and EAM-ADP (Apostol and Mishin, 2011), and by the well-known Gupta potential. Total and partial pair correlation functions, angular distribution functions, densities, coordination numbers and self-diffusion coefficients are compared with published experimental...
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On degradation of glass/polyester laminate immersed in water
PublicationMechanical behaviour was compared for glass/ polyester laminates manufactured in the boatbuilding plant using three methods: hand lay-up, vacuum bagging, infusion. Specimens were tested in dry condition and following accelerated water immersion test (70°C- corresponding to the exposure of 30 years at 19°C). In three point bending test 40-50% reduction in laminate strength was observed due to water immersion. The highest degradation...
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Mechanical, structural and diffusion studies of hydrogel polyurethane nanocomposites containing modified montmorillonite
PublicationW pracy zaprezentowano wyniki badań hydrożeli poliuretanowych zawierających poli(tlenek etylenu) oraz montmorylonit. Otrzymane układy scharakteryzowano z użyciem technik XRD, DMA, badań mechanicznych oraz wyznaczono chłonność wody i parametry dyfuzji.
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Corrosion resistance examinations of Ti6Al4V alloy with the use of potentiodynamic method in Ringer`s and artificial saliva solutions
PublicationThe research results of corrosion resistance of the Ti6Al4V alloy in the simulated body fluids (SBF) are presented. The polished specimens have shown better corrosion resistance than grinded surfaces in both liquids. The artificial saliva has revealed more aggressive test solution than Ringer`s solution. The pitting tendency has been observed in Ringer`s solution for grinded specimens.
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Low velocity impact damage in glass/polyester composite sandwich panels
PublicationZbadano odporność udarową konstrukcji przekładkowych z laminatu poliestrowo szklanego pod kątem adhezji z rdzeniem (pianki PVC) przy polaczeniu dwoma rodzajami kleju lub łączanymi na ''mokro'' przy pomocy żywicy w trakcie utwardzania laminatu. Do oceny obszaru zniszczeń udarowych zastosowano metodę ultradźwiękową, która umożliwia wykrycie pola delaminacji nakładających się na siebie w poszczególnych warstwach .Obszary zniszczeń...
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Environmental degradation of the Cr-Mo steels in liquid hydrocarbons
PublicationPrzedstawiono podatność stali stopwych 26H2MF i 34HNM do naprężeniowego pękania korozyjnego. Środowiskiem do badań było paliwo ciężkie i zużyty olej mineralny.
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Processing of porous structures of YBa2Cu3O7-δ High-temperature superconductor
PublicationPublikacja opisuje technikę otrzymywania nadprzewodnika wysokotemperaturowego YBa2Cu3O7-x o porach otwartych.
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Influence of conditions of synthesis on superconductivity in Nd2-xCexCuO4-y
PublicationPróbki Nd1.85Ce0.15CuO4 uzyskano dwoma różnymi metodami syntez. Po procesie redukcji właściwości nadprzewodzące próbek scharakteryzowano za pomocą pomiarów rezystywnych i magnetycznych. W celu przeanalizowania morfologii powierzchni próbek poddano je badaniom mikroskopowym SEM z sondą EDAX.
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New laser-enhanced surface treatment of Ti bioalloy
PublicationPrzedstawiono wyniki badan mikrostruktury i korozji w roztworze Ringera stopu Ti6Al4V, który był poddawany nadtapianiu laserem CO2 w powietrzu, wodzie i ciekłym azocie. Stwierdzono znaczący wpływ warunków obróbki na mikrostrukturę, mikrotwardość i głębokość zmodyfikowanej warstwy wierzchniej.