Filtry
wszystkich: 400
wybranych: 361
Wyniki wyszukiwania dla: MICORSTRUCTURE
-
A Quantitative Investigation of Dislocation Density in an Al Matrix Composite Produced by a Combination of Micro-/Macro-Rolling
PublikacjaAn aluminum matrix composite with dispersed carbon nanotubes (CNTs) was produced via flake powder metallurgy using a micro-rolling process and vacuum hot pressing (VHP), followed by conventional rolling using a macro-rolling process. The microstructure and mechanical properties of the produced composites were studied. In addition, a new quantitative model was introduced to study the dislocation density based on the microstructural...
-
Structure and thermoelectric properties of nickel-doped copper selenide synthesised in a hydrogen atmosphere
PublikacjaNickel-doped copper selenide—Cu2-xNixSe (x = 0; 0.01; 0.02; 0.03)—materials with high thermoelectric properties were synthesised through reduction of reagents in hydrogen. The impact of the nickel content on both the microstructure and thermoelectric properties was examined. The nickel-doped samples’ microstructure differed significantly from pristine copper selenide. Besides Cu2Se, copper precipitations were present in the materials....
-
Selection of Electrode Material for Inconel 617/P92 Steel SMAW Dissimilar Welds
PublikacjaThe present work aimed to investigate the microstructure and mechanical properties of the dissimilar shielded metal arc welded (SMAW) joint of Alloy 617 and P92 steel for advanced ultrasupercritical boilers. The SMAW joint was produced using three different types of electrodes, namely, ENiCrFe-3, ENiCrMo-3, and ENiCrCoMo-1. During microstructural observation of the welded joints, no possible cracking was detected in the weldments....
-
Hydrogen-enhanced degradation and oxide effects in zirconium alloys for nuclear applications
PublikacjaThe zirconium alloys used in nuclear industry include mainly ZreSn and ZreNb alloys ofdifferent chemical composition, microstructure and susceptibility to both hydrogendegradation and oxidation. The hypothetic nuclear accidents can create a real danger tothe Zr alloys and stability of parts made of these alloys, and especially such as loss ofcoolant accident (LOCA) and reactivity initiated accidents (RIA). The hydrogen degradationcan...
-
Effects of Surface Pretreatment of Titanium Substrates on Properties of Electrophoretically Deposited Biopolymer Chitosan/Eudragit E 100 Coatings
PublikacjaThe preparation of the metal surface before coating application is fundamental in determining the properties of the coatings, particularly the roughness, adhesion, and corrosion resistance. In this work, chitosan/Eudragit E 100 (chit/EE100) were fabricated by electrophoretic deposition (EPD) and both their microstructure and properties were investigated. The present research is aimed at characterizing the effects of the surface...
-
Evaluation of reformer tubes degradation after long term operation
PublikacjaPurpose of this paper is to show the effect of long-term service at elevated temperatures on microstructural changes of cast steel reformer tubes made of the alloy IN-519 (24%Cr, 24%Ni, Nb). The relationship between mechanical properties and microstructure degradation is discussed. Investigations were performed on five tubes taken from ammonia reformer furnace. Tubes worked at temperature of 880C and 3,2 MPa pressure. The operation...
-
Laser Dissimilar Welding of AISI 430F and AISI 304 Stainless Steels
PublikacjaA dissimilar autogenous laser welded joint of AISI 430F (X12CrMoS17) martensitic stainless steel and AISI 304 (X5CrNi18-10) austenitic stainless steel was manufactured. The welded joint was examined by non-destructive visual testing and destructive testing by macro- and microscopic examination and hardness measurements. With reference to the ISO 13919-1 standard the welded joint was characterized by C level, due to the gas pores...
-
Proton-Electron Hole Interactions in Sr(Ti,Fe)O3−δ Mixed-Conducting Perovskites
PublikacjaOxides in which total electrical conductivity is determined by the partial conductivities of three types of charge carriers i.e. holes/ electrons, oxygen ions, and protons are key components of well-functioning proton ceramic fuel cells. Apart from electrochemical properties also easily modified microstructure is an important feature of the electrodes. In the paper, a group of SrTi1−xFexO3−δ (STF, x = 0.2–0.8) perovskites prepared...
-
Electrophoretic Deposition and Characteristics of Chitosan–Nanosilver Composite Coatings on a Nanotubular TiO2 Layer
PublikacjaThe surface treatment of titanium implants has been applied mainly to increase surface bioactivity and, more recently, to introduce antibacterial properties. To this end, composite coatings have been investigated, particularly those based on hydroxyapatite. The present research was aimed at the development of another coating type, chitosan–nanosilver, deposited on a Ti13Zr13Nb alloy. The research comprised characterization of the...
-
Fabrication of La-Doped Bi4Ti3O12 Ceramics
PublikacjaLa-modified Bi4Ti3O12 is a typical ferroelectric, piezoelectric and electro-optic material, having relatively low coercive field, low dielectric constant, high Curie temperature and high breakdown strength. Goal of the present research was to apply mixed oxide method for fabrication of BiTLax ceramics, study its chemical composition, crystalline structure and microstructure. The compound BiTLax for x=0, 0.25, 0.5, 0.75 ceramic...
-
Microstructural Design of Ba0.5La0.5Co0.5Fe0.5O3 Perovskite Ceramics
PublikacjaBa0.5La0.5Co0.5Fe0.5O3 was synthesized in the solid-state reaction route. The influence of ball milling parameters (such as milling media size, angular velocity, and time), pelletizing pressure, and annealing parameters on the microstructure was studied. The grain size distribution and density or specific surface area changes were investigated in each approach while the individual parameters were changed. The evaluation of BLCF...
-
THE POSSIBILITY OF USE OF LASER-MODIFIED Ti6Al4V ALLOY IN FRICTION PAIRS IN ENDOPROSTHESES
PublikacjaThe purpose of this paper is to show results of laser treatment at cryogenic conditions of the Ti6Al4V alloy used for orthopedic applications. That modification process ought to bring beneficial changes of microstructure and residual stresses in the surface layer. The paper presents the abrasive wear of the base and laser remelted material in association with ceramics Al2O3. Despite the surface cracking after laser treatment the...
-
Mechanical Properties and Wear Susceptibility Determined by Nanoindentation Technique of Ti13Nb13Zr Titanium Alloy after “Direct Laser Writing”
PublikacjaLaser treatment has often been applied to rebuild the surface layer of titanium and its alloys destined for long-term implants. Such treatment has always been associated with forming melted and re-solidified thin surface layers. The process parameters of such laser treatment can be different, including the patterning of a surface by so-called direct writing. In this research, pulse laser treatment was performed on the Ti13Nb13Zr...
-
The Effect of Welding Conditions on Mechanical Properties of Superduplex Stainless Steel Welded Joints
PublikacjaThe 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...
-
STRUKTURA SZKŁO-CERAMIKI ZAWIERAJĄCEJ FERROELEKTRYCZNĄ FAZĘ BiV
PublikacjaLiteratura opiusuje próby wytworzenia nanokompozytów, w których skład wchodzą matryca szkła i rozproszone w niej nanokrystality fazy ferroelektrycznej. Najczęstsza metoda wykorzystywana do otrzymywania takiej szkło - ceramiki polega na wytopie szkła, a następnie jego krystalizacji. W literaturze można znaleźć dużo przykładów wytwarzania tego typu materiałów dwu lub więcej składnikowych. Najwięcej badań dotyczy ferroelektrycznych...
-
Corrosion fatigue crack propagation rate characteristics for weldable ship and offshore steels with regard to the influence of loading frequency and seawater temperature
PublikacjaAfter Vosikovsky (1975), the corrosion fatigue crack growth rate (CFCGR) characteristics have been divided into three regions. The region-III rates are very close to mechanical fatigue crack growth rates. CFCGR formulae, including the long-crack length effect (in region I only), the loading frequency effect (in region II only), and the saltwater temperature effect, have been proposed. It has been assumed that CFCGR is proportional...
-
Cavitation Erosion of Nodular Cast Iron - Microstructural Effects
PublikacjaThe paper deals with susceptibility of nodular cast iron with ferritic-pearlitic matrix on cavitation erosion. Cavitation tests were carried out with the use of a cavitation erosion vibratory apparatus employing a vibration exciter operated at frequency of 20 kHz. The study allowed to determine the sequence of subsequent stages in which microstructure of cast iron in superficial regions is subject to degradation. The first features...
-
THE EFFECT OF WET UNDERWATER WELDING ON COLD CRACKING SUSCEPTIBILITY OF DUPLEX STAINLESS STEEL
PublikacjaABSTRACT The present work was conducted to assess the weldability of duplex stainless steel in underwater conditions. Metal manual arc welding (MMA) with the use of coated electrodes was used in the investigations. Tekken weldability tests were performed underwater at 0.5 m depth and in the air. Nondestructive tests, metallographic examinations of welds, ferrite content assessment in microstructure and hardness test were performed....
-
Effect of processing parameters on the cyclic behaviour of aluminium friction stir welded to spark plasma sintered aluminium matrix composites with bimodal micro-and nano-sized reinforcing alumina particles
PublikacjaUnderstanding the cyclic behaviour of Alumina reinforced Aluminium composites (Al-A2O3) was of critical importance, for their further application in the different industrial sectors. The present study is focussing on the cyclic behaviour of the Al-Alumina nanocomposite produced through the combination of spark plasma sintering (SPS) method and friction stir welding (FSW). The added Alumina with total content of 10% is the combination...
-
GTR/Thermoplastics Blends: How Do Interfacial Interactions Govern Processing and Physico-Mechanical Properties?
PublikacjaIn this work, GTR/thermoplastics blends (in ratio 50/50 and 75/25 wt.%) were prepared by melt-compounding in an internal mixer. During research, trans-polyoctenamer rubber (TOR), ethylene-vinyl acetate copolymer (EVA), ethylene-octene copolymer (EOC), and linear low-density polyethylene (LLDPE), were used in their thermoplastic phase. Microstructure and processing-performance property interrelationships of the studied materials...
-
Thermo-Mechanical Simulation of Underwater Friction Stir Welding of Low Carbon Steel
PublikacjaThis article investigates the flow of materials and weld formation during underwater friction stir welding (UFSW) of low carbon steel. A thermo-mechanical model is used to understand the relation between frictional heat phenomena during the welding and weld properties. To better understand the effects of the water environment, the simulation and experimental results were compared with the sample prepared by the traditional friction...
-
Structural Properties and Water Uptake of SrTi1−xFexO3−x/2−δ
PublikacjaIn this work, Fe-doped strontium titanate SrTi1−xFexO3−x/2−δ, for x = 0–1 (STFx), has been fabricated and studied. The structure and microstructure analysis showed that the Fe amount in SrTi1−xFexO3−x/2−δ has a great influence on the lattice parameter and microstructure, including the porosity and grain size. Oxygen nonstoichiometry studies performed by thermogravimetry at different atmospheres showed that the Fe-rich compositions...
-
Impedance Studies of Phosphate-iron Glasses Containing Niobium and Titanium
PublikacjaThe ac and dc conductivity in phosphate-iron-niobate glasses with addition of titanium oxide was investigated as a function of temperature and frequency with the use of impedance spectroscopy. The topography and microstructure of glasses were investigated by the means of X-ray diffraction (XRD), scanning electron microscopy (SEM), and confocal microscopy methods. The obtained results show that all samples are amorphous but they...
-
Termooksydacyjna i fotooksydacyjna degradacja pianek poliuretanowych
PublikacjaPrzeprowadzono ocenę efektywności działania wybranych środków przeciwstarzeniowych w sztywnych piankach poliuretanowych, otrzymywanych na drodze syntezy jednoetapowej. Ocenę tę oparto na pomia-rach zmian barwy oraz wytrzymałości mechanicznej zsyntezowanych materiałów. Na podstawie analizy uzyskanych wyników stwierdzono, iż dodatek 3% mieszaniny I rzędowego antyutleniacza fenolowego oraz benzotriazolowego absorbera UV znacząco zmniejsza...
-
Fabrication, structural and electrical properties of Sr(V,Nb)O 3-δ perovskite materials
PublikacjaThe SrV1-xNbxO3-δ materials with different niobium content in perovskite B-sublattice were prepared by a solid-state reaction process. The microstructure and phase compositions of obtained samples were analyzed by the X-ray diffraction technique (XRD) and scanning electron microscopy (SEM). The electrical conductivity of samples was measured by a DC 4-wire method in range of 100–600 °C in different gas conditions. The oxidation...
-
Influence of reduction process on the structural and mechanical properties of (Pb,Bi)-(Si,Ge)-O oxide glasses
PublikacjaThe effect of the reduction process in H2 at 380 °C on the microstructure and elemental composition of a glass Bi0.4Pb0.2Si0.4Ox has been investigated. It has been shown that after reduction a clearly separated top layer with a thickness of approx. 50 µm was formed on the surface of the sample. This layer is depleted of oxygen and has higher electrical conductivity than the interior of the glass. It has also been found that some...
-
Wpływ procesu redukcji na właściwości strukturalne i mechaniczne szkieł tlenkowych z grupy (Pb,Bi)-(Si,Ge)-O = Influence of reduction process on the structural and mechanical properties of (Pb,Bi)-(Si,Ge)-O oxide glasses
PublikacjaThe effect of the reduction process in H2 at 380 °C on the microstructure and elemental composition of a glass Bi0.4Pb0.2Si0.4Ox has been investigated. It has been shown that after reduction a clearly separated top layer with a thickness of approx. 50 µm was formed on the surface of the sample. This layer is depleted of oxygen and has higher electrical conductivity than the interior of the glass. It has also been found that some...
-
Determination of Failure Causes of a Steam Turbine Casing
PublikacjaThe paper presents results of research and failure analysis undertaken to determine failure causes of a steam turbine casing. After 130,000 hours of service the crack in a outer shell of the turbine casing was found. The inner shell of the casing was made of cast steel grade G21CrMoV5-7, and the outer shell of grade G20CrMo4-5. Following research were performed in order to determine causes of the casing failure: chemical analysis;...
-
Underwater Welding of Duplex Stainless Steel
PublikacjaThe present work was conducted to assess the weldability of duplex stainless steel at underwater conditions. Interest of underwater welding of this steel grade is connected with necessity of preparing welding repair technologies for subsea pipelines widely used in offshore oil and gas industry. The GMA local cavity welding method was used in the investigations. Welded beads were performed underwater at 0.5 m depth and in the air....
-
An adaptive approach to non-destructive evaluation (NDE) of cast irons containing precipitated graphite particles with the help of magnetoacoustic emission
PublikacjaPhysical properties of cast irons strongly depend on both their microstructure and the presence of casting defects. The paper analyses the possibility of application of magnetoacoustic emission (MAE) for nondestructive detection of flawed cast iron components. The investigated samples containing dross, chunky graphite and lamellar graphite were compared with the reference, flawless, spheroidal cast iron sample. The optimisation...
-
Kinetics of Intermetallic Phase Precipitation in Manual Metal Arc Welded Duplex Stainless Steels
PublikacjaThe article presents the influence of heat treatment on the kinetics of transformations in lean duplex LDX2101 steel and a weld made of standard duplex 2209 material, which was welded by manual metal arc welding. Changes in the microstructure, hardness, and magnetic phase content were analyzed after heat treatment was conducted at a temperature of 800 °C for a period ranging from 15 to 1440 min. Light and scanning microscopy, Vickers...
-
Effect of Processing Parameters on Strength and Corrosion Resistance of Friction Stir-Welded AA6082
PublikacjaThe friction stir welding method is increasingly attracting interest in the railway sector due to its environmental friendliness, low cost, and ease of producing high-quality joints. Using aluminum alloys reduces the weight of structures, increasing their payload and reducing fuel consumption and running costs. The following paper presents studies on the microstructure, strength, and corrosion resistance of AA6082 aluminum alloy...
-
N-doped carbon materials as electrodes for highly stable supercapacitors
PublikacjaThis article reports a strategy to use nitrogen-doped carbon materials as electrodes for supercapacitors. Depending on the carbon precursor, the porous structure is changed with specific surface area reached up to 2270 m2 g−1. The capacitance of carbon materials used as electrodes is related strictly to pore size. The microstructure and nitrogen functionalities enable a high capacitance (327 F g−1) and cycle durability. The nanoporous...
-
Influence of yttria surface modification on high temperature corrosion of porous Ni22Cr alloy
PublikacjaProtective coatings for porous alloys for high temperature use are relatively new materials. Their main drawback is high temperature corrosion. In this work protective coatings based the on Y-precursor infiltrated into the sintered Ni22Cr alloys are studied at 700°C. Effects of the amount of the protective phase on the resulting corrosion properties are evaluated in air and humidified hydrogen. Weight gain of the samples, their...
-
Investigation of changes in the type B PLC effect of Al–Mg–Cu type alloy for various strain rates
Publikacja -
Temperature distribution in laser-clad multi-layers
PublikacjaW pracy przedstawiono porownanie rezultatów numerycznej symulacji rozkładu temperatur w warstwach nakładanych laserowo z wynikami pomiarów doświadczalnych. Otrzymano bardzo dobrą zgodność wyników co pozwala wnioskować, że przedstawiony model numeryczny może służyć jako efektywne narzędzie wstępnego doboru parametrów procesu laserowego nakładania warstw.
-
Investigation of changes in the type B PLC effect of Al-Mg-Cu type alloy for various strain rates
PublikacjaEfekt Portevina-LeChateliera ujawnia się w postaci skokowych zmian naprężenia w trakcie procesu odkształcenia próbek pewnych stopów. Zjawisko PLC występuje w kilku odmianach charakteryzujących się istotnymi różnicami zarówno w przestrzennym rozkładzie pasm odkształcenia jak też przebiegu krzywej naprężeniowej. Przebiegi odpowiadające różnym odmianom serration charakteryzują się odmiennymi właściwościami rozkładu energetycznego...
-
Image-based numerical modeling of the tensile deformation behavior and mechanical properties of additive manufactured Ti–6Al–4V diamond lattice structures
PublikacjaThis work concerns the numerical modeling of the deformation process and mechanical properties of structures obtained by the additive method laser power bed fusion (LPBF). The investigation uses diamond structures of Ti–6Al–4V titanium implantation alloy with various relative densities. To model the process of tensile deformation of the materials, geometric models were used, mapping the realistic shape of the examined structures....
-
Evaluation of Praseodymium and Gadolinium Doped Ceria as a Possible Barrier Layer Material for Solid Oxide Cells
PublikacjaIn this work, nanocrystalline layers based on the Pr, Gd co-doped CeO2 were investigated. For the preparation of thin layers, lowtemperature spray pyrolysis technique was used. Different stoichiometries of the layers were produced for comparison on polished sapphire substrates. The microstructure of the prepared thin layers was studied by scanning electron microscopy (SEM), energydispersive X-ray spectroscopy (EDS) and X-ray diffractometry (XRD)....
-
Induction Assisted Hybrid Friction Stir Welding of Dissimilar Materials AA5052 Aluminium Alloy and X12Cr13 Stainless Steel
PublikacjaThis research aimed to study the induction in-situ heated hybrid friction stir welding (IAFSW) method to join AA5052 aluminium alloy with X12Cr13 stainless steel (SS) to enhance joint strength. The potency of this method on the mechanical properties and microstructural characterizations were also investigated. The results show that the transverse tensile strength gained was 94% of the AA5052 base metal that is 229.5 MPa. This superior...
-
Temperature Fiber-Optic Sensor with ZnO ALD Coating
PublikacjaThis study presents a microsphere-based fiber-optic sensor with a ZnO Atomic Layer Deposition (ALD) coating thickness of 100 nm for temperature measurements. Metrological properties of the sensor were investigated over the temperature range of 100 °C to 300 °C, with a 10 °C step. An interferometric signal is used to control whether the microstructure is whole. Spectrum shift of a reflected signal is used to ascertain changes in...
-
Influence of Heat Treatment Temperature on Fatigue Toughness in Medium-Carbon High-Strength Steels
PublikacjaCurrent research has demonstrated that the tempering temperature affects the martensitic transformation of medium-carbon high-strength steels. This temperature plays an important role in the final microstructure, percentage ratios of martensite to ferrite phases and, consequently, in the mechanical properties and the fatigue response. So far, the relationship between the martensitic tempering temperature and the cyclic deformation...
-
Cavitation Erosion Resistance Influence of Material Properties
PublikacjaThe 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,...
-
Corrosion degradation impact on mechanical properties of structural steel
PublikacjaRecently, extensive research was conducted regarding the impact of corrosion degradation on the mechanical properties of structural steel. Studies show that at the material level, the microstructure is somewhat unchanged due to corrosion degradation. However, the corrosion causes pits and structural surface irregularities that consequently impact the mean stress-strain response of typical coupon specimens subjected to tensile loading....
-
Analysis of features of stainless steels in dissimilar welded joints in chloride inducted corrosion
PublikacjaStainless steels of femtic-austenitic microstructure that means the duplex Cr-Ni-Mo steels, in comparison with austenitic steel includes less expensive nickel and has much better mechanical properties with good formability and corrosion resistance, even in environments containing chloride ions. Similar share of high chromium ferrite and austenite, which is characterized by high ductility, determines that the duplex steels have...
-
Investigation of Mechanical and Microstructural Properties of Welded Specimens of AA6061-T6 Alloy with Friction Stir Welding and Parallel Friction Stir Welding Methods
PublikacjaThe present study investigates the effect of two parameters of process type and tool offset on tensile, microhardness, and microstructure properties of AA6061-T6 aluminum alloy joints. Three methods of Friction Stir Welding (FSW), Advancing Parallel-Friction Stir Welding (AP-FSW), and Retreating Parallel-Friction Stir Welding (RP-FSW) were used. In addition, four modes of 0.5, 1, 1.5, and 2 mm of tool offset were used in two welding...
-
On the correlation between magnetoacoustic emission and magnetostriction dependence on the applied magnetic field
PublikacjaThe correlation between magnetoacoustic emission signal envelopes and magnetostriction curves is investigated. Two sets of samples are being considered: tempered martensitic steel and plastically deformed ferritic steel. It is shown that even though some general relations may be observed, as was demonstrated in the literature, the correlation is not always present. One may not expect to change both quantities in the same way if...
-
Multicomponent layers for aluminium alloys surface consolidation
PublikacjaThe main reason of the surface modification of the components such as pistons and cylinder blocks made of cast aluminium alloys is to obtain high hardness, wear and corrosion resistance of the working surface for larger lifetime of the motor-car and aircraft engines. In that aspect, the new conception of development - by hybrid method - of surface layers containing manganese, nitrogen, sulphur (Mn-N-S) and manganese, nitrogen,...
-
On the influence of a surface roughness on propagation of anti-plane short-length localized waves in a medium with surface coating
PublikacjaWe discuss the propagation of localized surface waves in the framework of the linear Gurtin–Murdoch surface elasticity and taking into account a roughness of a free boundary. We derive a boundary-value problem for anti-plane motions with curvilinear boundary and surface stresses. Using the asymptotic technique developed earlier, we obtain the form of a localized wave and analyze its amplitude evolution. As the main result we present...
-
Characterization of CaTi0.9Fe0.1O3/La0.98Mg0.02NbO4 composite
PublikacjaA composite of CaTi0.9Fe0.1O3 and electrolyte material, i.e. magnesium doped La0.98Mg0.02NbO4 was prepared and studied. The phase content and the sample microstructure was examined by an X-ray diffraction method and scanning electron microscopy. EDS measurements were done both for composite samples and the diffusion couple. The electrical properties were studied by four terminal DC method. The Ahigh-temperature interaction between...