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1

Badania zmian w strukturze płyt włóknisto-cementowych poddanych oddziaływaniom wybranych czynników eksploatacyjnych

Gorzelańczyk Tomasz

Przegląd Budowlany

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2024

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R. 95, nr 3

110--115

PL

W artykule przedstawiono wyniki badań wpływu zamrażania-rozmrażania oraz naświetlania promieniowaniem UV w komorze starzeniowej na strukturę płyt włóknisto-cementowych. W celu wykazania wpływu wyżej wymienionych czynników płyty w pierwszej kolejności przebadano z wykorzystaniem metody emisji akustycznej w próbie trójpunktowego zginania. Badania te wykazały wyraźny spadek liczby zarejestrowanych zdarzeń EA dla badanych płyt, szczególnie dla tych, które były poddane oddziaływaniu cykli zamrażania-rozmrażania w porównaniu z płytami referencyjnymi. Następnie w celu dokładniejszego zobrazowania zmian zachodzących w strukturze badanych płyt przeprowadzono badania z wykorzystaniem elektronowego mikroskopu skaningowego SEM.

EN

The article presents the results of research on the effect of cyclic freeze-thaw and UV irradiation on the structure of fibre-cement boards in an aging chamber. In order to demonstrate the impact of the above-mentioned factors, the panels were first tested using the acoustic emission method in the three-point bending test. These studies showed a clear decrease in the number of recorded EA events for the tested boards, especially for those that were subjected to freeze-thaw cycles compared to the reference boards. Then, in order to more accurately illustrate the changes occurring in the structure of the tested boards, tests were carried out using a scanning electron microscope (SEM).

2

Two-body wear simulation influence on some direct and indirect dental resin biocomposites : A qualitative analysis

Caracostea A., Morar N., Florea A., Soanca A., Badea M. E.

Acta of Bioengineering and Biomechanics

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2016

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Vol. 18, no. 3

61--72

EN

Purpose: The aim of this study was to qualitatively assess the outcomes of two in vitro aging methods, thermal-cycling and twobody wear simulation accomplished with a dual-axis chewing device, on the surface characteristics of eight direct and indirect dental resin biocomposites. Methods: Eighty mesial-occlusal-distal dental cavities were restored with four direct nanohybrid composite materials and with four nano- and micro-hybrid lab-fabricated resin composite inlays. After the restored teeth were subjected to thermal-cycling and wear simulation based on mechanical loading, the surface texture features of the restorations were separately analysed for each of the methods, on epoxy resin models using a digital camera, computer-aided-design system, optical stereo-microscopy and scanning electron microscopy. Results: All the dental restorative resin based composites used in this investigation displayed different cyclic wear patterns after undergoing mechanical loading. After thermal-cycling, the group of resin composite inlays showed a better adaptation, a smoother and more polished occlusal surface compared with direct restorative materials. Only two of direct nanohybrid resin composites performed better after two aging methods. One nanohybrid and the other two microhybrid resin inlays did not perform as expected when they were subjected to simulated wear compared to the rest of test materials. Conclusions: The use of the two-body wear simulation method revealed important information about the behavior of the dental resin-based composites when multiple oral factors are involved in a lab-simulated condition. Furthermore, the macro- and micro-morphological analysis showed different abrasion patterns among the materials being tested according to the filler percentage and distribution of the particles within the resin matrix.

3

Failure analysis (experimental and numerical approach) of gas turbine generator cooling fan in comparison between using 2types (14◦ and 19◦ angle of attack) of blades

Jahangiri A., Torshizi S. E. M., Nikravesh S. M. Y.

Engineering Transactions

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2013

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Vol. 61, iss. 2

99--117

EN

In gas turbine power plants, a fan is used as a cooling system to dissipate generated heat in coils (copper conductors) and generator electric circuits at the end sides of its rotor. In some cases, fracture of blades causes a short circuit between rotor and stator and consequently generator explosion and ﬁnancial problems. The fracture of cooling fan blades has occurred ﬁve times at the turbine side of the generator in our case of study, just 100hr after resuming operations after an overhaul. Using numerical analysis as well as laboratory investigation – including visual inspections, metallography and SEM – can help better ﬁnd failure problems that cause blade failures. A series of numerical analysis was performed to diagnose the possible cause of failure. CFD analysis is used to study the airﬂow distribution in order to observe probable separation phenomenon and pressure forces as they are imposed on fan blades due to operation. A ﬁnite element method was utilized to determine the stresses and dynamic characteristics of the fan blade (natural frequencies, stresses and vibrations).

4

Effect of high power diode laser surface melting and cooling rate on microstructure and properties of magnesium alloys

Dobrzański L. A., Tański T., Domagała J., Malara S., Król M.

Journal of Achievements in Materials and Manufacturing Engineering

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2009

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Vol. 37, nr 2

238-257

EN

Purpose: The goal of this paper is to present the investigation results of MCMgAl12Zn1, MCMgAl9Zn1, MCMgAl6Zn1, MCMgAl3Zn1 cast magnesium alloy in as-cast state and after heat treatment, as well as after laser treatment and thermal analysis during melting and solidification cycles carried out using the Universal Metallurgical Simulator and Analyser. In the following paper the structure and properties were presented of the above mentioned magnesium cast alloys in as-cast state and after a heat treatment. Design/methodology/approach: A casting cycle of alloys was carried out in an induction crucible furnace using a protective salt bath Flux 12 was equipped with two ceramic filters at the melting temperature of 750š10°C, suitable for manufactured material. The following results concern scanning electron microscopy investigations in the SE observation mode, as well as using BSE modus for better phase contrast results, also quantitative microanalysis was applied for chemical composition investigations of the phases occurred. Findings: The analysis of the samples after the ageing process has confirmed that the microstructure of the magnesium cast alloy consists of the solid solution a - Mg (matrix) of the secondary phase b - Mg17Al12 equally located in the structure. The roughness of the surface treatment layer was varied with laser power and also scan rate. Research limitations/implications: According to the alloys characteristics, the applied cooling rate and alloy additions seem to be a good compromise for mechanical properties and microstructures, nevertheless, further tests should be carried out in order to examine different cooling rates and parameters of solution treatment process and ageing process. Practical implications: A desire to create as light vehicle construction as possible and connected low fuel consumption made it possible to make use of magnesium alloys as constructional material in automotive industry. Originality/value: The undertaken examinations aim at defining the influence of chemical composition and precipitation processes on the structure and casting magnesium alloy properties in its state and after heat treatment with a different content of alloy components.

5

The influence of long-term annealing on the microstructure of Elektron 21 magnesium alloy

Kiełbus A.

Inżynieria Materiałowa

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2008

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Vol. 29, nr 4

310-315

EN

Elektron 21 is a new magnesium based casting alloy for used to 200°C. The microstructural changes after long-term annealing at 520°C (2-48 h) and 350°C (500-5000 h) have been presented. For the microstructure observation, a OLYMPUS GX71 metallographic microscope and a HITACHI S-3400N scanning electron microscope were used. Quantitative examination was conducted using the Met-Ilo automatic image analysis program. The Elektron 21 alloy in as-cast condition is characterized by a solid solution structure a with precipitates of Mg12(Nd,Gd) intermetallic phase on grain boundaries. After annealing (solutioning) at 520°C a reduction of the number of Mgi2(Nd,Gd) phase precipitates was observed. Its area fraction falls with the extension of the treatment time from AA=6.55% (as cast state) to AA= 0.5% (24 h of treatment). Also, an increase of the solid solution a grain size was observed from A=649 um2 to J=3000 um2. After annealing at 350°C the precipitation of Mg41Nd5 phase was observed. Its area fraction falls with the extension of the treatment time from AA=3.55% (500 h) to AA=5.55 % (5000 h of treatment). The solid solution a grain size didn't change.

PL

Stop magnezu Elektron 21 jest nowym stopem przeznaczonym do pracy w temperaturze do 200°C. W artykule zaprezentowano zmiany mikrostruktury podczas długotrwałego wyżarzania w temperaturze 500°C (2-48 h) i 350°C (500-5000 h). Do badań mikrostruktury zastosowano mikroskop optyczny OLYMPUS GX71 oraz mikroskop elektronowy skaningowy HITACHI S-3400N. Ilościową ocenę mikrostruktury przeprowadzono z wykorzystaniem programu "Met-Ilo". Stop Elektron 21 w stanie lanym charakteryzuje się strukturą roztworu stałego z wydzieleniami fazy Mg12(Nd,Gd) na granicach ziaren. Po wyżarzaniu (przesycaniu) w temperaturze 520°C obserwowano zmniejszenie udziału objętościowego fazy Mg12(Nd,Gd) z poziomu AA=6,55% (stan lany) do poziomu AA=0,5% (po 24 h obróbki). Natomiast średnie pole powierzchni płaskiego przekroju ziarna roztworu stałego zwiększało się z A=649 um2 do A=3000 um2. Po wyżarzaniu w temperaturze 350°C obserwowano wydzielanie fazy Mg41Nd5. Jej udział objętościowy zwiększa się wraz z wydłużaniem czasu obróbki z AA=3,55% (po 500 h) do AA=5,55% (po 5000 h). Średnie pole powierzchni płaskiego przekroju ziarna roztworu stałego nie zmienia się.

6

Processing and characterisation of particulate reinforced aluminium silicon matrix composite

Hamouda A. M. S., Sulaiman S., Vijayaram T. R., Sayuti M., Ahmad M. H. M.

Journal of Achievements in Materials and Manufacturing Engineering

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2007

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Vol. 25, nr 2

11-16

EN

Purpose: This paper describes and discusses the processing and characterization of quartz particulate reinforced aluminium-silicon alloy matrix composite. Design/methodology/approach: In this regard, quartz-silicon dioxide particulate reinforced LM6 alloy matrix composites were fabricated by carbon dioxide sand molding process with different particulate volume fraction. Tensile tests and scanning electron microscopic studies were conducted to determine the maximum load, tensile strength, modulus of elasticity and fracture surface analysis have been performed to characterize the morphological aspects of the test samples after tensile testing. Findings: Hardness values are measured for the quartz particulate reinforced LM6 alloy composites and it has been found that it gradually increases with increased addition of the reinforcement phase. The tensile strength of the composites decreases with the increase in addition of quartz particulate. Research limitations/implications: The results allows to determine the structure and properties of the aluminium silicon matrix composite materials. Originality /value: In addition, this research article is well featured by the particulate-matrix bonding and interface studies which have been conducted to understand the processed composite materials mechanical behavior and it was well supported by the fractographs taken using the scanning electron microscope (SEM).

7

TEM study of the precipitation process in HSLA-100 copper bearing steel

Lis A. K., Wieczorek P.

Inżynieria Materiałowa

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2004

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R. XXV, nr 3

166-168

EN

HSLA-100 steels contain increased addition of alloying elements such as Cr, Mn, Mo, Cu and Ni. They are also microalloyed with Nb and Ti, and sometimes additionally with aluminium and boron. Precipitation of carbides, carbonitrides in steels is complex in nature due to several elements with high affinity to carbon and nitrogen. This phenomenon plays a significant role in the microstructure evolution of these steels during thermomechanical processing. The precipitates formed at 853 K during ageing time from 1 to 100 hours of HSLA-100 steel containing 0.03% C, 0.60% Cr, 0.93% Mn, 0.6% Mo, 0.039% Nb, 3.44% Ni, 0.5% Cu were studied using transmission electron microscope. The selected area diffraction and EDS techniques were used to identify the precipitates. The investigations showed that several types of precipitates were present in the steel. The type of precipitates and their morphology are discussed.

PL

Badano przebieg procesu wydzieleniowego w stali z grupy HSLA, o składzie chemicznym podanym w Tabeli 1. Badaniom poddano próbki po hartowaniu z temperatury 1173 K i starzeniu w 853 k w czasie od 1 do 100 godzin. Po procesie hartowania otrzymywano strukturę bainityczno-martenzytyczną przedstawioną na rys. 1. W trakcie przebiegu procesu starzenia zaobserwowano dla krótkich czasów starzenia wydzielanie się fazy węglikowej typu M2C (rys. 2). Wydłużenie czasu starzenia skutkowało intensyfikacją wydzielania się fazy epsilon_Cu (rys. 3 i 4). Dokonano oceny parametrów stereologicznych wydzieleń, które przedstawiono w tabeli 2. Badania strukturalne przeprowadzono z wykorzystaniem transmisyjnego oraz skaningowego mikroskopu elektronowego.

8

Structural and morphological changes in copper hydroxocarbonate-1 aluminium system induced by mechanical activation

Wieczorek-Ciurowa K., Gamrat K., Fela K., Sawłowicz Z.

Polish Journal of Chemical Technology

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2003

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Vol. 5, nr 3

72-74

EN

The copper hydroxocarbonate with Al mixture was mechanically activated (MA) using a planetary ball mill and the products were examined by scanning electron microscopy (SEM) with energy dispersive X-ray microanalysis (EDX). Backscattered electron (BSE) imaging was used to localize the alloy phases formed as a result of mechanochemical reactions. These information were compared with thermal analysis and powder X-ray diffraction studies.

9

Backscattered electrons topographic mode problems in the scanning electron microscope.

Kaczmarek D.

Optica Applicata

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2001

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Vol. 31, nr 3

649-658

EN

The application of several backscattered electron (BSE) detectors makes it possible to separate topographic (TOPO) contrasts and material (COMPO) contrasts in a 'scanning' electron microscope (SEM). The BSE signals from six p-i-n diodes were used to investigate some artifacts connected with the reconstruction of real topography. The location of these diodes had been predicted theoretically to obtain algebraic formulas for the appropriate mixing of the BSE signal from the detectors. The specimen surface was specially prepared for estimation of the surface reconstruction quality. The TOPO mode in the SEM was realized with the use of analog and digital methods. The experimental and theoretical analysis indicates that the signal difference from the detector placed at higher angles (in relation to x axis) is preferable for topography reconstruction. The goal-of this paper is to discuss some ways of eliminating the artifact that-the structures parallel to the connection lines of diametral detectors can only be imaged with less contrast.

10

Ratujemy zabytkowe rękopisy, czyli badania procesów degradacji celulozy w laboratorium chemicznym

Bulska E., Wagner B.

Analityka : nauka i praktyka

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2000

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nr 1

4--6

11

The structure of the Cu-SiC composite interface.

Olszówka-Myalska A., Braszczyńska K.N.

Inżynieria Materiałowa

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1998

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R. XIX, nr 4

739-744

12

Ridging phenomenon in ferritic stainless steels.

Sztwiertnia K., Pospiech J., Bethke K.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

264-267

EN

FeCr17 ferritic stainless steel sheets, after cold rolling and annealing, exhibits ridging in the case of rolling direction elongation. The resulting deterioration in surface quality is a serve and long known problem in industrial processing. This problem is here investigated by the SEM-EBSD technique (Electron Backscattering Diffraction in the Scanning Electron Microscope). The results of the single orientation analysis suggest that to clarify the origin of the ridging morphology ealier models such as that elaborated by Wright (4) can be adopted.

13

Microtexture and microstructure investigations by orientation imaging microscopy.

Bunsch A., Jensen D.J., Hansen N.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

455-458

EN

The OIM technique is presented and examples of OIMs from recrystallized and cold deformed aluminium are given. It was found that the grain structures of the recrystallized samples are well resolved by the OIMs. Grain subdivision on different length scales during deformation is also clearly visible. The development in orientational grain subdivision is followed as a function of strain up to Epsilon=0.8 and the results are presented both by OIM pictures, average misorientations and misorientation distributions. Finally the potentials of the OIM technique are discussed.

14

Methods of M-A islands etching for quantitive analysis of HSLA steels.

Ziewiec A., Kędzierski Z.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

291-294

EN

Investigations of (martensite - austenite) M-A islands in HSLA X65 and X70 steels grade have been carried out. Since the traditional 'Nital' and 'Picral' etchants were inadequate for revealing M-A islands in a suitable way, a special technique of etching was prepared to obtain the effect of more selective etching for metallographic and scanning microscope studies. Metallograpgic investigations included revealing and evaluation of volume fraction of M-A islands as function of cooling time. TEM studies were performed to confirm the optical microscope observations.

15

Metallurgical applications of electron back-scattering patterns.

Hutchinson B., Ryde L., Lindh E.

Inżynieria Materiałowa

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1998

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R. XIX, nr 3

124-129

EN

One of the most interesting developments in the area of quantitive metallography has been the possibility of obtaining diffraction patterns (electron back-scattering patterns or EBSPs) in the scanning electron microscope. The presentation gives a short description of the EBSP method and also the way in which it can be combined with automatic movement of the electron beam position to create an orientation imaging micrograph (OIM). Examples are then given of various applications of the EBSP/OIM method to practical problems relating to industrial metallic materials.