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1

Analiza czynników mających wpływ na stateczność skarpy hałdy pokopalnianej

Łupieżowiec Marian, Kowalska Magdalena, Wróblewska Magdalena

Materiały Budowlane

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2024

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nr 2

73--78

2

Enhancement of Quinoa Grain Yield and Nutritional Quality by Potassium Fertilization Combined with Foliar Spraying of Seaweed Extract

Ali El-Sayed El-Shahat El-Sayed, El-Samad Emad El-Din Hassanein Abd, Abdelaal Hala Ahmed, AbouSekken Mahmoud Saad

Journal of Ecological Engineering

|

2023

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Vol. 24, nr 3

341--356

EN

The current work was carried out during the two growing seasons of 2016/2017 and 2017/2018 at the Experimental Station of the Environmental Studies and Research Institute, University of Sadat City, Sadat City, Menofia Governorate, Egypt. It aimed to investigate the effect of applying potassium fertilizer at 90, 140 and 190 kg K2O/ha combined with spraying applications of seaweed extract for four times in a 15-day interval starting at 40 days after sowing at rates of 0.0, 1.5 and 3.0 ml/L on the yield, mineral contents and nutritional quality of quinoa grains cv. CICA. A split-plot design was used in three replicates. Results reported that by increasing the application of potassium from 90 to 190 kg K2O/ha, gradual increases in all studied parameters of quinoa grains occurred in the seasons of 2016–2017 and 2017–2018, except for class B grain, Mg and fiber contents. Potassium application at 190 kg K2O/ha gave the highest significant values of all determined parameters in comparison with treatment of 90 kg K2O/ha. In most cases, insignificant differences were detected between potassium fertilizer levels of 140 and 190 kg K2O/ha. Spraying seaweed extract at 3.0 ml/L resulted in superiority of all studied characters except class B grain, Mg and fiber contents, followed by 1.5 ml/L treatment with insignificant differences between them in most cases. There were significant differences among spraying seaweed treatments on Ca, Fe, Mn, protein and fiber contents in both seasons, N, P and K during the first season, and grain yield/plant, total grain yield/ha and Zn content during the second season. The interaction between potassium fertilization levels and spraying applications of seaweed extract had significantly different effects on all studied characters during both seasons, except for Mg percentage. It is evident that the application of potassium fertilization at 140 or 190 kg K2O/ha combined with the spraying of seaweed extract at 3.0 ml/L caused an apparent enhancement of the yield, mineral contents and nutritional quality of quinoa grains during the two experimental seasons.

3

Grain size measurement using a semi-automatic calculation tool

Mernache Fatah, Sehisseh Abdelaziz, Amrane Amina, Hadji Said, Melhani Yasmine, Grine Mohamed, Messai Lakhdar

Computer Methods in Materials Science

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2023

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Vol. 23, No. 1

27--34

EN

This paper focuses on the development of a semi-automatic calculation tool to measure the Mean Linear Intercept (MLI) grain size of ceramics and other materials. The calculation tool was first verified and validated by using a certified micro-ruler and literature microstructures. It was then used to investigate the grain growth of UO2 pellets elaborated under different conditions. The tool offers the advantage of accuracy as well as the ability to quantify microstructures obtained with poor image quality. The estimated measurement errors were found to be less than 1 μm. The developed tool, mainly for the purpose of time-saving, allowed us to follow the microstructure (grain size) evolution of the elaborated UO2 fuel with different additives.

4

Accounting for the random character of nucleation in the modelling of phase transformations in steels

Poloczek Łukasz, Kuziak Roman, Foryś Jakub, Szeliga Danuta, Pietrzyk Maciej

Computer Methods in Materials Science

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2023

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Vol. 23, No. 2

17--28

EN

In our earlier work, a stochastic model of multi-stage deformation at elevated temperatures was developed. The model was applied to calculate histograms of dislocation density and grain size at the onset of phase transformation. The histograms were used as input data for the simulation of phase transitions using the traditional deterministic model. Following this approach, microstructural inhomogeneity was predicted for different cooling conditions. The results obtained, showing the effect of dislocation density and inhomogeneity of austenite grain size on the microstructural inhomogeneity of the final product, can be considered reliable as they are based on material models determined in previous publications and validated experimentally. The aim of the present work was to extend the model by taking into account the stochastic nature of nucleation during phase transitions. The analysis of existing stochastic models of nucleation was performed, and a model for ferritic transformation in steels was proposed. Simulations for constant cooling rates as well as for industrial cooling processes of steel rods were performed. In the latter case, uncertainties in defining the boundary conditions and segregation of elements were also considered. The reduction of the computing costs is an important advantage of the model, which is much faster when compared to full field models with explicit microstructure representation.

5

Electrochemical corrosion of aluminium alloy AA1050, processed by accumulative roll bonding

Ilieva M. D., Radev R. H.

Archives of Materials Science and Engineering

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2023

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Vol. 124, nr 1

5--13

EN

Purpose: To investigate the changes in corrosion behaviour of severely deformed by accumulative roll bonding aluminium alloy AA1050. Design/methodology/approach: To determine the influence of the accumulative roll bonding on microstructure, texture, and grain size, electron backscattered diffraction was used. Corrosion behaviour was evaluated in a 3.5 wt.% sodium chloride water solution using anodic polarisation. Findings: It was found out that accumulative roll bonding up to eight cycles led to an increase in corrosion rate compared to annealed alloy, but the increase in the number of cycles of accumulative roll bonding from two to eight shows a tendency toward lowering corrosion rates. It has a beneficial influence on pitting corrosion susceptibility. Research limitations/implications: The presented research focuses only on the influence of texture and grain size on severely deformed aluminium alloy AA1050 corrosion. Other factors, such as accumulated during deformation stresses, could also play their role in the corrosion process. Originality/value: The paper reports results on the influence of two factors – texture and grain size, on the corrosion of severely deformed aluminium alloy AA1050. Most reports on the topic include only the influence of texture or grain size.

6

Microstructure and mechanical properties of selective laser melted 18Ni300 steel

Liang Yan, Qing Luo, Yu He, Huili Zhao, Yuxin Wang

Materials Science Poland

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2022

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Vol. 40, No. 3

64--71

EN

The energy transfer process of selective laser melting (SLM) is highly complex. In this work, experiments were carried out to study the effects of SLM on the microstructure and mechanical properties of 18Ni300 martensitic steel. With the increase in laser power, the grain size of the cladding layer decreases and the microstructure becomes dense. The side hardness is higher than upper surface hardness, and the tensile strength and elongation both increase first and then decrease. When the laser power is 300 W and the scanning speed is 1,000 mm/s, the comprehensive mechanical properties are the best, as the tensile strength, microhardness, elongation at break, and elongation after fracture are 1,217 MPa, 37.5%, 37.6%, and 8.93%, respectively. EBSD (Electron Backscatter Diffraction) shows that columnar crystals grow along the growth direction (z direction) in XOZ and YOZ planes, and the grains show weak texture. There are many small-angle grain boundaries, and the grain sizes are <10 μm.

7

The analysis of the structure and the hardness of TIG-welded joints made of nickel superalloy Inconel 600

Górka Jacek, Kik Tomasz, Chruściel Marek, Jamrozik Wojciech, Kiel-Jamrozik Marta

Biuletyn Instytutu Spawalnictwa w Gliwicach

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2022

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Vol. 66, No. 4

37--44

EN

The tests discussed in the article aimed to analyse the structure and hardness of the heat affected zone and that of the weld in thin butt joints (1.0 mm) made of nickel superalloy Inconel 600 using the TIG method and variable welding linear energy restricted within the range of 45 J/mm to 80 J/mm. The test joints were subjected to visual tests, macro and microscopic metallographic tests, scanning electron microscopy-based structural observations and hardness measurements. The tests concerned with the effect of parameters applied during the TIG welding of butt joints made of 1.0 mm thick sheets (Inconel 600) in laboratory conditions revealed that the most favourable quality of the sheets was obtained when welding arc linear energy was restricted within the range of approximately 45 J/mm to 80 J/mm. An increase in linear energy within the above-presented range led to an increase in the width of the weld and that of the HAZ (observed in the joints subjected to macroscopic metallographic tests). In addition, an increase in linear energy restricted within the aforesaid range increased the grain size in matrix γ (in the HAZ) from approximately 120 μm to approximately 200 μm. The structure of the weld contained the zone of columnar grains oriented towards the fusion line as well as large groups of primary grains having the dendritic structure with clearly visible axes of primary dendrites of varied orientation. In addition, the weld structure also contained precipitates in the form of low-melting eutectics located in interdendritic spaces. The X-ray microanalysis concerning fragments having an area of 0.045mm2, examined in the individual zones of the welded joints made of Inconel 600, revealed only slight differences in terms of mass and atomic concentrations of the primary chemical elements of the superalloy matrix such as nickel, chromium and iron or larger differences as regards carbide-forming elements such as niobium and titanium and the concentration of carbon itself.

PL

Celem badań była analiza struktury i twardości strefy wpływu ciepła oraz spoiny w złączach doczołowych blach cienkich (1,0 mm) wykonanych z nadstopu niklu typu Inconel 600 metodą TIG, przy zmiennej energii linowej spawania w zakresie 45–80 J/mm. Uzyskane złącza spawane poddano: badaniom wizualnym, badaniom metalograficznym makro- i mikroskopowym, obserwacjom struktury w elektronowym mikroskopie skaningowym oraz pomiarowi twardości. Przeprowadzone badania wpływu parametrów procesu spawania metodą TIG złączy doczołowych ze stopu Inconel 600 o grubości 1 mm spawanych doczołowo wykazały, że: złącza blach cienkich z badanego nadstopu w warunkach laboratoryjnych wykazują najlepszą jakość przy zachowaniu energii liniowej łuku w zakresie ok. 45–80 J/mm, wzrost energii liniowej spawania w stosowanym zakresie powoduje zwiększenie szerokości spoiny i SWC badanych makroskopowo złączy, zwiększenie energii liniowej łuku w procesie w zakresie 45–80 J/mm powoduje w SWC wzrost wielkości ziaren osnowy γ odpowiednio od ok. 120 μm do ok. 200 μm, struktura spoiny wykazuje mniej lub bardziej wyraźną strefę ziaren słupkowych zorientowanych do linii wtopienia oraz duże kolonie ziaren pierwotnych o budowie dendrytycznej z wyraźnie ujawnionymi osiami głównymi dendrytów o różnej orientacji oraz wydzieleniami w postaci eutektyk niskotopliwych w przestrzeniach międzydendrytycznych, wyniki mikroanalizy rentgenowskiej z obszarów o powierzchni 0,045 mm2 badanych w poszczególnych strefach złącz blach spawanych z nadstopu Inconel 600 wykazują niewielkie zróżnicowanie wartości masowego i atomowego stężenia podstawowych pierwiastków osnowy nadstopu takich, jak nikiel, chrom i żelazo oraz większe w przypadku stężenia pierwiastków węglikotwórczych, takich jak niob i tytan, a także stężenia samego węgla.

8

A comparative Study on the Mechanical and Corrosion Properties of the ZM20 and ZM21 Alloys after Casting and Rolling

Gören Halil Ahmet, Ünal Mehmet, Türen Yunus, Ahlatçı Hayrettin, Sun Yavuz

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 4

1387--1394

EN

In this study, the effects of grain refinement and production methods on the corrosion, corrosive wear and mechanical properties of the as-cast and as-rolled Mg-2 wt.% Zn (ZM20) and Mg-2 wt.% Zn-0,51 wt.% Mn (ZM21) alloys were examined by using OM, XRD, SEM, hardness and uniaxial tensile test. Additionally, the potentiodynamic polarization, immersion corrosion test and corrosive wear properties of the ZM20 and ZM21 alloys were compared. According to the XRD results, MgZn and MgZn2 phases were found in the alloys and also MnZn3 phase occurred in the ZM21 alloy with the addition of manganese. Both during solidification forming nucleation points with the added manganese and during rolling the broken secondary phase particles distributed into the matrix prevented grain growth and led to the formation of a more refined structure. The tensile test results showed that the strength of the as-cast ZM21 alloys were better than that of the as-cast ZM20 alloys and further improvement in mechanical properties occurred with the rolling of the both alloys. The most superior hardness was found in the as-rolled ZM21 alloy. In the total 400-m reciprocal corrosive wear test in the 3.5% NaCl solution, the lowest mass loss was in the as-rolled ZM21 alloys. In the potentiodynamic corrosion test, the highest corrosion resistance was occurred by the as-cast ZM20 alloy.

9

A study of grain size effect on radon exhalation rate and uranium content of a phosphate rock

Jabbade Meryame, Nachab Abdellatif, Nourreddine Abdel Mjid, Errami Ezzoura, Benjelloun Mohammed

Acta Geophysica

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2022

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Vol. 70, no 6

2805--2812

EN

Assessment of the exhalation rate allows a classification of materials according to their potential risk of exposure to radon. The present study investigates the granulation effect on the radon exhalation rates from a phosphate sample. The phosphate sample was sieved into different grain size dimensions ranging from2 mm. The exhalation rate of each fraction was measured using the accumulation method. The radon exhalation rate was found to decrease with an increase in grain size above 0.125 mm. The influence of grain size on uranium content was also studied using the autoradiography method. The uranium concentration increased for the smallest grains (0.5 mm). The measured values of radon exhalation rates are under the limits reported worldwide.

10

Transformation of structure during friction stir welding

Vakulenko Igor Alex, Plitchenko Sergey, Kurt Bulent, Proydak Svetlana, Askerov Hangardas

Zeszyty Naukowe. Transport / Politechnika Śląska

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2021

|

z. 111

181--191

EN

In comparison with low carbon steels, there is increased interest in the use of aluminium-based alloys as materials for the manufacture of welded structures rolling stock of railway transport. During friction stir welding aluminium-based alloy, against the background of the analysis structural transformations, issues of development hardening processes are considered. Under conditions of existence, a temperature gradient at zone of weld formation, shown degree approximation alloy to the conditions of superplastic flow and influence from presence particles of the second phase on grain size of matrix is estimated. Evaluation of the separate influence grain size of matrix and state of solid solution at total hardness of the weld showed dependence of their contributions on temperature of hot plastic deformation. As the temperature of plastic deformation of alloy at area of the weld increases, contribution to the total hardness from grain size increase and on state of the solid solution decreases.

11

The qualitative-quantitative approach to microstructural characterization of nanostructured bainitic steels using electron microscopy methods

Królicka Aleksandra, Janik Aleksandra, Żak Andrzej, Radwański Krzysztof

Materials Science Poland

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2021

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Vol. 39, No. 2

188-199

EN

Both qualitative and quantitative analyses play a key role in the microstructural characterization of nanobainitic steels focused on their mechanical properties. This research demonstrates various methods of microstructure analysis using transmission electron microscopy (TEM), scanning electron microscopy (SEM), and electron backscatter diffraction (EBSD) techniques, taking into account these two approaches. The structural constituents have been qualitatively characterized using TEM and selected area electron diffraction (SAED), together with quantitative analysis based on the misorientation angle (EBSD). Besides, quantitative measurement of austenite with both blocky and film-like morphologies has been carried out. Due to the scale of nanostructured bainite, it is also important to control the thickness of bainitic ferrite and film-like austenite; hence, a method for measuring their thickness is presented. Finally, the possibility of measuring the prior-austenite grain size by the EBSD method is also demonstrated and compared with the conventional grain boundary etching method. The presented methods of qualitative and quantitative analyses form a complementary procedure for the microstructural characterization of nanoscale bainitic steels.

12

Reduction of Thermal Conductivity Through Complex Microstructure by Dispersion of Carbon Nanofiber in p-Type Bi0.5Sb1.5Te3 Alloys

Sharief P., Madavali B., Sohn Y., Han J. H., Song G., Hong S. J.

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

803--808

EN

The influence of nano dispersion on the thermoelectric properties of Bi2Te3 was actively investigating to wide-spread thermoelectric applications. Herein this report, we have systematically controlled the microstructure of Bi0.5Sb1.5Te3 (BST) alloys through the incorporation of carbon nanofiber (CNF), and studied their effect on thermoelectric properties, and mechanical properties. The BST/x-CNF (x-0, 0.05, 0.1, 0.2 wt.%) composites powder was fabricated using high energy ball milling, and subsequently consolidated the powder using spark plasma sintering. The identification of CNF in bulk composites was analyzed in Raman spectroscopy and corresponding CNF peaks were recognized. The BST matrix grain size was greatly reduced with CNF dispersion and consistently decreased along CNF percentage. The electrical conductivity was reduced and Seebeck coefficient varied in small-scale by embedding CNF. The thermal conductivity was progressively diminished, obtained lattice thermal conductivity was lowest compared to bare sample due to induced phonon scattering at interfaces of secondary phases as well as highly dense fine grain boundaries. The peak ZT of 0.95 achieved for 0.1 wt.% dispersed BST/CNF composites. The Vickers hardness value of 101.8 Hv was obtained for the BST/CNF composites.

13

Investigation the effect addition of nano Al2O3 on microstructure of Yttria tetragonal Zirconia polycrystalline ceramic

Alshaibani I.J.

Archives of Materials Science and Engineering

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2021

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Vol. 107, nr 2

49--55

EN

Purpose: This research aimed to prepare tetragonal zirconia polycrystals powder by coprecipitation method and study effects of addition of different amounts of nano Al2O3 (1, 2 and 4) wt.% on its microstructure and mechanical properties of (5Y-TZP) composite. Design/methodology/approach: The powder was uniaxial pressed at a pressure of 150 MPa and held for 60 s, and sintered at the 1500°C, held for two hours and then cooling down at 5°C/min to room temperature. Microhardness and fracture toughness tests were utilized to evaluate the mechanical properties of yttria tetragonal zirconia polycrystal composite. The microstructure has been observed using field emission scanning electron microscopy(FESEM). Findings: The results showed an addition of nano Al2O3 has a great influence on hardness and microstructure, the increase in Vicker's microhardness of composite samples with the increase in the nano Al2O3 wt.% and microstructure were characterized with homogeneous zirconia distribution, grain growth destruction with the increasing percentage of nano Al2O3. The most important influence is the enhancing of the densification process as the porosity decreased. The highest hardness and maximum fracture toughness were recorded at 4 wt.% nano Al2O3. Research limitations/implications: Ceramic matrix composites are developed to overcome the brittleness of ZrO2 and the low toughness of alumina by formation, a large difference of elastic behavior between matrix and particles(dispersion phase )which disturbs the stress field as a dislocation comes near a particle. Practical implications: Zirconia has mechanical properties similar to those of stainless steel. Yttria-stabilized tetragonal Zirconia (Y-TZP) is growing used in dentistry due to its good mechanical properties such as hardness and fracture toughness. Thus, controlling of microstructure by adding nanoalumina plays an important role in enhancing these properties. Originality/value: Study the adding bitty percentage from nano alumina on microstructure and mechanical properties of (5Y-TZP) ceramic.

14

Investigation on the Effect of Granulometric Features on the Permeability of No-Bake Resin Bonded Sand Cores

Hudák H., Gyarmati G., Varga L.

Archives of Foundry Engineering

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2021

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Vol. 21, iss. 2

99--105

EN

Foundry sand is the main element of sand mixtures from which molds or sand cores are made. Due to the continuous development of core making technologies, the selection of the right type of base sand becomes more and more important. The major features of foundry sand are determined by the following factors: chemical and mineralogical composition, sand grain size, grain size distribution, sand grain shape, and surface quality. The main goal of our research was to develop a qualification method that can be used to predict the characteristics of sand cores made from different sand types. Samples made from different types of foundry sand were used during the research whose properties were examined with a new qualification system, and then its connection with the gas permeability of sand cores was analyzed. Based on the research results, a strong correlation could be established between the suggested quality indicators: CQi (Core Quality Index), CG (Coefficient of Granulometry), and permeability.

15

Effects of Separated Fractions of FBC Bottom Ash on Selected Properties of Cement Mortars

Kledyński Zbigniew, Krysiak Łukasz

Civil and Environmental Engineering Reports

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2020

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Vol. 30, no. 4

1--20

EN

This paper discusses the effects of partial replacement of cement with fluidized bed bottom ash on the properties of mortars. The analyzed ash samples originating from four Polish power plants were separated by grain size selection into fine and coarse-grained fractions. This process leads to a creation of derivative samples of differing physical properties and, partially, phase compositions, as tested in XRD and TG analyses. Despite its high water demand, the obtained fine-grained fraction has the potential for application in cement based composites as a reactive, pozzolanic additive. An acceptable activity index may be reached when the sulfate content is limited, implying benefits of combining the ash with low gypsum cements. The coarse-grained fraction is significantly less reactive, while a high silica and aluminate content is related to improved mechanical properties of the composite. It can, therefore, potentially be used as a quasi-inert additive or a substitute for sand.

16

Effect of Zirconium on the Solidification Path and Structural Properties of Commercial AlSi10MgCu Alloys

Hajduch P., Djurdjevic M. B., Bolibruchová D., Simicevic Z.

Archives of Metallurgy and Materials

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2020

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Vol. 65, iss. 2

549--554

EN

Comprehensive understanding of the melt quality is of vital importance for foundry man. The effect of each particular element need to be properly analysed. Therefore, the aim of this paper was to analyse the impact of various content of zirconium on the solidification path and structural characteristics (SDAS, grain size, porosity) of as cast commercial AlSi10MgCu alloys. It has been found that addition of zirconium up to 0.24 wt.% reduce significantly the grains size (from 3.5 mm to 1.2 mm), SDAS (from 57.3 μm to 50.4 μm) and porosity (from 19% to 5%), leading to production of sound cast parts.

17

Effect of grain size on the physicomechanical properties

Ossia C. V., Big-Alabo A., Ekpruke E. O.

Advances in Manufacturing Science and Technology

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2020

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Vol. 44, nr 4

135--144

EN

In this study, locally available waste coconut (Cocos nucifera) shells (CSs) were investigated as possible replacement for asbestos-based brake pads. The CS-based brake pad was tested for its physicomechanical properties and compared with a commercial brake pad used as control sample. The results showed that (a) an improved interfacial bonding between the CS particles and the binder as the grain size decreases; (b) the 90 μm grain size sample had better physicomechanical properties than the control sample in all tests except the thermal conductivity and stability tests; and (c) the hardness, compressive strength, and density of the CS-based brake pad decreased with increasing grain size, whereas the absorption properties increased with increasing grain size. The study showed that further reduction of the grain size below 90 μm and matrix impregnation with metals of good thermal conductivity could provide significant improvements to properties of the CS-based brake pad.

18

Multi-scale numerical analysis of the effect of microstructural features on the mechanical behavior of polycrystalline Ti-6Al-4V alloy

Benmessaoud Fatna, Velay Vincent, Cheikh Mohammed, Vidal Vanessa, Boher Christine, Rézaï-Aria Farhad

Engineering Transactions

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2019

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Vol. 67, iss. 2

227--242

EN

The present work aims to model the influence of microstructural features of Ti-6Al-4V titanium alloy on its mechanical behavior. A multi-scale approach based on crystal plasticity is considered. The elasto-viscoplastic constitutive equations of Meric-Cailletaud are modified to take into consideration the effect of the grain size by introducing the Hall-Petch relationship at the local scale. This modified model is coupled with finite element calculations under small strain assumption to simulate the monotonic mechanical behavior of Ti-6A-4V at local and global scales. It is shown that the mechanical behavior of Ti-6Al-4V is drastically dependent upon the material features. Strong crystallographic texture can result in the formation of hardened and less hardened areas. Moreover, by increasing the grain size scattering, the heterogeneously deformed areas are multiplied. By decreasing the average grain size, the yield strength increases. It is observed that the effects of grain size, grain size scattering and crystallographic texture are coupled.

19

The influence of sintering technique on microstructure and properties of ZrO2/Al2O3 composite

Wojteczko Agnieszka, Wojteczko Kamil, Strzelecka Marta, Nam Tatyana, Jach Katarzyna, Rosiński Marcin, Bućko Mirosław M., Pędzich Zbigniew

Composites Theory and Practice

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2019

|

R. 19, nr 4

157--160

EN

The following paper presents the results of investigations on the microstructure and mechanical properties of sintered composites in the zirconia-alumina system, fabricated by various sintering techniques. The investigations were performed for a particulate composite consisting of two continuous ceramic phases - zirconia (TZP) and alumina (α-Al2O3), 50 vol.% each. Two different methods were used to produce the samples: pressureless sintering and the U-FAST technique. The microstructure of the obtained sintered composite samples was evaluated using a scanning electron microscope. In addition, the density of the sintered bodies, their hardness and fracture toughness were investigated to evaluate the mechanical properties. Based on the obtained results of the investigations, the influence of the sintering technique on the microstructure and mechanical properties of the sintered composites was determined.

PL

Niniejsza praca prezentuje wyniki badań mikrostruktury oraz właściwości mechanicznych spieków kompozytowych na bazie tlenku cyrkonu i tlenku glinu, otrzymanych różnymi technikami spiekania. Materiał wykorzystany do badań to kompozyt ziarnisty składający się z dwóch ciągłych faz ceramicznych - tlenku cyrkonu (TZP) i tlenku glinu (α-Al2O3), po 50% objętościowych każda. Próbki zostały wytworzone za pomocą dwóch różnych metod, tj. spiekania swobodnego oraz techniki U-FAST. Dokonano oceny mikrostruktury otrzymanych spieków kompozytowych za pomocą skaningowego mikroskopu elektronowego. Dodatkowo przeprowadzono badanie ich stopnia zagęszczenia oraz ich twardości i odporności na kruche pękanie w celu określenia właściwości mechanicznych. Na podstawie otrzymanych wyników określono wpływ techniki spiekania na mikrostrukturę spieków kompozytowych, a co za tym idzie na ich właściwości mechaniczne.

20

Analiza właściwości materiałów filtracyjnych z dodatkiem nanowłókien

Dziubak Tadeusz, Yendzheiovskyi Yurii

Biuletyn Wojskowej Akademii Technicznej

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2019

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Vol. 68, nr 1

111--129

PL

Przedstawiono właściwości nanowłókien, metody ich wytwarzania oraz obszary zastosowania. Zaprezentowano oraz przeanalizowano parametry charakteryzujące materiały filtracyjne z dodatkiem nanowłókien. Opracowano metodykę badań charakterystyki aerodynamicznej oraz charakterystyki: skuteczności, dokładności i oporu przepływu wkładów filtracyjnych z dodatkiem nanowłókien w zależności od współczynnika chłonności pyłu km. Przedstawiono charakterystyczne parametry filtracyjne materiałów z dodatkiem nanowłókien. Wykonano pięć wkładów różniących się materiałem filtracyjnym z dodatkiem nanowłókien oraz bez tej warstwy. Opracowano warunki badań oraz przygotowano stanowisko badawcze. Przeprowadzono badania charakterystyk aerodynamicznych wykonanych wkładów filtracyjnych oraz charakterystyk skuteczności i dokładności filtracji i oporów przepływu wkładu standardowego (celulozowego), a także z dodatkiem nanowłókien. Potwierdzono pozytywny wpływ warstwy nanowłókien na wzrost skuteczności i dokładności filtracji powietrza wlotowego do silnika. Dokonano oceny składu granulometrycznego pyłu w powietrzu za standardowym wkładem filtracyjnym i wkładem z dodatkiem nanowłókien.

EN

Nanofiber properties, methods of their production, and areas of their application have been presented. Parameters describing filtration materials with nanofibers addition were presented, and analyzed. Methodology for testing aerodynamic characteristics as well as characteristics of: efficiency, accuracy, and filter cartridges resistance with nanofibers addition, depending on the dust mass loading km were developed. Characteristic filtration parameters of the materials with nanofibers addition are presented. Five filtration inserts, differing in the filtration material with nanofibers addition, and without this layer were made. Test conditions were developed as well as a test stand was prepared. Aerodynamic characteristics tests of filter cartridges as well as filtration efficiency, accuracy, and flow resistance of standard (cellulose) cartridge, and the ones with nanofibers addition were performed. The positive effect of nanofiber layer on efficiency, and accuracy increase in the inlet engine air filtration was confirmed. Granulometric composition of air dust was assessed on a standard filter cartridge, and on a cartridge with nanofibers addition.