Browsing by Subject "microstructure"

Now showing 1 - 20 of 28

Access status: Open Access ,
3D Microstructure Reconstruction of Tetragonal Zirconia Polycrystalline
(AGH University Press, 2025) Grabowski, Grzegorz
The microstructure of a material is fundamental to its properties and behavior under mechanical and thermal loads. Understanding the internal structure of a material and controlling the microstructure at the stage of ceramic materials synthesis are essential for designing materials with desired properties. This study focuses on the three-dimensional reconstruction of the microstructure of yttria-stabilized tetragonal zirconia polycrystalline (TZP). The goal was to create accurate digital models of the microstructure which could be used for further material analysis. The study utilized images obtained through scanning electron microscopy (SEM), on the basis of which the fundamental stereological parameters were determined. The microstructure reconstruction was performed using the Laguerre tessellation method, allowing for the generation of three-dimensional digital models of the microstructure that represent the material’s internal structure. The results confirm that, based on the basic stereological parameters obtained from two-dimensional cross-sections, three-dimensional reconstruction of the microstructure of polycrystalline zirconia is possible. This work, therefore, represents a step towards the effective design of ceramic materials with high performance parameters, through the control and optimization of their microstructure.
Access status: Open Access ,
A Characterization of the Impact Toughness of Hot-rolled HSLA Steel
(AGH University Press, 2024) Hamryszczak, Tomasz; Śleboda, Tomasz; Lypchanskyi, Oleksandr; Pańcikiewicz, Krzysztof
Due to the wide use of HSLA steels in difficult conditions, e.g. at low temperatures, it is extremely important to test the impact strength of these steels. This is equally important because most of those structures are made by welding these steels, and the welding process itself has a significant impact on the properties of joints and welding zones. In this work, the authors analyzed two selected representative HSLA steels rolled in the Krakow branch of ArcelorMittal Poland S.A. – the only place in Poland where HSLA steels in the form of hot-rolled strips can be produced on an industrial scale. Impact tests were performed in accordance with technical acceptance standards, and then the fracture surfaces after impact tests were characterized using light and scanning microscopy. In the next part of the work, a set of previously gathered data were analyzed to determine the influence of thermomechanical rolling process parameters on the level of impact strength and the influence of chemical composition on it.
Access status: Open Access ,
A simulation and experimental investigation of the thermal characteristics of refractory bricks produced using fireclay and agroforestry wastes
(AGH University Press, 2022) Obidiegwu, Eugenia Obiageli; Esezobor, David Ehigie; Mgbemere, Henry Ekene; Chiosa Odili, Cletus
Manufacturing and processing industries usually consume large quantities of materials and energy in the course of their operations. The energy supplied for high-temperature processes are used partially for the actual technical process and between 30 to 40% of the energy escapes through the walls of the reactor into the atmosphere, leading to a high degree of thermal inefficiency and fuel consumption. This paper studies the thermal behaviour of insulating refractory bricks produced from a blend of fireclay and agroforestry wastes. The fireclays used were obtained from Ukpor deposit in Anambra State (Latitude 5.95°N, Longitude 6.92°E), Osiele deposit in Abeokuta, Ogun State (Latitude 7.18°N, Longitude 3.45°E) and Kankara Katsina State (Latitude 11.93°N, Longitude 7.41°E), all of which are in Nigeria. Samples were prepared with various weight percentages (60-100 wt.%) clays and (0-40 wt.%) of agroforestry waste, with grain sizes between 212 and 600 µm. Raw materials and the developed refractory bricks were characterised using appropriate standard techniques. The chemical, mineralogical constituents and phases present in the microstructure were examined. Physical and thermo-mechanical properties were investigated. The insulating refractory bricks developed have porosity of 78.83% , cold crushing strength (CCS) 3.144 kN/m$^{2}$ and thermal conductivity 0.04-0.046 W/(m$\cdot$K) that compare favourably with imported bricks 75-85%, 2.756 kN/m$^{2}$ and 0.049 W/(m$\cdot$K) in both physical, mechanical and thermal properties respectively. The reason is that the agroforestry waste used (coconut shell), served to create the pores that improve insulation after burning. Also the ash that remains serves as reinforcement to improve the mechanical properties. The thermal behaviour of the bricks was studied using Finite Element Method and shows a strong correlation with the experimental findings. This indicates that the produced insulating bricks have the thermal properties required for insulation of furnaces.
Access status: Open Access ,
AA2024/fly ash lightweight composites fabricated by powder metallurgy
(2024) Nikiel, Piotr
The paper presents the experimental results on the fabrication of lightweight aluminum alloy AA2024 matrix composites reinforced with fly ash microspheres using powder metallurgy (PM) via hot pressing. The primary aim was to achieve a composite with the highest possible matrix density while preserving undamaged microspheres. A mixture of powders consisting of AA2024 alloy powder and 10 wt% fly ash was pressed at 550°C and pressures of 5, 10, 20, and 30 MPa for two minutes. The obtained composites had densities in the range of 1.93 - 2.31 g/cm3. Microstructural analysis revealed uniform distribution of the fly ash microspheres in the aluminum alloy matrix. The hardness of the composites was comparable only between the samples pressed at 10, 20, and 30 MPa, falling within the range of 118 to 122 HV0.1. The sample pressed at 5 MPa exhibited significantly lower hardness of 98.8 HV0.1. The composites produced by pressing at 20 and 30 MPa were characterized by high yield strength and compression strength, ranging from 211 to 216 MPa and 300 to 354 MPa, respectively. The composites pressed applying lower pressures, especially those at 5 MPa, exhibited significantly lower values of plastic yield strength and compression strength, with values of 109 MPa and 115 MPa, respectively. Taking into account the density, the number of damaged microspheres, and the microstructure of the AA2024/fly ash composite, the optimal pressing range is between 10 - 20 MPa, but superior mechanical properties were achieved after pressing at 20 and 30 MPa.
Access status: Open Access ,
An efficient Monte Carlo Potts method for the grain growth simulation of single-phase systems
(2020) Maazi, Noureddine; Lezzar, Balahouane
The choice of the lattice sites to be reoriented in the Monte Carlo Potts algorithm for grain growth simulation is repeated in a non-homogeneous way. Therefore, some grains are favorably growing than others. This fact may seriously affect the simulationresults. Soa modified MC method is presented. Lattice sites are selected for reorientation one by one following their positions in the matrix in each Monte Carlo step (mcs). This approach ensures that the various selections of one lattice site within every mcs are eliminated, and no favorable growth of grains at the expense of others. The calculation time considerably decreases. The effect of real-time and physical temperature on the grain growth kinetics is discussed.
Access status: Open Access ,
Analiza anizotropii właściwości mechanicznych stopu magnezu typu WE43
(Wydawnictwa AGH, 2023) Dudziński, Michał; Waląg, Michał; Kula, Anna
The article presents experimental work on the anisotropy aspects of the mechanical properties of WE43 alloy and technically pure magnesium (99.95%) obtained by hot extrusion. The experimental work includes structural and phase characterisation of as-extruded materials and uniaxial compression tests conducted parallel and perpendicular to the extrusion direction. Complementary studies of the macrotexture of materials before and after plastic deformation were carried out. Based on received results the degree of anisotropy of the mechanical properties of the tested materials was determined. The texture was identified as an important factor determining the activation of particular deformation mode of the materials after extrusion. Keywords: WE43 alloy, anisotropy, texture, compression test, microstructure
Access status: Restricted ,
Badanie właściwości sprężystych nanokompozytów polioksymetylenowych zawierających modyfikowany hydroksyapatyt
(Data obrony: 2018-01-29) Łaś, Michał
Wydział Elektrotechniki, Automatyki, Informatyki i Inżynierii Biomedycznej
Access status: Open Access ,
Characteristics of Al-Fe sinters made by the powder metallurgy route
(Wydawnictwa AGH, 2018) Majchrowska, Magdalena; Pałka, Paweł; Sułkowski, Bartosz; Lasek, Konrad; Nowak, Maja
The Al/Fe material was prepared by the powder metallurgy route with an additional intermediate stage which was a centrifuge of powder mixture. The application of the centrifuge stage was applied to obtain circular phase distribution of Al-rich phases in a sintered material. Iron powder with a particle size under 100 ?m and aluminum powder with a particle size of about 25 ?m, were used as starting materials. To determine the effect of centrifuging time on the distribution of Fe-Al particles, scanning electron microscopy (SEM, EDS) and XRD techniques were used. Microstructure observations show the influence of the centrifuging time on the distribution of Fe particles. It was observed that a longer centrifuging time caused changes in the ratio concentration of elements and allowed the growth of the intermetallic phase at the interface between solid Al and Fe particles.
Access status: Open Access ,
Characterization of microstructure and mechanical properties of laser-welded stainless steels
(Wydawnictwa AGH, 2016) Koclęga, Damian; Radziszewska, Agnieszka; Kąc, Sławomir; Zowczak, Włodzimierz; Dębowska, Aleksandra; Jędrusik, Mateusz; Petrzak, Paweł
This work presents the laser welding of dissimilar X12CrCoWVNbN12-2-2 and X10CrNi18-10 steels. This system is of interest, as laser welding offers new flexibility in the joining of metals and laser welds (LWs) and are usually of high quality, they are obtained only after the optimization of process parameters. The aim of the work was to investigate the microstructure, chemical composition, and hardness changes of laser-welded steels. After laser welding, two zones were generated in the processed materials: a fusion zone and a heat-affected zone. Due to solidification, a refinement of the microstructure occurred in the fusion zone. Examinations of the chemical composition of particular melted areas showed the occurrence of Nb-rich precipitations. The laser welding of steels led to increased hardness in the fusion zone (about 240–530 HV0.3).
Access status: Open Access ,
Comparison among different constitutive equations on investigating tensile plastic behavior and microstructure in austempered ductile iron
(AGH University of Science and Technology Press, 2018) Angella, Giuliano; Zanardi, Franco
The capabilities of different constitutive equations of approximating the tensile flow curves and correlating plastic behavior with the microstructure were investigated in austempered ductile iron ADI 1050. In a previous paper, the microstructure evolution of ADI 1050 during austempering was investigated through quenching the ADI 1050 after 14 increasing austempering times to room temperature. The 14 samples were tensile tested and two classes of constitutive equations were examined in the present paper. The Hollomon-type constitutive equations approximated all of the tensile flow curves of ADI 1050 very well but failed in correlating the plastic behavior with microstructure evolution. Voce-type constitutive equations approximated the tensile flow curves only at high stresses very well but could correlate the plastic behavior with the microstructure evolution of ADI 1050 during austempering excellently. The reason of this success was rationalized in terms of the physical basis of Voce-type equations, while Hollomon-type equations are empirical.
Access status: Open Access ,
Effect of Titanium Alloying of Zn-Al-Cu Alloys for High Pressure Die Casting in Production Conditions
(AGH University Press, 2023) Pasierb, Łukasz; Łakomski, Jan; Figurski, Krzysztof
The paper presents the possibility of the industrial production of Zn4Al3Cu alloy with the addition of 0.41% Ti. Tests are described on the manner of introducing the ZnTi2 master alloy to the alloy, so that the chemical composition of the desirable elements proportion is obtained. The chemical persistence of the Zn4Al3CuTi was determined as low in the conditions of the long heating of the alloy before casting. Tests on the microstructure and mechanical properties of the obtained alloys were also conducted. The strength of the die-cast Zn4Al3Cu alloy was 265 MPa and, when measured on samples taken from the high pressure die-cast, it reached 369 MPa. It was determined that the addition of titanium to the Zn4Al3Cu alloy causes significant refinement of the structure and contributes to the formation of intermetallic phases.
Access status: Open Access ,
Fabrication of surface layer enriched with zinc on AlSi17 aluminium cast alloy by hot-dip galvanizing
(AGH University of Science and Technology Press, 2019) Bucki, Tomasz; Bolibruchová, Dana
The paper deals with the fabrication of the surface layer enriched with Zn on AlSi17 aluminium alloy to modify the microstructure and surface properties of the alloy. The continuous surface layer was fabricated on the AlSi17 substrate by the hot-dip galvanizing of AlSi17 for 15min in a Zn bath heated to 450°C. The thickness of the layer was about 100 ?m. The layer was characterised by a multi-component microstructure containing the regions of a solid solution of Al in Zn and dendrites of a eutectoid composed of a solid solution of Al in Zn and a solid solution of Zn in Al. In the layer, fine particles of Si with a regular shape were distributed. The results indicated that these Si particles formed by the action of Zn on the eutectic Si precipitations in the AlSi17 substrate. In the microstructure, large primary Si crystals and multi-phase precipitations, originating from the substrate, were also observed. The surface layer had much higher microhardness than the AlSi17 substrate. The results showed that hot-dip galvanizing can be used to modify the microstructure and properties of the surface layer of AlSi17. The study indicates the possibility of conducting further research on the fabrication of joints between AlSi17 and other metallic materials using a Zn interlayer fabricated by hot-dip galvanizing.
Access status: Open Access ,
Forming of the microstructure in Fe-C-V alloys
(2011) Kawalec, Magdalena; Fraś, Edward
The study presents the results of microstructural examinations of the volume solidifying Fe-C-V alloys containing carbon in the range of 1.45-2.23% and vanadium in the range of 7.33-15.08%. Attention was focussed on near-eutectic alloys. The Fe-C-V eutectic crystallising in these alloys is composed of ferrite and vanadium carbides of VC1-x type, and as such is included in the group of fibrous eutectics. During research, the experimental eutectic lines were plotted for Fe-C-V alloys, and a formula enabling calculation of the eutectic saturation ratio of these alloys was proposed.
Access status: Open Access ,
Grain size measurement using a semi-automatic calculation tool
(Wydawnictwa AGH, 2023) Mernache, Fatah; Sehisseh, Abdelaziz; Amrane, Amina; Hadji, Said; Melhani, Yasmine; Grine, Mohamed; Messai, Lakhdar
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 $UO_{2}$ 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 ?m. The developed tool, mainly for the purpose of time-saving, allowed us to follow the microstructure (grain size) evolution of the elaborated $UO_{2}$ fuel with different additives.
Access status: Open Access ,
Influence of closed-die hot compaction parameters on selected properties of PM Al-Si-Fe-Cu materials
(2010) Wojtaszek, Marek; Dudek, Piotr
The work presents the results of investigations of the materials obtained by closed-die hot compaction of A117Si5Fe3Cu1.1Mg0.6Zr alloy powder. The influence of temperature and punch unit pressure on the shape of samples, as well as on relative density, selected mechanical properties and microstructure of obtained products, was estimated. The beneficial parameters of hot compaction were determined.
Access status: Open Access ,
Influence of the Addition of Tellurium and Heat Treatment on the Microstructure of Hypoeutectic White Cast Iron
(AGH University Press, 2025) Trela-Przybyło, Alicja; Kawalec, Magdalena; Górny, Marcin
This study investigates how the addition of tellurium and heat treatment affects the microstructure of hypoeutectic white cast iron that has been modified with alloying elements such as titanium, chromium and vanadium. Samples with different chemical compositions were prepared and subjected to a two-step heat treatment process. Microstructural characterisation was performed using optical and scanning electron microscopy. The results show that introducing tellurium significantly affects the morphology of the cementite and carbide phases, causing them to fragment and become more evenly distributed. Furthermore, heat treatment enhanced matrix refinement and promoted phase stability. The combination of tellurium addition and heat treatment produced the most favourable microstructures, characterised by the high dispersion of hard phases within a fine-grained matrix.
Access status: Restricted ,
Materiały dla energetyki jądrowej - mikrostruktura wybranych gatunków staliwa
(Data obrony: 2015-10-30) Tracz, Wojciech Tomasz
Wydział Odlewnictwa
Access status: Open Access ,
Microstructure of TIG welded with selected magnesium alloys
(2014) Tuz, Lechosław; Pańcikiewicz, Krzysztof; Żurek, Zbigniew
An evaluation of the macro- and microstructure of magnesium alloy tungsten arc-welded butt joints is presented in this paper. Al-Zn-Mn magnesium alloys are taken into consideration in the research. Their main alloying elements are zinc and aluminum, respectively. The dendritic microstructure of the base metal is obtained. The analysis shows that achieving good-quality butt joints of magnesium alloys is possible.
Access status: Open Access ,
Microstructure study of fractured polar bear hair for toughening, strengthening, stiffening designs via energy dissipation and crack deflection mechanisms in materials
(2021) Stachewicz, Urszula
Wydział Inżynierii Metali i Informatyki Przemysłowej
Polar bear hair is known for its superior thermal insulation properties protecting from frigid water and freezing weather conditions. However, this microscopy study on polar bear hair is related to the investigation of the crack stopping mechanisms within its structure following the toughening mechanism principle used by nature. The inhomogeneous structure of polar bear hair consists of fiber bundles, tubules, membranes, porous medulla, and cuticle layers. Precisely, these types of material constructions help impact energy dissipation to protect materials before the failure and save animals via its multifunctionality. The multiscale structures are the key to adopting different physical properties in distinct sizes, from thermal insulation to the toughening, strengthening, and stiffening mechanisms in material designs.
Access status: Restricted ,
Mikrostruktura i właściwości stali żaroodpornego HU
(Data obrony: 2014-01-30) Wnuk, Michał Krystian
Wydział Odlewnictwa