Wyniki wyszukiwania - BazTech

1

3D-printed prototypes of ABS gears with improved durability

Sobolak Mariusz, Połowniak Piotr

Polimery

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2025

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Vol. 70, nr 7-8

467--473

EN

The effect of thermal treatment (above the glass transition temperature) on the durability of ABS gears obtained using the FFF method was investigated. During processing, the gears rotated around their axis, which prevented asymmetric deformations resulting from gravity-induced material flow and ensured uniform surface heating. The tests continued until the gears failed, gradually increasing the load. Thermal treatment increased the gears’ durability by over 20%.

PL

Zbadano wpływ obróbki termicznej (powyżej temperatury zeszklenia) na trwałość przekładni kół zębatych z ABS otrzymanych metodą FFF. Podczas obróbki koła obracały się dokoła własnej osi, co pozwalało uniknąć niesymetrycznych odkształceń w wyniku płynięcia tworzywa pod wpływem grawitacji i gwarantowało równomierne nagrzewanie powierzchni. Badania prowadzono do momentu uszkodzenia kół, zwiększając stopniowo obciążenie. Obróbka termiczna zwiększała o ponad 20% trwałość kół zębatych.

2

Technological research of calcinated dolomite ores as intermediates for metal magnesium production

Bekényiová Alexandra, Danková Zuzana, Kollová Zuzana, Fedorová Erika, Bačo Pavel, Briančin Jaroslav, Čechovská Katarína

Geology, Geophysics and Environment

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2025

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Vol. 51, no. 2

193--203

EN

The current work investigates the differences between four types of calcinated dolomite samples as suitable intermediates for subsequent silicothermic reduction of metal magnesium by simultaneous differential thermal analysis (DTA) /thermogravimetric analysis (TG). The results of the DTA/TG analysis showed the least significant differences at the temperature endotherms with no weight loss on the TG curves at a temperature of 1373 K for the calcined dolomite sample TR-1 from Trebejov deposit. The most significant difference on the DTA curves was detected for the calcinated sample KRA-1 (deposit Kraľovany), which is connected with the hydration activity of the sample. According to the results of the chemical analyses, annealing products of all samples fulfilled two of the three conditions, namely a molecular ratio of CaO:MgO and an impurity content below 2.5% for their subsequent use as feedstocks in the silicothermal process for the preparation of metallic magnesium. Subsequently, the experimental test of silicothermic reduction of magnesium of calcinated sample ST-1 in a flowing argon atmosphere was investigated by EDX analysis. The results indicate that the prepared magnesium sample analysed by EDX – point and mapping analysis confirmed the presence of magnesium totalling 91% despite the failure to reach the temperature in the furnace required for the reduction of Mg.

3

Phase Transition Enthalpy, and Oxidation Binding Energy of Hydrothermally Synthesized BaTiO3 Nanopowders via Pre-annealing and Sintering Processes

Lee Jongbeom, Jeong Jinyoung, Jung Jaehoon, Jeong Haguk

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 2

733--736

EN

Hydrothermally synthesized BaTiO3 nanopowders pre-annealed at high temperatures of 900℃ for 4 h in the air were sintered at 1200℃ for 2 h in N2 atmosphere, and their cubic-tetragonal transformation, transition enthalpy, and binding energy (BE) were investigated. The nanopowder crystal structures changed from cubic to tetragonal during annealing or sintering at temperatures above 900℃ with constant tetragonality (1.01). With increasing pre-annealing temperature, the cubic-tetragonal transition enthalpy decreased, and the differential scanning calorimetry (DSC) peak broadened. Pre-annealing in the air increased BE and nonchemical energy distribution in the BaTiO3 powder, reducing the transition enthalpy and sharpness of the DSC curve. This was ascribed to the differences in imperfections from oxidation, such as the density and uniform distribution of Ba among the samples, resulting from the BE shifts of the Ba 3d, Ti 2p and O 1s peaks to higher values in the XPS spectra.

4

Microstructure and Mechanical Properties of Layered Aluminum Alloy Sheets Fabricated by Multi-Stack ARB Process

Lee Seong-Hee

Archives of Metallurgy and Materials

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2025

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Vol. 70, iss. 3

1143--1146

EN

A layered Al sheet was fabricated by three cycles (c) of multi-stack accumulative roll-bonding (ARB) using commercial AA1050, AA5052, and AA6061 alloy sheets, and then annealed. The as-ARBed Al sheet showed ultrafine grained (UFG) structure, with average grain diameter of 1.07 μm. Through up to 250℃, the annealed sheets still showed UFG structure, above 300℃, they exhibited heterogeneous structure, in which due to static recrystallization, both ultrafine and coarse grains coexisted. As the number of ARB cycles increased, the tensile strength increased, after 3c, they reached 390 MPa, 2.4 times the average value of the starting materials. The changes in microstructure and mechanical properties of the multi-layered Al sheet with annealing are discussed in detail, and compared to those of the 2c ARBed materials by the previous study.

5

Non-oriented electrical steel under bending and annealing effects

Hebri Mohamed Amine, Bauw Grégory, Lecointe Jean-Philippe, Duchesne Stéphane, Fawaz Sara, Zito Gianluca, Arslane Idir, Abdelli Abdenour, Maier Adrien, Vandeginen Clément

Archives of Electrical Engineering

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2025

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Vol. 74, nr 2

447--461

EN

This study investigates the impact of bending stress and annealing on the magnetic performance of 3% silicon-iron non-oriented electrical steel (NOES). Samples were bent into diameters of 120 mm, 160 mm, and 200 mm representing the internal, average and external diameters of an axial flux machine and their magnetic properties, including permeability and iron losses, were measured. The results show that bending stress significantly degrades these properties, with smaller diameters causing greater deterioration. Annealing treatments were applied to restore performance, with partial or full recovery depending on the annealing temperature. A finite element (FE) model is proposed to account for the effects of bending on magnetic performance, incorporating three regions with distinct magnetic properties corresponding to different bending radii, using the commercial software JMAG-Designer. The study’s findings provide valuable insights into the effects of bending and annealing on NOES, offering potential applications in toroidal transformers and axial flux machines.

6

Influence of the annealing temperature of the shape memory alloy actuator on its thermal characteristics

Kuś Krzysztof, Frączyk Adam

Budownictwo o Zoptymalizowanym Potencjale Energetycznym

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2024

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Vol. 13

50--60

EN

Shape memory alloys (SMA) are used in different areas of engineering and science thanks to their unique properties. They also continue to be an innovative material for the sustainable construction industry. In this study, a commercial helical-type SMA spring actuator was investigated by subjecting it to annealing at various parameters. The thermal shape memory properties were evaluated by means of the DSC method. In most cases, the higher the annealing temperatures for the material were in the range up to 595°C, the lower the transformation temperatures. As the DSC runs showed, a different character of the changes especially in characteristic temperatures, was observed for annealing temperatures above 600°C. The results showed that the different annealing temperatures, and even the method of cooling, provide a wide range of possibilities to control the SMA spring reaction – transformation behaviour and temperatures. Such treatment can be a simple technical procedurę used for the preparation of the selected SMA functional properties if required. This means that the same SMA element can be reused without having to source a new one. This may be desirable from the point of view of sustainability.

7

Mechanical Properties of P92 Welded Joint after 3000 Hours of Annealing at 600 and 650°C

Sówka Karol, Purzyńska Hanna, Sroka Marek, Puszczało Tomasz, Zieliński Adam

Archives of Metallurgy and Materials

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2024

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Vol. 69, iss. 2

705--709

EN

P92 steel is a modern martensitic heat-resistant steel currently used for seamless products for pressure equipment operating in supercritical operating parameters. The paper presents the results of a study on the strength properties and structure of a P92 steel welded joint used for pressure components of power units. The paper presents an assessment of the suitability for further operation of both the parent material and a circumferential similar welded joint of finished products in the form of P92 steel pipes after annealing for 3000 hours at 600 and 650°C. Annealing at 650°C results in faster increase in the size of the precipitates and their coagulation along grain boundaries of former austenite and martensite laths. The changes in mechanical properties were compared in relation to the state of the structure of the parent material and the material of the welded joint. Quantitative analysis of M23C6 precipitates was also carried out.

8

Mechanism and growth kinetics of Al3Ti phase in fifteen-layered Ti Gr.1/A1050 clads produced with the explosive welding technique

Janusz-Skuza Marta, Bigos Agnieszka, Kwiecień Izabella, Wierzbicka-Miernik Anna, Szulc Zygmunt, Wojewoda-Budka Joanna

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 3

art. no. e155, 2024

EN

This study was dedicated to the detailed characterization of the microstructural changes and the phase analysis of the interfaces formed in explosive welding of multilayered Ti Gr.1/A1050 clads. The significant effect of the detonation source localization on the microstructure of the welded materials interfaces after collision, and consequently on the diffusion processes induced by the elevated temperature was showed. Annealing process at 550 °C for series of time intervals of the Ti/Al clad allowed to determine the growth mechanism of the Al3Ti phase formed along particular interfaces. Moreover, the microstructure observations and calculations evidenced different growth mechanisms related to the localization of the Ti/Al interface in respect to the detonation source.

9

A review on the effect of various rolling regimes (cryo, cold, warm, hot) and post‑annealing on high‑entropy alloys: microstructure evolution, deformation mechanisms, and mechanical properties

Tayyebi Moslem, DerakhshaniMolayousefi Mahdi

Archives of Civil and Mechanical Engineering

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2024

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Vol. 24, no. 1

art. no. e16, 2024

EN

Despite their complex composition, high-entropy alloys (HEAs) have a simple structure and have been extensively researched for their ability to achieve unique properties through thermo-mechanical processing (TMP). This review studies the effects of different rolling regimes and post-annealing on single and multiphase HEAs, analyzing how TMP leads to microstructural changes and improved mechanical properties. The rolling changes the shape and utilizes different mechanisms determined by the rolling temperature to strengthen the raw materials, thus affecting the HEAs' properties. The microstructural evolution of HEAs during annealing is affected by various parameters such as annealing time, annealing temperature, and heating rate, which impact the strength–ductility combination of HEAs. According to the literature, cryogenic rolling (cryo-rolling), as opposed to cold rolling, provides greater strengthening. This is due to the faster microstructural evolution kinetics in cryo-rolling. Thus, cryo-rolling enhances the strengthening by activating deformation twinning at earlier stages through the intersection of twins and more shear banding, which is preferred to microbands for HEAs with low stacking fault energy (SFE). Rolling at high temperatures is the most suitable approach for HEAs with low workability. Warm and hot rolling enable microstructure evolution through deformation mechanisms, including grain growth, recovery, recrystallization, and phase transformation based on the process temperature. The ratio of recovery to recrystallization depends on temperaturę and SFE, with recovery dominating in alloys with high SFE and at lower rolling temperatures, while recrystallization is more prevalent for alloys with low SFE and at higher temperatures, leading to specific ductility–strength synergy.

10

Wyniki badań odpowiedzi gazochromowej na wodór cienkich warstw WO₃ naniesionych za pomocą parowania wiązką elektronową

Weichbrodt Wiktoria, Mazur Michał

Biuletyn Wojskowej Akademii Technicznej

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2023

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Vol. 72, nr 4

91--100

PL

Wśród materiałów chromowych dużym zainteresowaniem cieszy się trójtlenek wolframu (WO₃ ). Jest to bezbarwny półprzewodnik charakteryzujący się brakiem toksyczności oraz wysoką stabilnością chemiczną. WO₃ wykazuje właściwości gazochromowe, co oznacza, że materiał ulega odwracalnym zmianom właściwości optycznych pod wpływem gazu. te właściwości sprawiają, że trójtlenek wolframu jest odpowiednim materiałem do zastosowań czujnikowych. W pracy przedstawiono wyniki badań właściwości strukturalnych i optycznych cienkich warstw trójtlenku wolframu wytworzonych metodą parowania wiązką elektronową i wygrzewanych w temperaturze od 400 do 800°C. Właściwości optyczne, w tym również właściwości gazochromowe, określono na podstawie widm transmisji światła w atmosferze zawierającej wodór o stężeniu od 50 do 500 ppm. Badano właściwości optyczne warstw WO₃ zarówno z naniesioną warstwą katalizatora w postaci palladu, jak i bez tej warstwy. Wygrzewanie próbek w temperaturze powyżej 400°C spowodowało krystalizację warstw, a dalsza modyfikacja poprocesowa w temperaturze 800°C spowodowała sublimację warstwy, stworzenie wysp krystalicznych ziaren o dużych rozmiarach oraz znaczne pogorszenie właściwości optycznych. Zmiana współczynnika transmisji światła nastąpiła we wszystkich próbkach z naniesioną warstwą katalizatora po ekspozycji warstw na wodór. Na podstawie zaprezentowanych wyników badań stwierdzono, że najlepszymi właściwościami gazochromowymi charakteryzują się warstwy wygrzewane w temperaturze 400°C, ponieważ wykazują największą zmianę transmisji światła pod wpływem wodoru. W pracy potwierdzono możliwość poprawy odpowiedzi gazochromowej cienkich warstw trójtlenku wolframu wytworzonych metodą parowania wiązką elektronową za pomocą wygrzewania, co zgodnie z bieżącą wiedzą nie zostało wcześniej osiągnięte.

EN

Among chromogenic materials, tungsten trioxide (WO₃) is of great interest. it is a colourless semiconductor characterised by a lack of toxicity and high chemical stability. WO₃ exhibits gasochromic properties, meaning that the material undergoes reversible changes in optical properties when it is exposed to gas. These properties make tungsten oxide a suitable material for sensing applications. This paper presents the results of an analysis of the surface, structural and optical properties of tungsten oxide thin films fabricated by electron beam evaporation and annealed at 400°C to 800°C. optical properties, including gasochromic properties, were determined from light transmission spectra in an atmosphere containing hydrogen at the concentrations ranging from 50 ppm to 500 ppm. The optical properties of WO₃ films without and with a palladium catalyst layer are applied. annealing the samples at temperatures above 400°C resulted in crystallisation of the layers, and further post-process modification at 800°C led to sublimation, the formation of islands of crystalline grains of large size and a significant deterioration in optical properties. a change in the light transmission coefficient occurred for all samples with the catalyst layer applied after the introduction of a hydrogen-argon mixture. Based on the results, it can be concluded that the layers annealed at 400°C had the best gasochromic properties due to the greatest changes in light transmission under hydrogen. The study confirms that it is possible to improve the gasochromic response of tungsten trioxide thin films produced by electron beam evaporation using thermal modification, which, to the best of current knowledge, has not previously been achieved.

11

Effect of Annealing and Silver Content on the Mechanical Properties of Zn-Al-Ag Alloys

Rubio-Padrón Miguel Angel, Echartea-Reyes Olga Alondra, Calles-Arriaga Carlos A., Rocha-Rangel Enrique

Archives of Metallurgy and Materials

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2023

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Vol. 68, iss. 4

1467--1471

EN

Through the powder metallurgy technique, alloys of the eutectic composition of the Zn-Al system were manufactured (22.3 wt.%Al), reinforced with Ag additions (0.5, 1, 2.5, 5 wt.%), with subsequent annealing heat treatment at three different temperatures; 100, 150 and 200°C for 1 hr. X-ray diffraction, optical microscopy and mechanical tests were performed on the resulting samples. The addition of Ag favors the formation of alpha and beta compounds with Al and Zn respectively, which improves the compressive strength of the alloy. However, with the presence of Ag the hardness is decreased. On the other hand, the application of an annealing heat treatment, shows no significant effect on the evaluated properties of the alloy. The microstructure of the alloys resulted in the presence of very small grains smaller than 1 mm and with rounded morphology.

12

Effect of high temperature annealing on the microstructure evolution and hardness behavior of the Inconel 625 superalloy additively manufactured by laser powder bed fusion

Dubiel Beata, Gola Kewin, Staroń Sylwia, Pasiowiec Hubert, Indyka Paulina, Gajewska Marta, Zubko Maciej, Kalemba-Rec Izabela, Moskalewicz Tomasz, Kąc Sławomir

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 4

art. e249, s. 1--20

EN

Additive manufacturing of Inconel 625 components attracts great interest due to its ability to produce parts with complex geometries that are needed for high-temperature applications in the aerospace, energy, automotive and chemical industries. To take full advantage of the potential of additive manufacturing, an in-depth understanding of the effects of prolonged high-temperature annealing on microstructure and hardness evolution is needed. Previous research in this field has mainly focused on a limited range of temperature and time. This study aims to determine the effect of prolonged high-temperature annealing on the evolution of intermetallic phases and carbides, as well as changes in the dislocation substructure of Inconel 625 superalloy additively manufactured by laser powder bed fusion subjected to stress relief annealing and subsequent isothermal annealing at a temperature up to 800°C for 5-500 h. The microstructure development is correlated with hardness behaviour. It is determined that the microstructure evolution proceeds in four stages with temperature and time increase. In the initial stress-relieved condition, a cellular microstructure with nano-sized precipitates of the Laves phase and NbC carbides at the cell walls occurs, and hardness is equal to 300 HV10. In the 1st stage of the microstructure evolution, the γ'' phase particles precipitate on the cell walls, which results in hardening up to 383 HV10 in the specimen annealed at 700°C for 5 h. The 2nd stage involves the precipitation of the γ'' phase both on the cell walls and inside the cells, as well as the formation of dislocation networks, which contribute to the softening effect and hardness drop to 319 HV10. In the 3rd stage, at temperature 700 and 800°C, the δ phase, M23C6 carbides, and the Laves phase precipitate and grow, and the sub-grain boundaries are formed. The hardness ...

13

Influence of Annealing Treatment on Deep Drawing Behavior of Q235 Carbon Steel /410/304 Stainless Steels Three-Layer Composite Plate

Lv Zehua, Zhang Zhixiong, Han Jianchao, Wang Tao

Archives of Metallurgy and Materials

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2022

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Vol. 67, iss. 2

421--433

EN

Effect of annealing treatment on deep drawing behavior of hot-rolled Q235 carbon steel/410/304 stainless steel three-layer composite plate was investigated. Deep drawability of the unannealed composite plates exhibits a sharp difference for various contact surfaces with the die. The limit drawing ratio (LDR) of the composite plate with the carbon steel contacting the die is 1.75, while it is 1.83 with the stainless steel contacting the die due to the different mechanical responses to the tensile stress at the corner of the die. After annealing at 900°C for 2 h, however, the deep drawabilities of the composite plates both for various contact surfaces with the die are significantly improved and becomes almost identical, which are attributed to the stress relief, the enhanced ductility and the improved interface bonding strength of the hot-rolled component plates during annealing.

14

Przemiany fazowe zachodzące w układach Fe/NH3/H2 oraz Fe-N

Michalski Jerzy, Frączek Tadeusz

Inżynieria Powierzchni

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2021

|

nr 1

5--13

PL

W artykule omówiono na podstawie literatury przemiany fazowe w azotkach żelaza wytworzonych na proszkach żelaza i na próbkach litych. Przedstawiono przemiany fazowe podczas wyżarzania w atmosferze NH3/H2 oraz w atmosferach obojętnych. Wskazano podobieństwo przemian fazowych w różnych atmosferach zastosowanych podczas wyżarzania. Opisano warunki przemian fazowych w azotkach żelaza podczas wyżarzania w atmosferze NH3/H2, w argonie oraz próżni. Przemiany fazowe zachodzące podczas wyżarzania w atmosferze NH3/H2 są odwracalne, występuje w nich zjawisko histerezy. Podczas przemiany fazowej ɛ→γ’ w atmosferze NH3/H2 do momentu zakończenia przemiany ma miejsce emisja azotu do atmosfery. Natomiast niezbędnym warunkiem przebiegu przemiany γ’→ɛ jest strumień azotu z atmosfery do powierzchni. Przemiany fazowe podczas wygrzewania w próżni i argonie są nieodwracalne. Podczas ciągłego ogrzewania azotowanych proszków żelaza z szybkością 30 K/min w próżni i argonie mogą wystąpić dwie przemiany fazowe, którym nie towarzyszy ubytek masy. Pierwsza, (α+γ’)→γN w zakresie temperatur 540÷550°C w próżni i 620÷630°C w argonie oraz druga, (γ+γ’)→ɛ w zakresie 610÷620°C w próżni i 690÷710°C w argonie. W przypadku nagrzewania w argonie początek ubytku masy rejestrowano w temperaturze ok. 860°C, natomiast w próżni kończy się w tej temperaturze odazotowanie austenitu azotowego γN. Podczas wyżarzania w temperaturze 360ºC przemianie fazowej ɛ→γ’ w warstwie ɛ/γ’ towarzyszy wzrost grubości fazy γ’, który odbywa się kosztem grubości strefy ɛ, przy czym całkowita grubość warstwy po przemianie jest taka sama, jak jej grubość w stanie wyjściowym. W temperaturze 420ºC po zakończonej przemianie ɛ→γ’, utworzona monofazowa warstwa γ’ jest grubsza od warstw ɛ/γ’ w stanie wyjściowym.

EN

In the article, based on the literature, the phase changes in iron nitrides on iron powders and on solid samples were discussed. Phase transformations in NH3/H2 atmosphere and in inert atmospheres are discussed. The similarity of phase transformations in different atmospheres used during annealing were indicated. The conditions of phase transformations in iron nitrides during annealing in NH3/H2 atmosphere, argon and vacuum were discussed. Phase transformations occurring during annealing in the NH3/H2 atmosphere are reversible and there is a hysteresis phenomenon. During the phase transformation ɛ→γ' in the NH3/H2 atmosphere until the transformation is completed, nitrogen emission to the atmosphere takes place. On the other hand, the condition for the course of the transformation of γ'→ɛ is the nitrogen flow from the atmosphere to the surface. Phase changes during heating in vacuum and argon are irreversible. During continuous heating at a rate of 30 K / min in vacuum and argon, nitrided iron powders, two phase transformations may occur, which are not accompanied by weight loss, the first (α+γ') →γN in the temperature range 540÷550°C in a vacuum and 620÷630°C in argon and the second (γ+γ') →ɛ in the range of 610÷620°C in vacuum and 690÷710°C in argon. In the case of heating in argon, the onset of weight loss was recorded at a temperature of about 860°C. Whereas in vacuum the denitration of nitrogen austenite γN ends at this temperature. During annealing at the temperature of 360°C, the phase change ɛ→γ′ in the ɛ/γ′ layer is accompanied by an increase in the thickness of the γ′ phase, which is at the expense of the thickness of the ɛ zone, while the total thickness of the layer after the transformation is the same as its initial thickness. At the temperature of 420°C, after the completion of the γ′ transformation, the formed monophasic layer γ′ is thicker than the ɛ/γ′ layers in the initial state.

15

Assessment of the properties of HAp micropowders after ion exchange process in silver nitrate solution

Głuszek Marta, Świrska Zuzanna, Kaczorowski Witold, Januszewicz Bartłomiej, Wrotniak Maciej

Engineering of Biomaterials

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2021

|

Vol. 24, no. 161

15--20

EN

Bioceramic materials, such as hydroxyapatite (HAp), are characterized by high biocompatibility in the presence of tissues and body fluids without causing toxic or allergic reactions. Hydroxyapatite, due to its similarity to structures found in bones, is used both in the form of powders, e.g. as additives to bone cements, and implants coatings. However, this material is not characterized by antimicrobial properties, therefore attempts are made to improve its properties by introducing additional elements into the hydroxyapatite structure. Thanks to HAp’s high ion-exchange ability, silver can be introduced into its structure. The calcium ions present in the HAp structure can be easily replaced by silver ions to create a material endowed with high biocompatibility and antibacterial properties. The presented study is based on the analysis of the morphology of the modified powders via scanning electron microscopy (SEM), their chemical composition via X-ray energy dispersive spectroscopy (EDS) and chemical structure via X-ray diffraction (XRD) and Raman spectroscopy. The powders obtained through the ion exchange were mixtures of silver phosphates Ag3PO4 and HAp. The highest silver content was found in the sample modified with a 1M concentration of AgNO3 in the aqueous solution. It was also determined that the annealing of the obtained powders under vacuum at 800°C resulted in the formation of metallic silver and a change in the structure of HAp to β-TCP.

16

Change In Microstructure and Mechanical Properties Of Four-Layer Stack ARB Processed Complex Aluminum Sheet with Annealing

Jo Sang-Hyeon, Lee Seong-Hee

Archives of Metallurgy and Materials

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2021

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Vol. 66, iss. 3

765--770

EN

The four-layer stack accumulative roll bonding (ARB) process using AA1050, AA5052 and AA6061 alloy sheets is performed up to 2 cycles without a lubricant at room temperature. The sample fabricated by the ARB is a multi-layer complex aluminum alloy sheet in which the AA1050, AA5052 and AA6061 alloys are alternately stacked to each other. The changes of microstructure and mechanical properties with annealing for the-ARBed aluminum sheet are investigated in detail. The as-ARBed sheet shows an ultrafine grained structure, however the grain diameter is some different depending on the kind of aluminum alloys. The complex aluminum alloy still shows ultrafine structure up to annealing temperature of 250℃, but above 275℃ it exhibits a heterogeneous structure containing both the ultrafine grains and the coarse grains due to an occurrence of discontinuous recrystallization. This change in microstructure with annealing also has an effect on the change of the mechanical properties of the sample. Especially, the specimen annealed at 300℃ represents abnormal values for the strength coefficient K and work hardening exponent n value.

17

Phase transformations in the nitrided layer during annealing under reduced pressure

Frączek Tadeusz, Michalski Jerzy, Kucharska Barbara, Opydo Michał, Ogórek Marzena

Archives of Civil and Mechanical Engineering

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2021

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Vol. 21, no. 2

146--156

EN

The article presents studies of phase transformations taking place in surface layers of nitrided steels as a result of their annealing at 520 °C for 5 and 10 h. Two steel grades were tested, the unalloyed AISI 1085 and the low-alloy AISI 52100. As a result of glow discharge nitriding, at 570 °C/5 h and 540 °C/12 h, respectively, nitrided layers were produced on the steels, consisting of a surface layer of iron nitrides with the structure of ε + γ′ and γ′ and of similar thickness 25. The study showed that during 5 h of annealing at 520 °C, the iron nitride layer already decomposed, which was documented by the analysis of chemical composition and X-ray analysis of the surface layers of steel. Comparative studies on the hardness distribution of surface layers of nitrided as well as nitrided and subsequently annealed AISI 52100 steels showed that after both 5 and 10 h of annealing, the hardness depth profiles were very similar and the effective thickness of the diffusion layer did not change. The results obtained enabled the demonstration that the emission of nitrogen into the atmosphere during annealing of nitrided steels is not accompanied by diffusion of nitrogen into the base layer. This proves that the iron nitride layer is not a source of nitrogen for the diffusion layer during annealing at reduced pressure.

18

The affinity for dialysate species of thermally modified titania nanotubes under static and dynamic conditions

Jędrzejewska Aleksandra, Pasik Kamila, Nycz Marta, Arkusz Katarzyna

Acta of Bioengineering and Biomechanics

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2021

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Vol. 23, no. 4

95--105

EN

Purpose: During the dialysis process, hemolysis is the most frequently occurring problem to solve. Titanium dioxide nanotubes (TNTs) can be considered as a material preventing hemodialysis or blood species deposition thanks to their unique properties, i.e., hydrophilicity, smooth surface, and antibacterial. The purpose of this work was the electrochemical, chemical, and morphological characteristics of the TNTs and the evaluation of the possibility of using them as filter parts in dialysis techniques. Methods: The tests were carried out on as-formed TNTs with a diameter of 50 ± 5 nm and 1000 ± 100 nm in height, and TNTs thermally modified in air atmosphere temperatures ranging from 350 to 550 °C. Electrochemical and microscopic analyses were performed both in the static and dynamic system of dialysis fluid (flow rate: 250 cm3/min). Additionally, deposition or damage of blood cells was specified during the ex vivo dialysis experiment. Results: Obtained results proved relationship between electrochemical properties of TNTs and the method of their modification. The results demonstrated that the TNTs annealed at 450 °C TNTs can be potentially applied for constructions dialysis membrane in the hemodialysis area due to their most stable stationary potential in dialysate, the highest value of impedance modulus, and the most favourable electrokinetic properties. Additionally, it was confirmed that annealed process causes improvement of corrosion resistance and protective properties for TNTs in the dialysis fluid. Conclusions: The result allowed for the conclusion that annealing is responsible for reduction of adsorption properties of TNTs, though this titanium dioxide nanotube still can be used as filter part in haemodialysis.

19

Effects of annealing parameters on phase, structure and thermochromic properties of VO2 (M) derived from nanostructured VO2(B)

Barra Hamdi Muhyuddin, Chen Soo Kien, Tamchek Nizam, Talib Zainal Abidin, Lee Oon Jew, Tan Kar Ban

Materials Science Poland

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2020

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Vol. 38, No. 4

661--666

EN

Synthesis of thermochromic VO2 (M) was successfully done by annealing hydrothermally-prepared VO2 (B) at different temperatures and times. Conversion of the metastable VO2 (B) to the thermochromic VO2 polymorph was studied using thermogravimetric analyzer (TGA) under N2 atmosphere. Moreover, the phase and morphology of the synthesized samples were studied using X-ray diffraction (XRD) and field-emission scanning electron microscopy (FE-SEM), respectively. Accordingly, the XRD scans of all the annealed samples exhibited the presence of monoclinic VO2 (M), while the FE-SEM images of the samples showed the formation of nanorods and nanospheres, particularly those heated at high temperatures (650 °C and 700 °C). Meanwhile, differential scanning calorimetry (DSC) was used to measure the phase transition temperature (tc), hysteresis, and enthalpy of the prepared VO2. Based on these results, all samples displayed a tc of about 66 °C. However, the hysteresis was high for the samples annealed at lower temperatures (550 °C and 600 °C), while the enthalpy was very low for samples heated at lower annealing time (1.5 h and 1 h). These findings showed that crystallinity and nanostructure formation affected the thermochromic properties of the samples. In particular, the sample annealed at 650 °C showed better crystallinity and improved thermochromic behavior.

20

Deposition time and annealing effects on morphological and optical properties of ZnS thin films prepared by chemical bath deposition

Chabou N., Birouk B., Aida M. S., Raskin J. P.

Materials Science Poland

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2020

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Vol. 38, No. 4

508--517

EN

Nanocrystalline zinc sulfide (ZnS) thin films are prepared on glass substrates by chemical bath deposition (CBD) method using aqueous solutions of zinc chloride, thiourea ammonium hydroxide along with non-toxic complexing agent tri-sodium citrate in alkaline medium at 80 °C. The deposition time and annealing effects on the optical and morphological properties are studied. The morphological, compositional, and optical properties of the films are investigated by scanning electron microscopy (SEM), X-ray energy dispersive spectroscopy (EDAX) and UV-Vis spectroscopy. SEM micrographs exhibit uniform surface coverage. UV-Vis (300 nm to 800 nm) spectrophotometric measurements show transparency of the films (transmittance ranging from 69 % to 81 %), with a direct allowed energy band gap in the range of 3.87 eV to 4.03 eV. After thermal annealing at 500 °C for 120 min, the transmittance increases up to 87 %.