Browsing by Subject "magnesium"

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Access status: Open Access ,
An analysis of the features of cast composite materials based on light alloys reinforced by particles
(AGH University of Science and Technology Press, 2022) Dan, Olena Leonìdìvna
Light alloys are widely used in industry and everyday life due to their high physical and mechanical properties, wear and corrosion resistance, as well as low cost. In this regard, the use of light alloys as a basis for composite materials is both justified and expedient. The potential of these materials has not been fully used to this day, despite the growing interest in metal matrix composites and extensive investigations aimed at the development of production technology and the introduction of advanced systems based on light matrices. The article presents a short review of the analysis of the main components of the technology of cast composite materials based on light alloys of aluminum and magnesium reinforced by particles. Particular attention is paid to the choice of the matrix alloy, the type, size and amount of reinforcing particles introduced into it, as well as the thermal-time and kinetic parameters of the process.
Access status: Open Access ,
Effect of texture on deformation mode in magnesium and AZ61 alloy
(Wydawnictwa AGH, 2018) Sułkowski, Bartosz
The effect of the initial texture on the deformation mode and mechanical properties was studied in magnesium and its AZ61 alloy. Both materials had a very similar initial texture. Two cases were investigated: samples with a texture where the basal slip system was blocked, and samples having a texture where the basal slip system was allowed to activate. The samples were deformed by compression at room temperature at a strain rate of 10?3 s?1. It was found that the initial texture had a very strong impact on the deformation mode in magnesium, however, there was no effect of the initial texture on the deformation mode in the case of AZ61. The investigations were compared to simulations of texture evolution using the Taylor model. From the simulations, the Taylor factor and slip system activity were obtained. It was found that, in the case of magnesium, twinning or slip (both basal and non-basal) are the two main deformation modes, while in the case of AZ61, slip is the only main deformation mechanism despite the initial texture. The impact of the initial texture is discussed in more detail in the present study.
Access status: Restricted ,
Magnez i wapń w wodach typu szczawy w Krynicy-Zdrój
(Data obrony: 2017-10-17) Widełka, Waldemar
Wydział Geologii, Geofizyki i Ochrony Środowiska
Krynica-Zdrój położona jest w południowej części Polski na obszarze płaszczowiny magurskiej, w miejscu gdzie stykają się ze sobą dwie strefy facjalne: krynicka i bystrzycka. Występują tutaj głównie szczawy i wody kwasowęglowe strefy hipergenicznej położonej w płytkich partiach fliszu. Są to wody infiltracyjne do których systemem szczelin i nieciągłości dostaje się głębinowy CO2. Typ hydrochemiczny wód to zazwyczaj HCO3-Ca lub HCO3-Ca-Mg, a jony Ca2+, Mg2+, pochodzą z rozpuszczanych skał osadowych, oraz jako produkty wietrzenia skał magmowych. Wody, w których zawartość wspomnianych wcześniej pierwiastków przekracza próg farmakologiczny mają ogromne znaczenie w funkcjonowaniu organizmu człowieka, lecząc ponadto schorzenia układu krążenia oraz układu pokarmowego. Szczawy stosowane są w krenoterapii oraz w balneoterapii w ramach kąpieli leczniczych. Wykorzystywane są również na szeroką skalę w przemyśle rozlewniczym.
Access status: Open Access ,
Methods of introducing alloying elements into liquid magnesium
(2014) Kapinos, Dawid; Augustyn, Bogusław; Szymanek, Marcin
In recent years, magnesium alloys have gained widespread popularity as construction materials. This is due to their low density, high strength properties, and advances in their production technology. Properties of magnesium alloys depend primarily on the type, quantity, and quality of elements present in their composition. It is therefore necessary to carry out research on the further optimisation of the production technology of these alloys. This article presents the results of studies carried out in order to determine the type, form, and parameters of the process of introducing selected alloying elements to magnesium in a manner which enables the manufacture of alloys with predetermined chemical composition. As part of the work, elements such as Al, Zn, Mn, Zr, Si, Cu, Ca, as well as rare earth elements (RE) were introduced into the liquid magnesium. The alloying elements were introduced into the melt at different temperatures in either a metallic form or as master alloys. While conducting studies, respective solubility graphs were plotted for the alloying elements showing the time taken for each element to dissolve to the required form at a specific temperature and concentration. The studies resulted in the development of several techniques of introducing selected alloying elements, which enabled the manufacture of various types of alloys.
Access status: Open Access ,
Microstructural, Fluid Dynamic, and Mechanical Characterization of Zinc Oxide and Magnesium Chloride-Modified Hydrogel Scaffolds
(2024) de Mello Innocentini, Murilo Daniel; Fuzatto Bueno, Bruno Ribeiro; Urbaś, Agnieszka; Morawska-Chochół, Anna
Wydział Inżynierii Materiałowej i Ceramiki
Scaffolds for filling and regeneration of osteochondral defects are a current challenge in the biomaterials field, and solutions with greater functionality are still being sought. The novel approach of this work was to obtain scaffolds with biological active additives possessing microstructural, permeability and mechanical properties mimicking the complexity of natural cartilage. Four types of scaffolds with a gelatin/alginate matrix modified with hydroxyapatite were obtained, and the relationship between modifiers and substrate properties was evaluated. They differed in the type of second modifier used, which was hydrated MgCl2 in two proportions, ZnO, and nanohydroxyapatite. The samples were obtained by freeze-drying using two-stage freezing. Based on microstructural observations combined with X-ray microanalysis, the microstructure of the samples and the elemental content were assessed. Permeability and mechanical tests were also performed. The scaffolds exhibited a network of interconnected pores and complex microarchitecture, with lower porosity at the surface (15±7 to 29±6%) and higher at the center (67±8 to 75±8%). The additives had varying effects on the pore size and permeability of the samples. ZnO yielded the most permeable scaffolds (5.92×10-11 m2), whereas nanohydroxyapatite yielded the scaffold with the lowest permeability (1.18×10-11 m2), values within the range reported for trabecular bone. The magnesium content had no statistically significant effect on the permeability. The best mechanical parameters were obtained for ZnO samples and those containing hydrated MgCl2. The scaffolds properties meet the criteria for filling osteochondral defects. The developed scaffolds follow a biomimetic approach in terms of hierarchical microarchitecture and mechanical parameters, as well as the chemical composition. The obtained composite materials have potential as biomimetic scaffolds for regeneration of osteochondral defects.
Access status: Restricted ,
Synteza i charakterystyka właściwości sorpcyjnych wybranych związków metaloorganicznych
(Data obrony: 2016-10-06) Kudła, Paulina
Wydział Geologii, Geofizyki i Ochrony Środowiska
Celem pracy była synteza i charakterystyka strukturalna trzech wybranych związków metaloorganicznych z grupy Me2(BDC)2(Dabco), gdzie za Me podstawiono Ni, Zn i Mg, a następnie określenie ich właściwości sorpcyjnych. Związki te powstały w wyniku połączenia azotanów wymienionych metali z kwasem tereftalowym i związkiem Dabco (1,4-diazabicyklo[2.2.2]oktan) w obecności dimetyloformamidu w odpowiednich warunkach temperatury i ciśnienia. Charakterystyki struktury materiałów dokonano za pomocą metody dyfrakcji rentgenowskiej, spektroskopii w podczerwieni, analizy termicznej oraz mikroskopii skaningowej. Badania wykazały, że powstałe związki charakteryzują się strukturą krystaliczną, a kryształy przybierają formę igieł (Ni-MOF), sześcianów (Zn-MOF) oraz płytek (Mg-MOF). Związki te są stabilne do temperatury około 140oC (Ni, Zn-MOF) i 240oC (Mg-MOF). Analiza właściwości sorpcyjnych wykazała jednak, że związki są niestabilne pod względem masy i mimo ich odgazowania nie udało się uzyskać jednoznacznych wyników. Badania wskazują jednak na to, że najlepszym sorbentem jest Ni-MOF, a związek Mg-MOF nie nadaje się do pełnienia roli sorbentu.