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Microstructure evolution of pure titanium during hydrostatic extrusion

Wojtas Daniel, Maj Łukasz, Wierzbanowski Krzysztof, Jarzębska Anna, Chulist Robert, Kawałko Jakub, Trembecka-Wójciga Klaudia, Bieda-Niemiec Magdalena, Sztwiertnia Krzysztof

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 1

art. no. e9, 2023

EN

Regarding severely deformed materials of potentially high applicability in various industry branches, their microstructure evolution during processing is of vast significance as it enables to control or adjust the most essential properties, including mechanical strength or corrosion resistance. Within the present study, the microstructure development of commercially pure titanium (grade 2) in the multi-stage process of hydrostatic extrusion has been studied with the use of the well-established techniques, involving electron backscatter diffraction as well as transmission electron microscopy. Microstructural deformation-induced defects, including grain boundaries, dislocations, and twins, have been meticulously analyzed. In addition, a special emphasis has been placed on grain size, grain boundary character as well as misorientation gradients inside deformed grains. The main aim was to highlight the microstructural alterations triggered by hydroextrusion and single out their possible sources. The crystallographic texture was also studied. It has been concluded that hydrostatically extruded titanium is an exceptionally inhomogeneous material in terms of its microstructure as evidenced by discrepancies in grain size and shape, a great deal of dislocation-type features observed at every single stage of processing and the magnitude of deformation energy stored. Twinning, accompanied by grain subdivision phenomenon, was governing the microstructural development at low strains; whereas, the process of continuous dynamic recrystallization came to the fore at higher strains. Selected mechanical properties resulting from the studied material microstructure are also presented and discussed.

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A comprehensive review of graphene‑based aerogels for biomedical applications. The impact of synthesis parameters onto material microstructure and porosity

Trembecka-Wójciga Klaudia, Sobczak Jerzy J., Sobczak Natalia

Archives of Civil and Mechanical Engineering

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2023

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Vol. 23, no. 2

art. no. e133, 2023

EN

Graphene-based aerogels (GA) have a high potential in the biomedical engineering field due to high mechanical strength, biocompatibility, high porosity, and adsorption capacity. Thanks to this, they can be used as scaffolds in bone tissue engineering, wound healing, drug delivery and nerve tissue engineering. In this review, a current state of knowledge of graphene (Gn) and graphene oxide (GO) aerogels and their composites used in biomedical application is described in detail. A special focus is paid first on the methods of obtaining highly porous materials by visualizing the precursors and describing main methods of Gn and GO aerogel synthesis. The impact of synthesis parameters onto aerogel microstructure and porosity is discussed according to current knowledge. Subsequent sections deal with aerogels intended to address specific therapeutic demands. Here we discuss the recent methods used to improve Gn and GO aerogels biocompatibility. We explore the various types of GA reported to date and how their architecture impacts their ultimate ability to mimic natural tissue environment. On this basis, we summarized the research status of graphene-based aerogels and put forward the challenges and outlook of graphene-based aerogels dedicated to biomedical usage especially by formation of joints with biocompatible metals.

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Laser modified functional carbon-based coatings on titanium substrate for cardiac tissue integration and blood clotting inhibition

Major Roman, Ostrowski Roman, Surmiak Marcin, Trembecka-Wójciga Klaudia, Lackner Jurgen

Engineering of Biomaterials

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2020

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Vol. 23, no. 155

22-31

EN

The work focused on developing functional coatings on titanium substrates that would facilitate the integration with the cardiac tissue and with a specific form of connective tissue like blood. Surface modifications consisted in the laser evaporation of part of the biocompatible layer, thus creating a suitable environment for a particular tissue. For the myocardium integration, the metal surface was refined by biohemocompatible coatings. Such surfaces were the starting point for further modifications in the form of channels. The channeled surfaces enabled a controlled cell migration and proliferation. The interaction of endothelial cells with the material was highly dependent on the surface characteristics such as: topography, microstructure or mechanical properties. The controlled cellular response was achieved by modifying the surface to obtain a network of wells or channels of different dimensions via the laser interference lithography. This technique determined a high resolution shape, size and distribution patterns. As a result, it was possible to control cells in the scale corresponding to biological processes. The surface periodization ensured the optimal flow of oxygen and nutrients within the biomaterial, which was of a key importance for the cell adhesion and proliferation. The work attempted at producing the surface networks mimicking natural blood vessels. To stimulate the formation of new blood vessel the finishing resorbable synthetic coatings were applied on the surface to act as a drug carrier. Therefore, the initial trial to introduce factors stimulating the blood vessels growth was performed.

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Carbon-based coatings on titanium substrate, laser modifed to control endothelium cell growth

Trembecka-Wójciga Klaudia, Major Roman, Ostrowski Roman, Surmiak Marcin, Lackner Jurgen

Engineering of Biomaterials

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2020

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Vol. 23, no. 158 spec. iss.

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