Publications by authors named "K Sztwiertnia"

High plasticity of bioabsorbable stents, either cardiac or ureteral, is of great importance in terms of implants' fabrication and positioning. Zn-Cu constitutes a promising group of materials in terms of feasible deformation since the superplastic effect has been observed in them, yet its origin remains poorly understood. Therefore, it is crucial to inspect the microstructural evolution of processed material to gain an insight into the mechanisms leading to such an extraordinary property.

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The phenomenon of superior biological behavior observed in titanium processed by an unconventional severe plastic deformation method, that is, hydrostatic extrusion, has been described within the present study. In doing so, specimens varying significantly in the crystallographic orientation of grains, yet exhibiting comparable grain refinement, were meticulously investigated. The aim was to find the clear origin of enhanced biocompatibility of titanium-based materials, having microstructures scaled down to the submicron range.

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The study is concerned with the mechanical properties of Zn and three Zn-Mg double alloys with Mg concentrations: 0.5%, 1.0% and 1.

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The mechanical properties such as compressive strength and nanohardness were investigated for mollusk shells. The compressive strength was evaluated through a uniaxial static compression test performed along the load directions parallel and perpendicular to the shell axis, respectively, while the hardness and Young modulus were measured using nanoindentation. In order to observe the crack propagation, for the first time for such material, the in-situ X-ray microscopy (nano-XCT) imaging (together with 3D reconstruction based on the acquired images) during the indentation tests was performed.

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Specific crystallographic correlations between neighbouring grains in composites were established by the use of selected area electron diffraction in the transmission electron microscope. However, it was the development of orientation mapping techniques that made it possible to obtain a quantitative description of the distribution of boundaries between the grains of both the same phase and different phases. This study shows that orientation topography measurements made by electron backscatter diffraction in the scanning electron microscope allowed determination of the crystallographic relationships between grains of different phases.

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