Wyniki wyszukiwania - Biblioteka Nauki

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Experimental study of Fe-Ni-Ti-Cr system

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Hoppe V. , Gibas A. , Grzegorczyk W. , Małecki M. , Hasiak M.

Interdisciplinary Journal of Engineering Sciences

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2019

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tom Vol. 7, no. 1

1--14

EN

The research comprises a discussion about a formation of intermetallic phase with stoichiometric composition Fe2Ti, called Laves phase, and influence of chromium on the whole structure containing this phase by means of comparison of the two alloys. A base Fe35Ni35Ti30 alloy was used as a reference and then compared with a Fe-Ni-Ti chromium doped - Fe30Ni35Ti30Cr5 alloy. The study of microstructure performed with scanning electron microscope enabled to distinguish different phases. These regions are rich in mixture of Fe-Ni and Ti-Ni elements. The identified phases are Fe2Ti and Ni3Ti which was confirmed by X-ray diffraction and simultaneously it is consistent with energy dispersive spectroscopy results. Differential scanning calorimetry confirmed also multi-phase composition. As a result different hardness was measured for these phases using nanoindentation. The overall hardness was established using the Vickers method.

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The effect of geometry on mechanical properties of Ti6Al4V ELI scaffolds manufactured using additive manufacturing technology

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Szymczyk P. , Hoppe V. , Ziółkowski G. , Smolnicki M. , Madeja M.

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tom Vol. 20, no. 1

144--156

EN

Owing to the possibility of direct processing of CAD models into three-dimensional objects, additive manufacturing (AM) is widely used in the production of individualized bone scaffolds that can lead to perfect restoration of anatomical structures of missing bone tissues. In this work, one of the AM technologies was applied, referred to as Electron Beam Melting (EBM), using Ti6Al4V ELI alloy to produce open-cell structures. Scaffold architecture influences its mechanical properties and is important from the point of view of biological considerations. To optimize mechanical properties, designed geometries were subjected to Finite Element Method analysis and experimental static compression tests. Also, geometric CT analysis of manufactured scaffolds was carried out (geometry deviations up to ± 300 µm). Obtained results have shown that AM can be used to produce Ti6Al4V ELI alloy scaffolds displaying mechanical parameters similar to those of bone tissue (E = 0.45–2.88 MPa). The EBM process affects the microstructure and macrostructural properties of manufactured parts, e.g., through internal porosities present in the material by to unmelted powder particles (internal porosity in range of 1.25–2.25%). To assess the quality and suitability of additively manufactured implants, a multidimensional verification of the impact of the manufacturing process on the properties of the final product was performed.

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Investigation of porosity behavior in SLS polyamide-12 samples using ex-situ X-ray computed tomography

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Ziółkowski G. , Grochowska E. , Kęszycki D. , Gruber P. , Hoppe V. , Szymczyk-Ziółkowska P. , Kurzynowski T.

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tom Vol. 39, No. 3

436--445

EN

The paper presents a detailed description of the method of carrying out static tensile tests in ex-situ X-ray computed tomography (XCT) conditions. The study compares samples manufactured with the use of additive technology in two orientations, horizontally and vertically, which correspond to the in-layer and between-layer sintering mechanisms. Both the fracture mechanism and porosity behavior differed significantly for the two manufacturing directions. The conducted analysis made it possible to compare the changes in porosity, the number of pores, and also their diameters and shape before and after the tensile test. This allows for in-depth identification and better understanding of the phenomena occurring during the static tensile test of polyamide-12 samples manufactured using selective laser sintering (SLS) technology.

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Corrosion resistance characteristics of a Ti-6Al-4V ELI alloy fabricated by electron beam melting after the applied post-process treatment methods

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Szymczyk-Ziółkowska P. , Hoppe V. , Gąsiorek J. , Rusińska M. , Kęszycki D. , Szczepański Ł. , Dudek-Wicher R. , Detyna J.

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2021

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tom Vol. 41, no. 4

1575--1588

EN

Post-process modifications in the form of Hot Isostatic Pressing or surface treatment methods such as sandblasting ormachining have been widely used in the case of improving the quality of elements manufactured with the use of EBM (Electron Beam Melting). The corrosion resistance of titanium alloys for medical applications is a key and critical aspect for the use of personalized components as implants, especially when investigating the issue of additive manufacturing. This paper presents the results of research on the influence of HIP processing on the functional properties of the material produced with the use of EBM, considering the aspect of reconstructive medicine. Both the influence of surface modification and the influence of post-process treatment on microstructural, mechanical, and corrosion properties were investigated. A wide range of research has been carried out using scanning and transmission electron microscopy methods, in combination with three-point static bending tests and performing corrosion tests using potentiodynamic polarization and electrochemical spectroscopic impedance (EIS) in Hank‘s solution. The results showed that HIP treatment has a positive effect on the corrosive properties of the material in terms of increased corrosion resistance compared to materials not subjected to this type of post-process treatment. This fact is also related to the change of the alloy microstructure and the change of mechanical properties towards increased plasticity. In the case of the production of personalized implants with the use of EBM, it is worth considering the benefits of the HIP.