Hybrid coatings for orthopaedic implants formed by physical vapour deposition and microarc oxidation

This study is focused on the preparation of new hybrid layers intended for surface modification of Ti-6Al-4V alloys for potential orthopaedic and dental applications. Combination of the technology of physical vapour deposition (PVD) and subsequent micro-arc oxidation (MAO) was utilized for the deposition of Ti and ZrTi to form hybrid oxide layers. The oxide layers were prepared using an alkaline electrolyte with glycerol as an additive under micro-arc discharge conditions with different Si content on their surfaces. The hybrid ZrTi coatings with a Zr/Si structure achieved the best tribological properties described by a low friction coefficient of 0.3 and high abrasion resistance. There was also an increase in corrosion potential and polarization resistance of hybrid ZrTi coatings. Although the proliferation of human bone marrow mesenchymal stem cells was slower on these hydrophilic Ti and ZrTi coatings than both on uncoated Ti-6Al-4V and the reference tissue culture polystyrene dishes, both types of hybrid coating promoted greater osteogenic differentiation of these cells, indicated by approx. twice as high activity of alkaline phosphatase. The hybrid oxide layers newly developed in this study - especially the layers with Zr - are therefore promising for coating metallic bone implants.Web of Science219art. no. 11081

The effect of long-term operation on the transition temperature FATT of tubes made of 15 128.5 steel

Import 05/08/2014Předložená bakalářská práce se zabývá využitím penetračních testů pro stanovení tranzitní teploty FATT. Jejím cílem je stanovení teploty FATT z výsledků standardizovaných zkoušek rázem v ohybu a stanovení tranzitní teploty penetračního testu Tsp u materiálu neprovozované trubky ø 457 x 28 mm a materiálu výstupní komory mezi-přehříváku ø 521 x 36 mm exponované po dobu 90 000 hodin na teplotě 540°C vyrobených z oceli 14MoV6-3.This bachelor thesis deals with the use of penetration testing to determine the transition temperature FATT. Its aim is to determine the temperature FATT of the results of standardized tests, impact bending and determination of transition temperature Tsp penetration test material in the non-operating pipe ø 457 x 28 mm and a material outlet chamber between the superheater-ø 521 x 36 mm exposed for 90,000 hours at a temperature of 540 °C made from steel 14MoV6-3.636 - Katedra materiálového inženýrstvívelmi dobř

The effect of „U“ notch on the evaluation of FATT temperature from the results od Small Punch tests.

Import 02/11/2016Předložená diplomová práce se zabývá vlivem vrubovaných penetračních disků na tranzitní teplotu penetračních testů TSP, která je používána pro stanovení teploty FATT z výsledků penetračních testů. Experimentální část práce byla realizována na materiálu neprovozované trubky ø 219,1 x 22,2 mm z oceli P92.The present thesis deals with the influence of penetration notched discs on transit temperature penetration tests TSP, which is used to determine the temperature FATT of the results of penetration tests. The experimental part of the work was carried out on the material out of operation pipes ø 219.1 x 22.2 mm of steel P92.636 - Katedra materiálového inženýrstvívelmi dobř

3D printed hollow off-axis profiles based on carbon fiber-reinforced polymers: Mechanical testing and finite element method analysis

The aim of the paper is to design, manufacture, and test an off-axis composite profile of circular cross-section. Composite profile based on continuous carbon fibers reinforcing the onyx matrix, i.e., a matrix that consists of nylon and micro carbon fibers, was produced by fused deposition modeling (FDM) method. A buckling test of the six printed composite specimens was performed on a tensile test machine. The values of the experiment were compared with the values of the computational simulation using the Finite Element Method (FEM) analysis. The mean value of the experimentally determined critical force at which the composite profile failed was 3102 N, while the value of the critical force by FEM analysis was calculated to be 2879 N. Thus, reliability of the simulation to determine the critical force differed from the experimental procedure by only 7%. FEM analysis revealed that the primary failure of 3D printed composite parts was not due to loss of stability, but due to material failure. With great accuracy, the results of the comparison show that it is possible to predict the mechanical properties of 3D printed composite laminates on the basis of a theoretical model.Web of Science1317art. no. 294