Yazar "BAYRAK, Özgü" seçeneğine göre listele

Listeleniyor 1 - 2 / 2
  • Küçük Resim
    Öğe
    The effect of boron amount in the electrolyte on the corrosion properties of Ti45Nb coated by PEO
    (2023) VANGÖLÜ, S. Yenal; BAYRAK, Özgü
    Developing more biocompatible biomaterials with mechanical properties similar to those of cortical bone has long been a challenge for scientists. They are still working on new alloys and coating processes to meet this challenge. Among these biocompatible materials, ß-titanium alloys, which will prevent stress-shielding and have a Poisson’s ratio very close to the cortical bone, have been attracting the attention of scientists for a long time. In addition to this, the PEO method, which makes it possible to embed ions into the oxide layer, has also come to the fore in recent years as a surface treatment in order to increase the corrosion resistance, wear resistance and biocompatibility of biomaterials and also to provide antibacterial/antimicrobial properties. In this study, Ca and P-containing oxide layers with two different boron content and no boron content were successfully formed on Ti45Nb ß-titanium alloy substrate by using the PEO method. Surface characterization and corrosion resistance tests of these layers were carried out. The obtained results were compared with each other and with the uncoated substrate. XRD analysis showed that the coatings are primarily composed of two major polymorphs of TiO2, anatase and rutile. Static electrochemical measurements were made in diluted Foetal Bovine Serum (FBS) and hydrogen peroxide added serum. H2O2 was added to simulate the inflammatory state in the body. The measurements showed that all the coated samples had lower corrosion current densities compared to the uncoated ones both in serum and H2O2-added serum.
  • Küçük Resim
    Öğe
    Finite element simulation of femoral stems lightweighted with re-entrant honeycomb lattice structure
    (2023) BAYRAK, Özgü
    Artificial hip joints are used to replace damaged or diseased natural joints. When the stress that is typically applied to the bone changes because the implant and bone are different in stiffness, a phenomenon known as stress shielding occurs. Stress shielding can lead to bone weakening through reduced density and aseptic loosening in the long term. Studies are ongoing to overcome this phenomenon through geometric design, the use of materials with a low modulus of elasticity, or latticed implants. In this study, the effect of lightening the hip prosthesis with lattice structures on stress shielding is investigated using finite element simulation. The femoral stem of a solid hip prosthesis was lightweighted, with a re-entrant honeycomb auxetic cellular lattice structure, and structural analysis was performed. Two different lattice orientations were used, and it was observed that the stress distribution was more homogeneous in both orientations. In these femoral stems, which can be easily produced using additive manufacturing methods, a volume reduction of up to 16% was achieved. The stress transmitted to the bone increased by more than 36%, depending on the orientation, which is a promising result for reducing the stress shield effect.