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20 results on '"Chioibasu, Diana"'

4. In Situ Fabrication of TiC/Ti–Matrix Composites by Laser Directed Energy Deposition.

Author

Mihai, Sabin, Baciu, Florin, Radu, Robert, Chioibasu, Diana, and Popescu, Andrei C.

Subjects
SOLUTION strengthening, MECHANICAL wear, TITANIUM carbide, LASER beams, LASER deposition, HYPEREUTECTIC alloys, TITANIUM composites
Abstract

In this study, crack-free TiC/Ti composites with TiC content ranging from 0 to 15 wt.% were successfully fabricated using Direct Energy Deposition with a dual-feeder system that concomitantly delivered different amounts of both constituents into a high-power laser beam. The samples were investigated to evaluate the morphologies and distribution behavior of TiC. The microhardness values of the samples obtained under optimal processing conditions increased from 192 ± 5.3 HV0.2 (pure Ti) to 300 ± 14.2 HV0.2 (Ti + wt.% 15 TiC). Also, TiC has a significant impact on the Ti matrix, increasing the strength of TMCs up to 725 ± 5.4 MPa, while the elongation drastically decreased to 0.62 ± 0.04%. The wear rate is not proportionally affected by the rise content of TiC reinforcement; the hypoeutectic region of TMCs exhibited a wear rate of 2.45 mm3/N·m (Ti + wt.% 3 TiC) and a friction coefficient of 0.48 compared to the ones from the hypereutectic region, which measured a wear rate of 3.02 mm3/N·m (Ti + wt.% 15 TiC) and a friction coefficient of 0.63. The improved values of mechanical properties in the case of TMCs as compared to pure Ti are provided due to the solid solution strengthening of carbon and the fine grain strengthening. This work outlines a method for changing TiC morphologies to improve the hardness and tensile strength of TMCs fabricated starting from micro-scale powder. [ABSTRACT FROM AUTHOR]

Published
2024
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17. Animal Origin Bioactive Hydroxyapatite Thin Films Synthesized by RF-Magnetron Sputtering on 3D Printed Cranial Implants

Author

Chioibasu, Diana, primary, Duta, Liviu, additional, Popescu-Pelin, Gianina, additional, Popa, Nicoleta, additional, Milodin, Nichita, additional, Iosub, Stefana, additional, Balescu, Liliana Marinela, additional, Catalin Galca, Aurelian, additional, Claudiu Popa, Adrian, additional, Oktar, Faik N., additional, Stan, George E., additional, and Popescu, Andrei C., additional

Published
2019
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19. Laser-direct writing by two-photon polymerization of 3D honeycomb-like structures for bone regeneration

Author

Paun, Irina Alexandra, primary, Popescu, Roxana Cristina, additional, Mustaciosu, Cosmin Catalin, additional, Zamfirescu, Marian, additional, Calin, Bogdan Stefanita, additional, Mihailescu, Mona, additional, Dinescu, Maria, additional, Popescu, Andrei, additional, Chioibasu, Diana, additional, Soproniy, Mihai, additional, and Luculescu, Catalin Romeo, additional

Published
2018
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20. In Vivo Assessment of Bone Enhancement in the Case of 3D-Printed Implants Functionalized with Lithium-Doped Biological-Derived Hydroxyapatite Coatings: A Preliminary Study on Rabbits

Author

Johny Neamtu, Oana A. Zureigat, Andrei C. Popescu, Faik N. Oktar, Diana Chioibasu, Liviu Duta, Razvan Melinte, Gianina Popescu-Pelin, Duta, Liviu, Neamtu, Johny, Melinte, Razvan P., Zureigat, Oana A., Popescu-Pelin, Gianina, Chioibasu, Diana, Oktar, Faik N., and Popescu, Andrei C.

Subjects
Fabrication, Materials science, Scanning electron microscope, chemistry.chemical_element, PORCINE BONE, 02 engineering and technology, METALLIC IMPLANTS, 010402 general chemistry, 01 natural sciences, food industrial by-products, Pulsed laser deposition, THIN-FILMS, In vivo, Ultimate tensile strength, Materials Chemistry, biological-derived hydroxyapatite coatings, DEPOSITION, pulsed laser deposition, in vivo extraction force, GENE-EXPRESSION, Extraction (chemistry), Titanium alloy, Surfaces and Interfaces, 3D printing, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Surfaces, Coatings and Films, DIFFERENTIATION, chemistry, lcsh:TA1-2040, Lithium, MAGNESIUM-ENRICHED HYDROXYAPATITE, 0210 nano-technology, lcsh:Engineering (General). Civil engineering (General), lithium doping, STEM-CELLS, Biomedical engineering
Abstract

We report on biological-derived hydroxyapatite (HA, of animal bone origin) doped with lithium carbonate (Li-C) and phosphate (Li-P) coatings synthesized by pulsed laser deposition (PLD) onto Ti6Al4V implants, fabricated by the additive manufacturing (AM) technique. After being previously validated by in vitro cytotoxicity tests, the Li-C and Li-P coatings synthesized onto 3D Ti implants were preliminarily investigated in vivo, by insertion into rabbits&rsquo, femoral condyles. The in vivo experimental model for testing the extraction force of 3D metallic implants was used for this study. After four and nine weeks of implantation, all structures were mechanically removed from bones, by tensile pull-out tests, and coatings&rsquo, surfaces were investigated by scanning electron microscopy. The inferred values of the extraction force corresponding to functionalized 3D implants were compared with controls. The obtained results demonstrated significant and highly significant improvement of functionalized implants&rsquo, attachment to bone (p-values &le, 0.05 and &le, 0.00001), with respect to controls. The correct placement and a good integration of all 3D-printed Ti implants into the surrounding bone was demonstrated by performing computed tomography scans. This is the first report in the dedicated literature on the in vivo assessment of Li-C and Li-P coatings synthesized by PLD onto Ti implants fabricated by the AM technique. Their improved mechanical characteristics, along with a low fabrication cost from natural, sustainable resources, should recommend lithium-doped biological-derived materials as viable substitutes of synthetic HA for the fabrication of a new generation of metallic implant coatings.

Published
2020

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