5 results on '"Douglas Fabris"'
Search Results
2. Multi-Scale Structuring of CoCrMo and AZ91D Magnesium Alloys Using Direct Laser Interference Patterning
- Author
-
Bruno Henriques, Douglas Fabris, Bogdan Voisiat, and Andrés Fabián Lasagni
- Subjects
direct laser interference patterning ,surface texturing ,multi-scale topography ,metallic alloys ,Mining engineering. Metallurgy ,TN1-997 - Abstract
In this work, the technique of Direct Laser Interference Patterning (DLIP) was used to fabricate micrometric structures at the surface of Cobalt-Chromium-Molybdenum and AZ91D magnesium alloys. Line-like patterns with spatial periods of 5 μm were textured using an ultra-short pulsed laser (10 ps pulse duration and 1064 nm wavelength) with a two-beam interference setup. The surface topography, morphology, and chemical modifications were analysed using Confocal Microscopy, Scanning Electron Microscopy, and Energy Dispersive Spectroscopy (EDS), respectively. Laser fluence and pulse overlap were varied to evaluate their influence on the final structure. Homogeneous structures were achieved for the CoCrMo alloy for every condition tested, with deeper structures (up to 0.85 μm) being achieved for higher energy levels (higher overlap and/or fluence). For high energy, sub-micrometric secondary structures, so-called LIPSS, could also be observed on the CoCrMo. The EDS analysis showed some oxidation after the laser texturing. Regarding the AZ91D alloy, deeper structures could be achieved (up to 2.5 μm), but more melting and oxidation was observed, forming spherical oxide particles. Nonetheless, these results bring new perspectives on the fabrication of microtextures on the surface of CoCrMo and AZ91D using DLIP.
- Published
- 2023
- Full Text
- View/download PDF
3. Direct Laser Interference Patterning of Bioceramics: A Short Review
- Author
-
Douglas Fabris, Andrés Fabián Lasagni, Márcio C. Fredel, and Bruno Henriques
- Subjects
laser ,direct laser interference patterning ,texturing ,bioceramics ,Technology ,Chemical technology ,TP1-1185 - Abstract
Bioceramics are a great alternative to use in implants due to their excellent biocompatibility and good mechanical properties. Depending on their composition, bioceramics can be classified into bioinert and bioactive, which relate to their interaction with the surrounding living tissue. Surface morphology also has great influence on the implant biological behavior. Controlled texturing can improve osseointegration and reduce biofilm formation. Among the techniques to produce nano- and micropatterns, laser texturing has shown promising results due to its excellent accuracy and reproducibility. In this work, the use of laser techniques to improve surface morphology of biomaterials is reviewed, focusing on the application of direct laser interference patterning (DLIP) technique in bioceramics.
- Published
- 2019
- Full Text
- View/download PDF
4. Multi-Scale Structuring of CoCrMo and AZ91D Magnesium Alloys Using Direct Laser Interference Patterning
- Author
-
Lasagni, Bruno Henriques, Douglas Fabris, Bogdan Voisiat, and Andrés Fabián
- Subjects
direct laser interference patterning ,surface texturing ,multi-scale topography ,metallic alloys - Abstract
In this work, the technique of Direct Laser Interference Patterning (DLIP) was used to fabricate micrometric structures at the surface of Cobalt-Chromium-Molybdenum and AZ91D magnesium alloys. Line-like patterns with spatial periods of 5 μm were textured using an ultra-short pulsed laser (10 ps pulse duration and 1064 nm wavelength) with a two-beam interference setup. The surface topography, morphology, and chemical modifications were analysed using Confocal Microscopy, Scanning Electron Microscopy, and Energy Dispersive Spectroscopy (EDS), respectively. Laser fluence and pulse overlap were varied to evaluate their influence on the final structure. Homogeneous structures were achieved for the CoCrMo alloy for every condition tested, with deeper structures (up to 0.85 μm) being achieved for higher energy levels (higher overlap and/or fluence). For high energy, sub-micrometric secondary structures, so-called LIPSS, could also be observed on the CoCrMo. The EDS analysis showed some oxidation after the laser texturing. Regarding the AZ91D alloy, deeper structures could be achieved (up to 2.5 μm), but more melting and oxidation was observed, forming spherical oxide particles. Nonetheless, these results bring new perspectives on the fabrication of microtextures on the surface of CoCrMo and AZ91D using DLIP.
- Published
- 2023
- Full Text
- View/download PDF
5. Influence of specimens’ geometry and materials on the thermal stresses in dental restorative materials during thermal cycling
- Author
-
Filipe Samuel Silva, Michael Gasik, Márcio Celso Fredel, Júlio C.M. Souza, Douglas Fabris, and Bruno Henriques
- Subjects
Ceramics ,Hot Temperature ,Time Factors ,Materials science ,medicine.medical_treatment ,Finite Element Analysis ,Metal Ceramic Alloys ,Geometry ,02 engineering and technology ,Temperature cycling ,Bending ,Crown (dentistry) ,Thermalcycling ,Stress (mechanics) ,Dental Materials ,03 medical and health sciences ,0302 clinical medicine ,Materials Testing ,medicine ,Cylinder ,Cubic zirconia ,Ceramic ,Composite material ,Dental Restoration, Permanent ,General Dentistry ,ta215 ,Mechanical Phenomena ,Crowns ,Dental Bonding ,030206 dentistry ,All-ceramic restorations ,021001 nanoscience & nanotechnology ,Dental Porcelain ,Finite element method ,visual_art ,Metal-ceramic restorations ,visual_art.visual_art_medium ,Thermal stresses ,Stress, Mechanical ,Zirconium ,Shear Strength ,0210 nano-technology - Abstract
Objectives Thermal cycling is widely used to simulate the aging of restorative materials corresponding to the changes of temperature in the oral cavity. However, test parameters present in literature vary considerably, which prevents comparison between different reports. The aim of this work is to assess the influence of the specimens’ geometry and materials on the thermal stresses developed during thermal cycling tests. Materials and methods Finite elements method was used to simulate the conditions of thermal cycling tests for three different sample geometries: a three-points bending test sample, a cylinder rod and more complex shape of a restoration crown. Two different restorative systems were considered: all-ceramic (zirconia coupled with porcelain) and metal-ceramic (CoCrMo alloy coupled with porcelain). The stress state of each sample was evaluated throughout the test cycle. Results The results show that the sample geometry has great influence on the stress state, with difference of up to 230% in the maximum stress between samples of the same composition. The location of maximum stress also changed from the interface between materials to the external wall. Conclusions Maximum absolute stress values were found to vary between 2 and 4 MPa, which might not be critical even for ceramics. During multi-cycle testing these stresses would cause different fatigue in various locations. The zirconia-based specimens and zirconia-based restoration (crown) exhibited the most similar stress states. Thus it might be recommended to use these geometries for fast screening of the materials for this type of restorations. Clinical significance The selection of specimens’ geometry and materials should be carefully considered when aging conditions close to clinical ones want to be simulated.
- Published
- 2017
Catalog
Discovery Service for Jio Institute Digital Library
For full access to our library's resources, please sign in.