Characterization of porosity and hollow defects in ceramic objects built by extrusion additive manufacturing

Čelko, Ladislav; Gutiérrez-Cano, Vanessa; Casas-Luna, Mariano; Matula, Jan; Oliver-Urrutia, Carolina; Remešová, Michaela; Dvořák, Karel; Zikmund, Tomáš; Kaiser, Jozef; Montúfar, Edgar B.

doi:10.1016/j.addma.2021.102272

Cited by 7 publications

(4 citation statements)

References 32 publications

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“…≠ c0), and the angles between a0, b0, and c0 are all 90° (α = β = γ = 90°). The theoretical density of Ba3.99Sm9.34Ti18O54 (i.e., 5.8948 g/cm 3 ) is larger than the density (i.e., 5.5385 g/cm 3 ) measured by gas displacement method, resulting in the relative density 5.5385/5.8948 = 94% owing to the porosity caused by the residual air when the sample was formed during preparation [86]. the mean size of the cuboid-like grains is 2.7 μm, which is about half of that (i.e., 5 indicating their greatest and weakest penetration resistance (or hardness), respectively.…”

Section: J U S T a C C E P T E Dmentioning

confidence: 79%

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Liu¹,

Xu²

2023

Journal of Advanced Ceramics

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Mechanical characterization of dielectric ceramics, which have drawn extensive attention in wireless communication, remains challenging. Micromechanical properties with microstructures of dielectric ceramic BaO-Sm2O3-5TiO2 (BST) were assessed by nanoindentation, microhardness, and microscratch tests under different indenters, along with X-ray diffraction, scanning electron microscopy, and Raman spectroscopy. Accurate determination of elastic modulus (i.e., 260 GPa) and indentation hardness (i.e., J u s t A c c e p t e d 16.2 GPa) of brittle BST ceramic by instrumented indentation technique requires low loads with little indentation-induced damage. Elastic modulus and indentation hardness were analyzed by different methodologies such as energybased and displacement-based approaches, and elastic recovery of Knoop imprint. Consistent values (about 3.1 MPa·m 1/2 ) of fracture toughness of BST ceramic were obtained by different methods such as Vickers indenter-induced cracking method, energy-based nanoindentation approaches, and linear elastic fracture mechanics-based scratch approach with a spherical indenter, demonstrating successful applications of indentation and scratch methods in characterizing fracture properties of brittle solids. The deterioration of elastic modulus or indentation hardness with the increase in indentation load is caused by indentation-induced damage, and can be used to determine fracture toughness of material by energy-based nanoindentation approaches, and the critical void volume fraction is 0.27 (or 0.18) if elastic modulus (or indentation hardness) of the brittle BST ceramic is used. The fracture work at the critical load corresponding to the initial decrease in elastic modulus or indentation hardness can also be used to assess fracture toughness of brittle solids, opening new venues of application of nanoindentation test as a means to characterize fracture toughness of brittle ceramics.

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Section: J U S T a C C E P T E Dmentioning

confidence: 79%

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Liu¹,

Xu²

2023

Journal of Advanced Ceramics

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“…Такие дефекты трудно обнаруживаемы при визуальном осмотре, но при этом они могут существенно снижать прочность конструкции [5][6][7][8]. Обеспечение качества изделий из ПКМ требует разработки современных методов и средств неразрушающего контроля [9][10][11].…”

Section: The Use Of X-ray Computed Tomography For the Diagnosis Of Co...unclassified

The use of X-Ray computed tomography for the diagnosis of composite structures in the energy sector

Krotova,

Sachenkov,

Mitryakin

et al. 2024

«Izvestiya vysshikh uchebnykh zavedenii. PROBLEMY ENERGETIKI»

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RELEVANCE In modern Russia, an important condition for the development of the Far North and Far Eastern regions is to provide these regions with electricity. In remote areas with increased wind potential, the use of wind power plants, the main structural elements of which are made of polymer composite materials (PCM), is promising. The most dangerous operational defect of the PCM is shock damage: due to hail strikes or pieces of ice that broke off during heating of the blades, as well as lightning strikes. Such defects, which are difficult to detect during visual inspection, can significantly reduce the strength and service life of the structure. At the stages of technology development and design certification, the use of modern methods of non-destructive testing is required.PURPOSE. To evaluate the possibilities of X-ray computed tomography for the diagnosis of structural elements made of PCM with impact damage.METHODS. After applying a low-speed impact to fragments of the blades of the wind turbine, a visual inspection and measurement of the size of internal injuries are carried out on a Phoenix V |Tome|X X-ray computed tomograph.RESULTS The nature of the damage inflicted with different impact energies on the most critical areas of fragments of the airfoil blades and the stringer panel is investigated. The depth and area of damage have been determined. The nature and size of internal injuries were studied using an X-rayCOMPUTED tomograph. conclusion. The results obtained allow us to estimate with high accuracy the size and location of impact damage, which can be used in strength calculations.

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“…Compared to traditional manufacturing, ceramic AM introduces additional types of defects (e.g., porosity specific to a certain printing process, extrusion-related defects, and air-trapped pores). 18,19 Defects tend to occur on a hierarchical basis, associated with the DIW process: inter-filament defects associated with the DIW tool path (where a filament is a single continuous stream of DIW-extruded material between changes in extrusion direction), intra-filament defects caused by binder removal; and grain size effects possibly due to particle size segregation in the feedstock, and there are also other defect modalities such as filament stacking. For example, because of the inverse relationship between print speed and voxel resolution, parts produced quickly and economically will necessarily contain larger extrusion-related defects and flaws compared to slower high-resolution processes.…”

Section: Build and Postprocessing: In Situ Control And Defectsmentioning

confidence: 99%

“…Like most other ceramic AM methods, DIW provides a porous “green” part that remains to be densified via binder burnout followed by sintering – the same steps that are involved in conventional ceramic processing. Compared to traditional manufacturing, ceramic AM introduces additional types of defects (e.g., porosity specific to a certain printing process, extrusion‐related defects, and air‐trapped pores) 18,19 . Defects tend to occur on a hierarchical basis, associated with the DIW process: inter‐filament defects associated with the DIW tool path (where a filament is a single continuous stream of DIW‐extruded material between changes in extrusion direction), intra‐filament defects caused by binder removal; and grain size effects possibly due to particle size segregation in the feedstock, and there are also other defect modalities such as filament stacking.…”

Section: Build and Postprocessing: In Situ Control And Defectsmentioning

confidence: 99%

Research, standards, and data needs for industrialization of ceramic direct ink writing

Allen

Levin

Maier

2022

Int J Ceramic Engine & Sci

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Here, we summarize a panel discussion on the direct ink writing (DIW) of ceramics, organized and moderated by the National Institute of Standards and Technology at the American Ceramic Society's 46th International Conference on Advanced Ceramics and Composites in January 2022. The panel reviewed the current state of the art in DIW, focusing on research directions, standards development, and data needs required to facilitate industrial adoption of these technologies. The panel agreed to form working groups for (1) exploring how the community can work together to develop and curate public databases of feedstock characteristics and properties of end-products and(2) organizing an international round-robin to compare performance properties of DIW-manufactured ceramics, potentially tied to ASTM/ISO standards development.

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Characterization of porosity and hollow defects in ceramic objects built by extrusion additive manufacturing

Cited by 7 publications

References 32 publications

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

The use of X-Ray computed tomography for the diagnosis of composite structures in the energy sector

Research, standards, and data needs for industrialization of ceramic direct ink writing

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Characterization of porosity and hollow defects in ceramic objects built by extrusion additive manufacturing

Cited by 7 publications

References 32 publications

Micromechanical characterization of microwave dielectric ceramic BaO–Sm 2O 3–5TiO 2 by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm 2O 3–5TiO 2 by indentation and scratch methods

The use of X-Ray computed tomography for the diagnosis of composite structures in the energy sector

Research, standards, and data needs for industrialization of ceramic direct ink writing

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Product

Resources

About

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods

Micromechanical characterization of microwave dielectric ceramic BaO–Sm ₂O ₃–5TiO ₂ by indentation and scratch methods