Micro porosity analysis in additive manufactured NiTi parts using micro computed tomography and electron microscopy

Khademzadeh, Saeed; Carmignato, Simone; Parvin, Nader; Zanini, Filippo; Bariani, Paolo Francesco

doi:10.1016/j.matdes.2015.10.161

Cited by 61 publications

(19 citation statements)

References 17 publications

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“…An advanced technology capable of overcoming the limitations of the above mentioned methods is X-ray CT, which enables non-destructive analyses of both external and internal features [16,17]. In particular, material porosity can be evaluated in terms of spatial distribution, size and morphology [14] and the fiber orientation can be successfully assessed from CT data throughout the entire part [18].…”

Section: X-ray Computed Tomographymentioning

confidence: 99%

Particle based method and X-ray computed tomography for pore-scale flow characterization in VRFB electrodes

Maggiolo

Zanini

Picano

et al. 2019

Energy Storage Materials

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Porous electrodes are pivotal components of Vanadium Redox Flow Batteries, which influence the power density, pressure drop losses, activation overpotentials, limit current density, bulk and contact resistance, and ohmic losses. The quantification of the fluid-mechanic efficiency of porous electrodes is a useful measure, as it is related to the mass transport losses and it affects the overall battery performances. Although several studies, both numerical and experimental, have been devoted to the electrode enhancement, most analyses are carried out under the simplifying assumption of linear, macrohomogeneous and isotropic behavior of the fluid mechanics in the porous material. We present an original approach built on the Lattice-Boltzmann Method and Lagrange Particle Tracking that makes use of pore-scale accurate geometrical data provided by X-ray computed tomography with the aim of studying the dispersion and reaction rates of liquid electrolyte reactants in the flow battery porous electrode. Following this methodology, we compare the fluid-dynamic performances provided by a commonly used carbon felt and an unconventional material, that is, a carbon vitrified foam. Surprisingly, results unveil the possibility of achieving higher fluid-mechanic efficiencies with the foam electrode, whose intrinsic microstructure promotes higher reaction rate.

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Section: X-ray Computed Tomographymentioning

confidence: 99%

Particle based method and X-ray computed tomography for pore-scale flow characterization in VRFB electrodes

Maggiolo

Zanini

Picano

et al. 2019

Energy Storage Materials

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“…Taking advantage of more accessible volumetric imaging devices, greatly increased computational power of modern computers and constantly refined imaging processing algorithms, digital volume correlation (DVC) [16][17][18] has experienced rapid growth in recent years and evolved into a powerful internal strain mapping technique. In combination with X-ray micro-computed tomography (micro-CT) imaging technique that allows to visualize internal micro-architectures of a specimen [19][20][21][22][23], DVC can provide data needed to characterize the mechanical behavior of materials in response to external loadings. Since the first application of DVC for strain mapping in bone tissue, subsequent DVC applications to various hard (e.g.…”

Section: Accepted Manuscriptmentioning

confidence: 99%

Morphological evolution and internal strain mapping of pomelo peel using X-ray computed tomography and digital volume correlation

2018

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“…In fact, 3D microstructure characterization is necessary to determine the shape of pores. Since pore size distribution and pore shapes in SLM are highly influenced by the energy input as well as the scanning strategy [7,8], CT can be an ideal analysis tool to determine process windows in terms of material density.…”

Section: Introductionmentioning

confidence: 99%

New aspects about the search for the most relevant parameters optimizing SLM materials

Mishurova

Artzt

Haubrich

et al. 2019

Additive Manufacturing

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While the volumetric energy density is commonly used to qualify a process parameter set, and to quantify its influence on the microstructure and performance of additively manufactured (AM) materials and components, it has been already shown that this description is by no means exhaustive. In this work, new aspects of the optimization of the selective laser melting process are investigated for AM Ti-6Al-4V. We focus on the amount of near-surface residual stress (RS), often blamed for the failure of components, and on the porosity characteristics (amount and spatial distribution). First, using synchrotron x-ray diffraction we show that higher RS in the subsurface region is generated if a lower energy density is used. However, we show that laser de-focusing and sample positioning inside the build chamber also play an eminent role, and we quantify this influence. In parallel, using X-ray Computed Tomography, we observe that porosity is mainly concentrated in the contour region, except in the case where the laser speed is small. The low values of porosity (less than 1%) do not influence RS.

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Micro porosity analysis in additive manufactured NiTi parts using micro computed tomography and electron microscopy

Cited by 61 publications

References 17 publications

Particle based method and X-ray computed tomography for pore-scale flow characterization in VRFB electrodes

Particle based method and X-ray computed tomography for pore-scale flow characterization in VRFB electrodes

Morphological evolution and internal strain mapping of pomelo peel using X-ray computed tomography and digital volume correlation

New aspects about the search for the most relevant parameters optimizing SLM materials

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