Quantitative X-ray tomography

Maire, Éric; Withers, Philip J.

doi:10.1179/1743280413y.0000000023

Cited by 1,062 publications

(627 citation statements)

References 429 publications

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“…93 Focused ion beam-scanning electron microscope (FIB-SEM) slice and view tomography, 94 and X-ray computed tomography (X-ray CT) 95 are among the most prominent methods of reconstructing a sample in three dimensions. Even though the operation and image acquisition of both method is radically different, comparative studies showed, that acquired data is identical when the resolution is the same.…”

Section: Tortuosity Calculation In 3d Volumesmentioning

confidence: 99%

Tortuosity in electrochemical devices: a review of calculation approaches

Tjaden

Brett

Shearing

2016

International Materials Reviews

202

188

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The tortuosity of a structure plays a vital role in the transport of mass and charge in electrochemical devices. Concentration polarisation losses at high current densities are caused by mass transport limitations and are thus a function of microstructural characteristics. As tortuosity is notoriously difficult to ascertain, a wide and diverse range of methods has been developed to extract the tortuosity of a structure. These methods differ significantly in terms of calculation approach and data preparation techniques. Here, we review tortuosity calculation procedures applied in the field of electrochemical devices to better understand the resulting values presented in the literature. Visible differences between calculation methods are observed, especially when using porosity-tortuosity relationships and when comparing geometric and flux based tortuosity calculation approaches.

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Section: Tortuosity Calculation In 3d Volumesmentioning

confidence: 99%

Tortuosity in electrochemical devices: a review of calculation approaches

Tjaden

Brett

Shearing

2016

International Materials Reviews

202

188

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“…cubic cell and Voronoi structure, but they may not be able to sufficiently capture the actual structural effect of foam materials, since some factors such as cell-wall rate dependence and micro inertia depend on the actual structural characteristics [8]. This motivates the geometrically EPJ Web of Conferences realistic simulations based on cell structures obtained from computed tomography (CT) images (so-called imagebased modelling [9]), which has been employed to investigate the strain-rate sensitivity of open-cell foams [10,11] and the quasi-static compressive behaviour of closed-cell foams [12,13]. The dynamic behaviour of Alporas foam has yet to be examined in this way.…”

Section: Introductionmentioning

confidence: 99%

Strain-rate sensitivity of foam materials: A numerical study using 3D image-based finite element model

Sun

Withers

2015

EPJ Web of Conferences

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Abstract. Realistic simulations are increasingly demanded to clarify the dynamic behaviour of foam materials, because, on one hand, the significant variability (e.g. 20% scatter band) of foam properties and the lack of reliable dynamic test methods for foams bring particular difficulty to accurately evaluate the strain-rate sensitivity in experiments; while on the other hand numerical models based on idealised cell structures (e.g. Kelvin and Voronoi) may not be sufficiently representative to capture the actual structural effect. To overcome these limitations, the strain-rate sensitivity of the compressive and tensile properties of closed-cell aluminium Alporas foam is investigated in this study by means of meso-scale realistic finite element (FE) simulations. The FE modelling method based on X-ray computed tomography (CT) image is introduced first, as well as its applications to foam materials. Then the compression and tension of Alporas foam at a wide variety of applied nominal strain-rates are simulated using FE model constructed from the actual cell geometry obtained from the CT image. The stain-rate sensitivity of compressive strength (collapse stress) and tensile strength (0.2% offset yield point) are evaluated when considering different cell-wall material properties. The numerical results show that the rate dependence of cell-wall material is the main cause of the strain-rate hardening of the compressive and tensile strengths at low and intermediate strain-rates. When the strain-rate is sufficiently high, shock compression is initiated, which significantly enhances the stress at the loading end and has complicated effect on the stress at the supporting end. The plastic tensile wave effect is evident at high strain-rates, but shock tension cannot develop in Alporas foam due to the softening associated with single fracture process zone occurring in tensile response. In all cases the micro inertia of individual cell walls subjected to localised deformation is found to have negligible effect on the macro strain-rate sensitivity of Alporas foam.

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“…There are several tools available for 3D characterization e.g. X-ray computed Tomography (CT) [1], Serial Sectioning SEM Tomography (SST) [2,3], transmission electron microscopy [4] and Atom Probe [5]. Figure 1 demonstrates their complementarity in terms of the lengthscales they can access.…”

mentioning

confidence: 99%

“…However the limited volumes accessible through the Gallium Ion FIB present a severe limitation. The size of the volume that can be examined via SST and the depth from which the regions of interest identified by X-ray CT is also key to opening up possibilities through a correlative tomography framework [1]. There are many scenarios in materials science that require analysis across length-scales up to many 100's of microns that lie beyond what a Ga ion FIB can typically access, relating to grain microtextures, grain neighborhoods, grain boundaries, inclusions and cracks.…”

mentioning

confidence: 99%

Large volume 3D characterization by plasma FIB DualBeam microscopy

Burnett

Kelley²,

Winiarski

et al. 2015

Microsc Microanal

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There is a critical need to analyze many material systems in three dimensions (3D), for example to understand connectivity of phases, porous networks and complex shapes. There are several tools available for 3D characterization e.g. X-ray computed Tomography (CT) [1], Serial Sectioning SEM Tomography (SST) [2,3], transmission electron microscopy [4] and Atom Probe [5]. Figure 1 demonstrates their complementarity in terms of the lengthscales they can access. The emergence of dual beam Focused ion beam (FIB-SEM) using Gallium ions has provided a means of accessing regions of interest of 50 m dimensions both for site specific TEM and SST in the SEM with slice thicknesses down to 10 nm. Although destructive it has enables 3D imaging of structure, grain structure (via EBSD) and chemistry (by EDS). However the limited volumes accessible through the Gallium Ion FIB present a severe limitation. The size of the volume that can be examined via SST and the depth from which the regions of interest identified by X-ray CT is also key to opening up possibilities through a correlative tomography framework [1]. There are many scenarios in materials science that require analysis across length-scales up to many 100's of microns that lie beyond what a Ga ion FIB can typically access, relating to grain microtextures, grain neighborhoods, grain boundaries, inclusions and cracks. In this paper we present the first examination of the capabilities of a new type of FIB-SEM that utilizes a Xe Plasma beam FIB (PFIB) for machining alongside an electron imaging column. We show that the FEI Helios PFIB can achieve a throughput 20-50x that of a Ga ion FIB opening up regions 100s of microns beneath the surface and allowing serial section tomography over volumes of hundreds of micron dimensions. The performance of the PFIB is demonstrated through the study of an austenitic and a ferritic steel both used within the energy sector. The PFIB was operated at 30kV and 59 nA beam current to collect typically 100's of slices ~100 × 100 µm 2 cross section size and a slice thickness of 80 nm. In contrast to typical SST within a FIB a stage rocking mode (+/-5) is sued to minimize curtaining that may be created during unidirectional FIB milling. Images using the Through lens detector (TLD) were captures at high resolution with the pixel size < 40 nm. These SEM-PFIB settings allowed us to collect 10-20 slices per hour (Fig. 2). The study here focuses on a ferritic steel used in pressure vessels with the region analyzed e just below a ductile fracture surface (Fig. 3). The distribution of carbides, as well as the voids associated with the ductile fracture, were imaged and analyzed. Our results indicate that curtain-free surfaces with a high detail level of microstructural features, e.g. carbides at the sized at ~100 nm. Results shows that the PFIB SST technique produces low levels of surface damage as evidenced by good channeling contrast. We will also present results showing Kikuchi patterns from the machined surface.Other ongoing experimental studies acro...

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Quantitative X-ray tomography

Cited by 1,062 publications

References 429 publications

Tortuosity in electrochemical devices: a review of calculation approaches

Tortuosity in electrochemical devices: a review of calculation approaches

Strain-rate sensitivity of foam materials: A numerical study using 3D image-based finite element model

Large volume 3D characterization by plasma FIB DualBeam microscopy

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