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Open Access
Abstract: Synchrotron-based engineering science covers a large field of applications. However, they are all connected in two ways. First, the very synchrotron techniques employed to study the various applications all work in the same way in that they determine structural parameters on the atomic and microscopic scale. Secondly, the portfolio of applications discussed here describes the complete life cycle of an engineering material, starting with processing of the base material—often from the melt—then the characterization of material properties, followed by the forming and joining into components, then component characterization during service, material aging, damage and failure and, finally, recycling or decommissioning. The structural problems which occur during the different stages in the life cycle of a material are complex, due to the advanced material technology of today's devices. We have created alloys for special applications, compound materials with novel properties, sophisticated bulk and surface treatments, and new forming and joining techniques. We are also concerned with the effect of the material on the environment after it has ended its service.
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May 2017
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I12-JEEP: Joint Engineering, Environmental and Processing
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Donal P.
Finegan
,
Eric
Darcy
,
Matthew
Keyser
,
Bernhard
Tjaden
,
Thomas M. M.
Heenan
,
Rhodri
Jervis
,
Josh J.
Bailey
,
Romeo
Malik
,
Nghia T.
Vo
,
Oxana V.
Magdysyuk
,
Robert
Atwood
,
Michael
Drakopoulos
,
Marco
Dimichiel
,
Alexander
Rack
,
Gareth
Hinds
,
Dan J. L.
Brett
,
Paul R.
Shearing
Diamond Proposal Number(s):
[13884]
Open Access
Abstract: Lithium-ion batteries are being used in increasingly demanding applications where safety and reliability are of utmost importance. Thermal runaway presents the greatest safety hazard, and needs to be fully understood in order to progress towards safer cell and battery designs. Here, we demonstrate the application of an internal short circuiting device for controlled, on-demand, initiation of thermal runaway. Through its use, the location and timing of thermal runaway initiation is pre-determined, allowing analysis of the nucleation and propagation of failure within 18[thin space (1/6-em)]650 cells through the use of high-speed X-ray imaging at 2000 frames per second. The cause of unfavourable occurrences such as sidewall rupture, cell bursting, and cell-to-cell propagation within modules is elucidated, and steps towards improved safety of 18[thin space (1/6-em)]650 cells and batteries are discussed.
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Mar 2017
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[12163]
Open Access
Abstract: High energy X-ray diffraction (HEXRD) was used to characterize the amorphous structure of the as-prepared binary Ca61Al39 (at.%) metallic glass and its evolution during thermal loading. The investigation was performed in both reciprocal and real space by means of the first diffuse peak (FDP) analysis and the reduced atomic pair distribution function (PDF) analysis, respectively. It was found that bond lengths of the atomic CaeCa and CaeAl pairs of the as-prepared structure were 3.70 Å and 3.24 Å, respectively.
The coordination number of the first coordination shell was estimated to be 11.9. The analysis of the FDP
behaviour during thermal treatment proposed the existence of the elaxation temperature Tr at 150 °C.
Analysis of summations of all absolute differences between two consecutive intensity curves in the region of the FDP as a function of temperature revealed two crystallization temperatures at 280 °C and
305 °C. Products of a devitrification process were identified to be alike a triclinic Ca8Al13 and monoclinic
Ca13Al14 phase.
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Dec 2016
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I12-JEEP: Joint Engineering, Environmental and Processing
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Open Access
Abstract: The short pulse duration, small effective source size and high flux of synchrotron radiation is ideally suited for probing a wide range of transient deformation processes in materials under extreme conditions. In this paper, the challenges of high-resolution time-resolved indirect X-ray detection are reviewed in the context of dynamic synchrotron experiments. In particular, the discussion is targeted at two-dimensional integrating detector methods, such as those focused on dynamic radiography and diffraction experiments. The response of a scintillator to periodic synchrotron X-ray excitation is modelled and validated against experimental data collected at the Diamond Light Source (DLS) and European Synchrotron Radiation Facility (ESRF). An upper bound on the dynamic range accessible in a time-resolved experiment for a given bunch separation is calculated for a range of scintillators. New bunch structures are suggested for DLS and ESRF using the highest-performing commercially available crystal LYSO:Ce, allowing time-resolved experiments with an interframe time of 189 ns and a maximum dynamic range of 98 (6.6 bits).
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May 2016
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[9244]
Open Access
Abstract: Spiders are an important animal group, with a long history. Details of their origins remain limited, with little knowledge of their stem group, and no insights into the sequence of character acquisition during spider evolution. We describe a new fossil arachnid, Idmonarachne brasieri gen. et sp. nov. from the Late Carboniferous (Stephanian, ca 305–299 Ma) of Montceau-les-Mines, France. It is three-dimensionally preserved within a siderite concretion, allowing both laboratory- and synchrotron-based phase-contrast computed tomography reconstruction. The latter is a first for siderite-hosted fossils and has allowed us to investigate fine anatomical details. Although distinctly spider-like in habitus, this remarkable fossil lacks a key diagnostic character of Araneae: spinnerets on the underside of the opisthosoma. It also lacks a flagelliform telson found in the recently recognized, spider-related, Devonian–Permian Uraraneida. Cladistic analysis resolves our new fossil as sister group to the spiders: the spider stem-group comprises the uraraneids and I. brasieri. While we are unable to demonstrate the presence of spigots in this fossil, the recovered phylogeny suggests the earliest character to evolve on the spider stem-group is the secretion of silk. This would have been followed by the loss of a flagelliform telson, and then the ability to spin silk using spinnerets. This last innovation defines the true spiders, significantly post-dates the origins of silk, and may be a key to the group's success. The Montceau-les-Mines locality has previously yielded a mesothele spider (with spinnerets). Evidently, Late Palaeozoic spiders lived alongside Palaeozoic arachnid grades which approached the spider condition, but did not express the full suite of crown-group autapomorphies.
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Mar 2016
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I12-JEEP: Joint Engineering, Environmental and Processing
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Open Access
Abstract: Distortion correction or camera calibration for an imaging system
which is highly configurable and requires frequent disassembly for
maintenance or replacement of parts needs a speedy method for
recalibration. Here we present direct techniques for calculating distortion
parameters of a non-linear model based on the correct determination of the
center of distortion. These techniques are fast, very easy to implement, and
accurate at sub-pixel level. The implementation at the X-ray tomography
system of the I12 beamline, Diamond Light Source, which strictly requires
sub-pixel accuracy, shows excellent performance in the calibration image
and in the reconstructed images.
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Dec 2015
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[7338]
Abstract: To improve the manufacturing quality of welded structures, to prevent failures at weld joints and to predict their lifetime, measurements of the residual stresses generated by welding in the structures are extremely useful. The residual stresses may reduce the component life due to phenomena that occur at low applied stresses such as brittle fracture, fatigue and stress corrosion cracking. Welded thin Ti–6Al–4V panel components are commonly found in aero-engine assemblies and the weld integrity and reliability are critical. In this work, the residual stress distributions in a welded thin Ti–6Al–4V T-joint were measured by the newly developed SScanSS program with synchrotron X-ray diffraction technique. The measurement performed in this study, which included a large number of measurement points, has mapped a complete stress field in a thin sheet T-joint weld. It has not only provided improved understanding of residual stress in such a joint but also filled the missing link between the residual stress obtained by numerical modelling and their validation. The results have shown that the longitudinal stresses play the most important role in the residual stress distribution over the flange and high tensile stresses appear in the region near the weld zone. The measured results were compared with the numerically predicted results and these showed good agreement.
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Oct 2015
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I12-JEEP: Joint Engineering, Environmental and Processing
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Abstract: During solidification of metallic alloys, coalescence leads to the formation of solid bridges between grains or grain clusters when both solid and liquid phases are percolated. As such, it represents a key transition with respect to the mechanical behavior of solidifying alloys and to the prediction of solidification cracking. Coalescence starts at the coherency point when the grains begin to touch each other, but are unable to sustain any tensile loads. It ends up at mechanical coherency when the solid phase is sufficiently coalesced to transmit macroscopic tensile strains and stresses. Temperature at mechanical coherency is a major input parameter in numerical modeling of solidification processes as it defines the point at which thermally induced deformations start to generate internal stresses in a casting. This temperature has been determined for Al-Zn alloys using in situ X-ray diffraction during casting in a dog-bone-shaped mold. This setup allows the sample to build up internal stress naturally as its contraction is prevented. The cooling on both extremities of the mold induces a hot spot at the middle of the sample which is irradiated by X-ray. Diffraction patterns were recorded every 0.5 seconds using a detector covering a 426 × 426 mm2 area. The change of diffraction angles allowed measuring the general decrease of the lattice parameter of the fcc aluminum phase. At high solid volume fraction, a succession of strain/stress build up and release is explained by the formation of hot tears. Mechanical coherency temperatures, 829 K to 866 K (556 °C to 593 °C), and solid volume fractions, ca. 98 pct, are shown to depend on solidification time for grain refined Al-6.2 wt pct Zn alloys.
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Sep 2015
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I12-JEEP: Joint Engineering, Environmental and Processing
I13-2-Diamond Manchester Imaging
I18-Microfocus Spectroscopy
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Open Access
Abstract: Tomographic datasets collected at synchrotrons are becoming very large and complex, and, therefore, need to be managed efficiently. Raw images may have high pixel counts, and each pixel can be multidimensional and associated with additional data such as those derived from spectroscopy. In time-resolved studies, hundreds of tomographic datasets can be collected in sequence, yielding terabytes of data. Users of tomographic beamlines are drawn from various scientific disciplines, and many are keen to use tomographic reconstruction software that does not require a deep understanding of reconstruction principles. We have developed Savu, a reconstruction pipeline that enables users to rapidly reconstruct data to consistently create high-quality results. Savu is designed to work in an 'orthogonal' fashion, meaning that data can be converted between projection and sinogram space throughout the processing workflow as required. The Savu pipeline is modular and allows processing strategies to be optimized for users' purposes. In addition to the reconstruction algorithms themselves, it can include modules for identification of experimental problems, artefact correction, general image processing and data quality assessment. Savu is open source, open licensed and 'facility-independent': it can run on standard cluster infrastructure at any institution.
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May 2015
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I12-JEEP: Joint Engineering, Environmental and Processing
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Michael
Drakopoulos
,
Thomas
Connolley
,
Christina
Reinhard
,
Robert
Atwood
,
Oxana
Magdysyuk
,
Nghia
Vo
,
Mike
Hart
,
Leigh
Connor
,
Bob
Humphreys
,
George
Howell
,
Steve
Davies
,
Tim
Hill
,
Guy
Wilkin
,
Ulrik
Pedersen
,
Andrew
Foster
,
Nicoletta
De Maio
,
Mark
Basham
,
Fajin
Yuan
,
Kaz
Wanelik
Open Access
Abstract: I12 is the Joint Engineering, Environmental and Processing (JEEP) beamline,
constructed during Phase II of the Diamond Light Source. I12 is located on
a short (5 m) straight section of the Diamond storage ring and uses a 4.2 T
superconducting wiggler to provide polychromatic and monochromatic X-rays
in the energy range 50150 keV. The beam energy enables good penetration
through large or dense samples, combined with a large beam size (1 mrad
horizontally x 0.3 mrad vertically). The beam characteristics permit the study of
materials and processes inside environmental chambers without unacceptable
attenuation of the beam and without the need to use sample sizes which are
atypically small for the process under study. X-ray techniques available to users
are radiography, tomography, energy-dispersive diffraction, monochromatic
and white-beam two-dimensional diffraction/scattering and small-angle X-ray
scattering. Since commencing operations in November 2009, I12 has established
a broad user community in materials science and processing, chemical
processing, biomedical engineering, civil engineering, environmental science,
palaeontology and physics.
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May 2015
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