I13-2-Diamond Manchester Imaging
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Dominic L. R.
Melvin
,
Marco
Siniscalchi
,
Dominic
Spencer-Jolly
,
Bingkun
Hu
,
Ziyang
Ning
,
Shengming
Zhang
,
Junfu
Bu
,
Shashidhara
Marathe
,
Anne
Bonnin
,
Johannes
Ihli
,
Gregory J.
Rees
,
Patrick S.
Grant
,
Charles W.
Monroe
,
T. James
Marrow
,
Guanchen
Li
,
Peter G.
Bruce
Diamond Proposal Number(s):
[30683]
Open Access
Abstract: Avoiding lithium dendrites at the lithium/ceramic electrolyte interface and, as a result, avoiding cell short circuit when plating at practical current densities remains a significant challenge for all-solid-state batteries. Typically, values are limited to around 1 mA cm−2, even, for example, for garnets with a relative density of >99%. It is not obvious that simply densifying ceramic electrolytes will deliver high plating currents. Here we show that plating currents of 9 mA cm−2 can be achieved without dendrite formation, by densifying argyrodite, Li6PS5Cl, to 99%. Changes in the microstructure of Li6PS5Cl on densification from 83 to 99% were determined by focused ion beam-scanning electron microscopy tomography and used to calculate their effect on the critical current density (CCD). Modelling shows that not all changes in microstructure with densification act to increase CCD. Whereas smaller pores and shorter cracks increase CCD, lower pore population and narrower cracks act to decrease CCD. Calculations show that the former changes dominate over the latter, predicating an overall increase in CCD, as observed experimentally.
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Sep 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Jiaxu
Zuo
,
Kutsi
Akcicek
,
Shivansh
Nauriyal
,
Barrie
Dams
,
Stefan
Michalik
,
Thomas
Zillhardt
,
Martin
Ansell
,
Richard
Ball
,
Genoveva
Burca
,
Brian
Sheil
,
James
Marrow
,
Sinan
Acikgoz
Open Access
Abstract: Fibrous plaster (FP) ceilings, prevalent in late 19th- and early 20th-century UK theatres, are suspended using ‘wads’. Wads are hangers made of Plaster of Paris, reinforced with twisted woven jute fabric. Several recent collapses in historic fibrous plaster ceilings have been attributed to tensile failures in wads. To understand the failure mechanisms involved, tensile tests were performed on laboratory-produced wad-like samples at the I12 beamline of the UK Diamond Light Source. The tested samples were designed with a dog bone shape and mounted with clevis-grips at each end, to ensure controlled failures along the gauge length. The beamline offered the opportunity to conduct simultaneous synchrotron X-ray computed tomography (sCT) and diffraction measurements during loading, enabling the monitoring of internal crack formation and strain propagation at the microstructural scale. Simultaneously, acoustic emission (AE) and digital image correlation (DIC) measurements were conducted. Preliminary results from these datasets are discussed in this paper. The datasets will provide useful information to validate the ongoing development of algorithms which can categorise the internal failure mechanisms and damage state of wads using only AE signals.
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Sep 2024
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I12-JEEP: Joint Engineering, Environmental and Processing
I13-2-Diamond Manchester Imaging
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Bingkun
Hu
,
Shengming
Zhang
,
Ziyang
Ning
,
Dominic
Spencer-Jolly
,
Dominic L. R.
Melvin
,
Xiangwen
Gao
,
Johann
Perera
,
Shengda D.
Pu
,
Gregory J.
Rees
,
Longlong
Wang
,
Lechen
Yang
,
Hui
Gao
,
Shashidhara
Marathe
,
Genoveva
Burca
,
T. James
Marrow
,
Peter G.
Bruce
Diamond Proposal Number(s):
[26060, 30683, 28773]
Open Access
Abstract: Charging current densities of solid-state batteries with lithium metal anodes and ceramic electrolytes are severely limited due to lithium dendrites that penetrate the electrolyte leading to a short circuit. We show that dendrite growth can be inhibited by different crack deflection mechanisms when multi-layered solid electrolytes, such as Li6PS5Cl/Li3ScCl6/Li6PS5Cl and Li6PS5Cl/Li10GeP2S12/Li6PS5Cl, are employed but not when the inner layer is Li3PS4. X-ray tomographic imaging shows crack deflection along mechanically weak interfaces between solid electrolytes as a result of local mismatches in elastic moduli. Cracks are also deflected laterally within Li3ScCl6, which contains preferentially oriented particles. Deflection occurs without lithium being present. In cases where the inner layers react with lithium, the resulting decomposition products can fill and block crack propagation. All three mechanisms are effective at low stack pressures. Operating at 2.5 MPa, multi-layered solid electrolytes Li6PS5Cl/Li3ScCl6/Li6PS5Cl and Li6PS5Cl/Li10GeP2S12/Li6PS5Cl can achieve lithium plating at current densities exceeding 15 mA cm−2.
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Jul 2024
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Open Access
Abstract: The capacity of polygranular graphite to accommodate strain is important to its use within structural components. This study has used in situ neutron and synchrotron X-ray experiments to demonstrate that reorientation of crystal domains accompanies the accommodation of applied mechanical strain in unirradiated Gilsocarbon (GCMB/IM24) graphite. Orientation changes were observed using 3D X-ray Diffraction, and local changes in neutron scattering were also observed with energy-resolved Bragg-edge neutron imaging. In both cases, this behaviour at the crystal level was partially recovered when the load was removed. This study provides new evidence for crystal deformation mechanisms that contribute to polycrystalline graphite's elastic non-linearity and the development of permanent set, which may also explain the effects of fast neutron irradiation on graphite elastic behaviour.
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Aug 2023
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I13-2-Diamond Manchester Imaging
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Ziyang
Ning
,
Guanchen
Li
,
Dominic L. R.
Melvin
,
Yang
Chen
,
Junfu
Bu
,
Dominic
Spencer-Jolly
,
Junliang
Liu
,
Bingkun
Hu
,
Xiangwen
Gao
,
Johann
Perera
,
Chen
Gong
,
Shengda D.
Pu
,
Shengming
Zhang
,
Boyang
Liu
,
Gareth O.
Hartley
,
Andrew J.
Bodey
,
Richard I.
Todd
,
Patrick S.
Grant
,
David E. J.
Armstrong
,
T. James
Marrow
,
Charles W.
Monroe
,
Peter G.
Bruce
Diamond Proposal Number(s):
[23980]
Abstract: All-solid-state batteries with a Li anode and ceramic electrolyte have the potential to deliver a step change in performance compared with today’s Li-ion batteries1,2. However, Li dendrites (filaments) form on charging at practical rates and penetrate the ceramic electrolyte, leading to short circuit and cell failure3,4. Previous models of dendrite penetration have generally focused on a single process for dendrite initiation and propagation, with Li driving the crack at its tip5,6,7,8,9. Here we show that initiation and propagation are separate processes. Initiation arises from Li deposition into subsurface pores, by means of microcracks that connect the pores to the surface. Once filled, further charging builds pressure in the pores owing to the slow extrusion of Li (viscoplastic flow) back to the surface, leading to cracking. By contrast, dendrite propagation occurs by wedge opening, with Li driving the dry crack from the rear, not the tip. Whereas initiation is determined by the local (microscopic) fracture strength at the grain boundaries, the pore size, pore population density and current density, propagation depends on the (macroscopic) fracture toughness of the ceramic, the length of the Li dendrite (filament) that partially occupies the dry crack, current density, stack pressure and the charge capacity accessed during each cycle. Lower stack pressures suppress propagation, markedly extending the number of cycles before short circuit in cells in which dendrites have initiated.
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Jun 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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A.
Koko
,
S.
Singh
,
S.
Barhli
,
T.
Connolley
,
N. T.
Vo
,
T.
Wigger
,
D.
Liu
,
Y.
Fu
,
J.
Réthoré
,
J.
Lechambre
,
J.-Y.
Buffiere
,
T. J.
Marrow
Diamond Proposal Number(s):
[12585]
Open Access
Abstract: The propagation rate of a fatigue crack in a nodular cast iron, loaded in cyclic tension, has been studied in situ by X-ray computed tomography and digital volume correlation. The semi-elliptical crack initiated from an asymmetric corner notch and evolved to a semi-circular shape, initially with a higher growth rate towards one edge of the notch before the propagation rate along the crack front became essentially independent of po-sition. The phase congruency of the displacement field was used to measure the crack shape. The three-dimensional stress intensity factors were calculated via a linear elastic finite element model that used the displacement fields around the crack front as the boundary conditions. Closure of the crack tip region was observed. The cyclic change in the local mode I opening of the crack tip determined the local fatigue crack propaga-tion rate along the crack front.
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May 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[12585]
Open Access
Abstract: Background: Silicon carbide-fibre/silicon carbide matrix (SiC/SiC) composites are candidate materials for accident toler- ant fuel cladding in light water and advanced gas cooled nuclear fission reactors. The mechanical and damage behaviour of ceramic composites is sensitive to the composite geometry, the microstructure and the loading state. Reliable test methods are needed to investigate the subcritical damage that affects hermetic properties and strength, and this requires precise meas- urements under loading states that are representative of operating conditions.
Objective: The objective was a novel methodology to measure the deformation of an internally pressurised ceramic com- posite tube.
Methods: A burst test of an internally ground SiC/SiC (filament wound and braided) ceramic composite tube, pressurized by radial expansion of a compressed elastomer insert, was observed in situ by high resolution (synchrotron) X-ray tomography. The full field three-dimensional displacements were measured by digital volume correlation, with a precise rotation correc- tion applied to obtain the relative radial and circumferential displacements of the tube wall for the first time.
Results: The hoop strain, and its spatial variations, were determined as a function of the applied hoop stress and showed ovalisation and barreling of the tube. The quantity of subcritical matrix cracking increased with the tensile hoop strain, but the critical crack that caused rupture was not at the location of maximum tensile strain.
Conclusion: Precise measurements of the deformation during the burst test found non-uniform hoop strains that caused a non-uniform distribution of subcritical cracking, which could influence the hermetic properties and strength.
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Oct 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28314]
Abstract: Graphite and MAX Phase ceramics are materials under consideration as key core components in high temperature Gen IV reactors. Their structural integrity is dependent on the evolution of their material properties under elevated temperature and neutron irradiation, and also their performance under mechanical load at high temperatures. Test techniques are needed to measure the mechanical properties of small samples, which are suitable for irradiated materials. In this work, small ‘Brazilian’ discs (5 and 3 mm diameter) of the fine-grained graphite SNG742 and the MAX Phase ceramic Ti2AlC were tested in diametral compression up to 80% failure load, at ambient and elevated temperature, achieved by resistance heating, up to 950°C. The testing geometry produces a compressive-tensile biaxial stress state at the centre of the discs. Simultaneous synchrotron X-ray diffraction in transmission and digital image correlation of radiographs
enabled mapping of the elastic and bulk strains respectively at high spatial resolution within the specimens
The analysis aims to correlate these spatially to investigate the development of non-linear behaviour in
tension due to damage mechanisms, and their possible temperature dependent. Ultimately, this approach
will be applied to investigate the damage tolerance of neutron irradiated materials at elevated temperatures.
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Sep 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[27537]
Open Access
Abstract: In a simulated in-situ experiment annular contacts of 6082-T6 aluminium alloy were first exposed to various degrees of fretting wear, before synchrotron X-ray CT and diffraction were applied to examine the extent and development of wear damage. The wear volumes measured and development of the wear rate were consistent with the mathematical wear model of Fillot, Iordanoff & Berthier. Thickness and porosity of the worn zone were measured and the contact area between wearing elements estimated. Developments of residual strain and tribologically transformed structure were investigated through X-ray diffraction. This study demonstrates, for the first time, the value and viability of observing and quantifying wear through combination of X-ray CT and diffraction opening a path towards in-situ observations of wear.
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Jul 2022
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I12-JEEP: Joint Engineering, Environmental and Processing
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Ziyang
Ning
,
Dominic Spencer
Jolly
,
Guanchen
Li
,
Robin
De Meyere
,
Shengda D.
Pu
,
Yang
Chen
,
Jitti
Kasemchainan
,
Johannes
Ihli
,
Chen
Gong
,
Boyang
Liu
,
Dominic L. R.
Melvin
,
Anne
Bonnin
,
Oxana
Magdysyuk
,
Paul
Adamson
,
Gareth O.
Hartley
,
Charles W.
Monroe
,
James
Marrow
,
Peter G.
Bruce
Diamond Proposal Number(s):
[20795]
Abstract: Lithium dendrite (filament) propagation through ceramic electrolytes, leading to short circuits at high rates of charge, is one of the greatest barriers to realizing high-energy-density all-solid-state lithium-anode batteries. Utilizing in situ X-ray computed tomography coupled with spatially mapped X-ray diffraction, the propagation of cracks and the propagation of lithium dendrites through the solid electrolyte have been tracked in a Li/Li6PS5Cl/Li cell as a function of the charge passed. On plating, cracking initiates with spallation, conical ‘pothole’-like cracks that form in the ceramic electrolyte near the surface with the plated electrode. The spallations form predominantly at the lithium electrode edges where local fields are high. Transverse cracks then propagate from the spallations across the electrolyte from the plated to the stripped electrode. Lithium ingress drives the propagation of the spallation and transverse cracks by widening the crack from the rear; that is, the crack front propagates ahead of the Li. As a result, cracks traverse the entire electrolyte before the Li arrives at the other electrode, and therefore before a short circuit occurs.
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Apr 2021
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