E02-JEM ARM 300CF
I15-1-X-ray Pair Distribution Function (XPDF)
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Diamond Proposal Number(s):
[16983, 19130, 20195, 21979, 22395, 20038]
Open Access
Abstract: Characterization of nanoscale changes in the atomic structure of amorphous materials is a profound challenge. Established X-ray and neutron total scattering methods typically provide sufficient signal quality only over macroscopic volumes. Pair distribution function analysis using electron scattering (ePDF) in the scanning transmission electron microscope (STEM) has emerged as a method of probing nanovolumes of these materials, but inorganic glasses as well as metal–organic frameworks (MOFs) and many other materials containing organic components are characteristically prone to irreversible changes after limited electron beam exposures. This beam sensitivity requires ‘low-dose’ data acquisition to probe inorganic glasses, amorphous and glassy MOFs, and MOF composites. Here, we use STEM-ePDF applied at low electron fluences (10 e-/Å2) combined with unsupervised machine learning methods to map changes in the short-range order with ca. 5 nm spatial resolution in a composite material consisting of a zeolitic imidazolate framework glass agZIF-62 and a 0.67([Na2O]0.9[P2O5])-0.33([AlO3/2][AlF3]1.5) inorganic glass. STEM-ePDF enables separation of MOF and inorganic glass domains from atomic structure differences alone, showing abrupt changes in atomic structure at interfaces with interatomic correlation distances seen in X-ray PDF preserved at the nanoscale. These findings underline that the average bulk amorphous structure is retained at the nanoscale in the growing family of MOF glasses and composites, a previously untested assumption in PDF analyses crucial for future non-crystalline nanostructure engineering.
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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):
[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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B18-Core EXAFS
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Diamond Proposal Number(s):
[11226]
Open Access
Abstract: Over 50 million people in South Asia are exposed to groundwater contaminated with carcinogenic arsenic(III). Photocatalyst-adsorbent composite materials are popularly developed for removing arsenic in a single-step water treatment. Here, As(III) is oxidised to As(V), which is subsequently removed via adsorption. We previously developed a component additive surface complexation model (CA-SCM) to predict the speciation of arsenic adsorbed onto TiO 2/Fe2O3 under different environmental conditions, using surface complexes taken from studies of single-phase minerals. In this work, we critically evaluate this approach, using experimental observations of the surface structures of arsenic adsorbed onto TiO 2/Fe2O3. Extended X-ray absorption fine structure spectroscopy (EXAFS) indicates significant As(III) surface precipitation, and the possible formation of tridentate 3C complexes. EXAFS was unable to identify As binding modes for TiO 2 and Fe2O3 surface complexes simultaneously, highlighting the challenge of analysing composite surfaces. FTIR and zeta potential analysis indicate that As(III)-Fe2O3 surface complexes are protonated at neutral pH, whilst As(III)-TiO 2, As(V)-Fe2O3 and As(V)-TiO 2 surface complexes are negatively charged. Our study confirms the speciation predicted by CA-SCM, particularly As(III) surface precipitation, but also introduces the possibility of tridentate As(III) at acidic pH. This study highlights how experiment and modelling can be combined to assess surface complexation on composite surfaces.
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Sep 2022
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B16-Test Beamline
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Diamond Proposal Number(s):
[23372]
Open Access
Abstract: Synchrotron X-ray diffraction (SXRD) strain analysis is well established for high crystalline materials such as metals and ceramics, however, previously it has not been used in Carbon Fibre Reinforced Polymer (CFRP) composites due to their complex turbostratic atomic structure. This paper will present the feasibility of using SXRD for fibre orientation and lattice strain mapping inside CFRPs. In particular, it is the first time that the radial and axial strains of carbon fibre crystal planes have been analysed and cross-validated via numerical multi-scale simulation in a two-scale manner. In order to simplify the analysis and provide comparable estimates, an UniDirectional (UD) CFRP formed into a well-established humpback bridge shape was used. The lattice strain estimates obtained from SXRD showed localised stress concentrations and effectively matched the numerical results obtained by modelling. The mean absolute percentage differences between the two were 25.80% and 28.50% in the radial and axial directions, respectively. Differences between the two measurements are believed to originate from the non-uniform thermal history, forming geometry and tool-part interaction which leads to localised residual strains in the laminate which are unable to be fully captured by the numerical simulation performed. The carbon fibre microstructures of the inner plies adjacent to the tool were found to be significantly influenced by these factors and therefore the largest errors were observed at these locations. The approach presented has significant promise and implications for research into the micromechanics of composite materials and areas for future improvement have been outlined.
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Aug 2022
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B21-High Throughput SAXS
I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[17972, 16970]
Abstract: Catalytically active materials for the enhancement of personalized protective equipment (PPE) could be advantageous to help alleviate threats posed by neurotoxic organophosphorus compounds (OPs). Accordingly, a chimeric protein comprised of a supercharged green fluorescent protein (scGFP) and phosphotriesterase from Agrobacterium radiobacter (arPTE) was designed to drive the polymer surfactant (S–)-mediated self-assembly of microclusters to produce robust, enzymatically active materials. The chimera scGFP-arPTE was structurally characterized via circular dichroism spectroscopy and synchrotron radiation small-angle X-ray scattering, and its biophysical properties were determined. Significantly, the chimera exhibited greater thermal stability than the native constituent proteins, as well as a higher catalytic turnover number (kcat). Furthermore, scGFP-arPTE was electrostatically complexed with monomeric S–, driving self-assembly into [scGFP-arPTE][S–] nanoclusters, which could be dehydrated and cross-linked to yield enzymatically active [scGFP-arPTE][S–] porous films with a high-order structure. Moreover, these clusters could self-assemble within cotton fibers to generate active composite textiles without the need for the pretreatment of the fabrics. Significantly, the resulting materials maintained the biophysical activities of both constituent proteins and displayed recyclable and persistent activity against the nerve agent simulant paraoxon.
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Dec 2021
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[22506]
Open Access
Abstract: Isotropy in microstructure and mechanical properties remains a challenge for laser powder bed fusion (LPBF) processed materials due to the epitaxial growth and rapid cooling in LPBF. In this study, a high-strength TiB2/Al-Cu composite with random texture was successfully fabricated by laser powder bed fusion (LPBF) using pre-doped TiB2/Al-Cu composite powder. A series of advanced characterisation techniques, including synchrotron X-ray tomography, correlative focussed ion beam–scanning electron microscopy (FIB-SEM), scanning transmission electron microscopy (STEM), and synchrotron in situ X-ray diffraction, were applied to investigate the defects and microstructure of the as-fabricated TiB2/Al-Cu composite across multiple length scales. The study showed ultra-fine grains with an average grain size of about 0.86 μm, and a random texture was formed in the as-fabricated condition due to rapid solidification and the TiB2 particles promoting heterogeneous nucleation. The yield strength and total elongation of the as-fabricated composite were 317 MPa and 10%, respectively. The contributions of fine grains, solid solutions, dislocations, particles, and Guinier–Preston (GP) zones were calculated. Failure was found to be initiated from the largest lack-of-fusion pore, as revealed by in situ synchrotron tomography during tensile loading. In situ synchrotron diffraction was used to characterise the lattice strain evolution during tensile loading, providing important data for the development of crystal-plasticity models.
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Sep 2021
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I19-Small Molecule Single Crystal Diffraction
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Diamond Proposal Number(s):
[18768, 22411]
Open Access
Abstract: Human society is facing—among other environmental threats—an enormous challenge due to human activities. The extensive use of high-tech devices and electronics equipment in the daily life makes, among others, rare-earth elements (REEs) recovery from secondary sources highly required. Here, a novel bioMOF-based single-walled carbon nanotube buckypaper (SWCNTBP) is presented as a new and efficient composite material (BioMOF@SWCNT-BP). The flexible and highly crystalline metal–organic framework (MOF), prepared from the natural amino acid L-threonine, has been homogeneously dispersed within the tangled net of a self-standing SWCNT-BP for lanthanides recovery from water. This MOF-carbon-based membrane exhibits high efficiency, either in static or dynamic regimes, in the recovery of lanthanides from aqueous streams outperforming the state-of-the-art. The capture performances of BPs are successfully improved after incorporation of such MOF featuring hexagonal functional channels decorated with the threonine amino acid residues, pointing toward the accessible void spaces, which boosts the capture properties of the final membrane, providing the adaptable functional environment to interact with lanthanides. This material's preparation presents also a potential for large-scale applications with a potential benefit on natural aquatic ecosystems as well. It is highly demanded because REEs from non-recycled waste materials are potential pollutants for surface waters.
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Aug 2021
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I15-Extreme Conditions
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Diamond Proposal Number(s):
[9902, 8858]
Abstract: The tensile fractured surfaces of ZrTi-based bulk metallic glass and composite samples were studied using synchrotron X-ray total scattering. The scanned areas contain different shear bands densities. The shear bands create localized atomic strains, which in turn cause more ordered atomic structures. Such structural changes were reflected in the scattering structure factor, i.e. the higher the density of the shear bands, the higher the scattering structure factor. Similar phenomenon was also found in the metallic glass composite.
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Aug 2021
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I12-JEEP: Joint Engineering, Environmental and Processing
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Ying
Wang
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Xu
Xu
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Wenxia
Zhao
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Nan
Li
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Samuel A.
Mcdonald
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Yuan
Chai
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Michael D.
Atkinson
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Katherine J.
Dobson
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Stefan
Michalik
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Yingwei
Fan
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Philip J.
Withers
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Xiaorong
Zhou
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Timothy L.
Burnett
Diamond Proposal Number(s):
[20226]
Open Access
Abstract: The damage mechanisms and load redistribution taking place under high temperature (350°C), high cycle fatigue (HCF) of TC17 titanium alloy/unidirectional SiC fibre composites have been investigated in situ using synchrotron X-ray computed tomography (CT) and X-ray diffraction (XRD) under two stress amplitudes. The three-dimensional morphology of the fatigue crack and fibre fractures has been mapped by CT. At low stress amplitude, stable growth occurs with matrix cracking deflecting by 50-100 µm in height as it bypasses the bridging fibres. At higher stress amplitude, loading to the peak stress led to a burst of fibre fractures giving rise to rapid crack growth. Many of the fibre fractures occurred 50-300 µm above/below the matrix crack plane during rapid growth, contrary to that in the stable growth stage, leading to extensive fibre pull-out on the fracture surface. The changes in fibre loading, interfacial stress, and the extent of fibre-matrix debonding in the vicinity of the crack have been mapped over the fatigue cycle and after the rapid growth by XRD. The fibre/matrix interfacial sliding extends up to 600 µm (in the stable-growth zone) or 700 µm (in the rapid-growth zone) either side of the crack plane. The direction of interfacial shear stress reverses over the loading cycle, with the maximum frictional sliding stress reaching ∼55 MPa in both regimes. In accordance with previous studies, it is possible that a degradation in fibre strength at elevated temperature is responsible for bursts of fibre fracture and rapid crack growth under higher stress amplitude.
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May 2021
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I13-2-Diamond Manchester Imaging
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G. R.
Parker
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D. S.
Eastwood
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M.
Storm
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K.
Vitharana
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E. M.
Heatwole
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I.
Lopez-Pulliam
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R. M.
Broilo
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P. M.
Dickson
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A.
Martinez
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Christoph
Rau
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N. K.
Bourne
Diamond Proposal Number(s):
[15068, 16650, 18198]
Abstract: High-resolution synchrotron x-ray radiography with computed tomography is used to observe the evolution of porosity created by thermal exposure in two HMX-based polymer-bonded explosive compositions; LX-04 and BX-63. The measurements were made in situ, over an extended period of time, during which the samples were heated on a slow-rate thermal trajectory. The tests ended with thermal-runaway to ignition after which the samples were consumed by combustion. The primary means of damage appears to be from mechanical debonding of the HMX-binder interface with secondary contribution from chemical decomposition. Confinement and binder properties affect the amount of porosity and permeability that develops. Additionally, observations were made describing the emergence and structure of an internal ignition volume, the formation and transport of a pre-ignition melt layer, and how the early stages of combustion were affected by material morphology, mechanical confinement and melt. The contact angle between molten HMX and the fluoropolymer, Viton A, is also presented. For the first time we have time-resolved x-ray images of ignition in sufficient detail to verify the mechanism of cookoff in polymer-bonded explosive compositions.
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Apr 2021
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