I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[22517]
Open Access
Abstract: Catastrophic failure is the end result of progressive localisation of damage creating brittle failure on a variety of system scales in the Earth. However, the factors controlling this evolution, and the relationship between deformation and the resulting earthquake hazard, are not well constrained. Here we address the question of how to adapt operational controls in a strain-inducing laboratory experiment so as to minimize associated microseismicity. We simultaneously image the induced damage using x-rays at a synchrotron, and detect acoustic emissions which can be fed back to change operational controls on the experiment. We confirm that using continuous servo-control based on acoustic emission event rate not only slows down deformation compared to standard constant strain rate loading, but also suppresses events of all sizes, including extreme events. We develop a new model that explains this observation, based on the observed evolution of microstructural damage and the fracture mechanics of subcritical crack growth. The model is independently consistent with the observed stress history and acoustic emission statistics. Our results imply that including seismic event rate control may improve risk management of induced seismicity over a range of event magnitudes, if similar processes are relevant at larger scales.
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Jun 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Emily C.
Bamber
,
Margherita
Polacci
,
F.
Arzilli
,
Giuseppe
La Spina
,
Elisa
Biagioli
,
Jorge E.
Romero
,
Jean-Louis
Hazemann
,
Richard
Brooker
,
Robert
Atwood
,
Mike
Burton
Diamond Proposal Number(s):
[31529]
Open Access
Abstract: Investigating the textural properties and 3D geometry of the connected pore network in volcanic products provides insight into magma ascent processes, due to their influence on magma permeability, outgassing efficiency and explosivity. Here, we used X-ray computed microtomography to investigate vesicle textures in tephra from the 2021 Tajogaite eruption (La Palma, Spain) and the relationship between these pore network parameters and eruptive style. We report a 3D dataset of pore network parameters for lapilli clasts collected throughout the eruption, associated with different eruptive styles (ash-rich jets, lava fountains, Strombolian activity). In clasts from Strombolian activity, the lower vesicle number density (VND) and tortuosity factor (m) suggests that there are fewer vesicles and that the channels which connect them are less tortuous than in clasts from fountain and ash-rich jet activity, favouring a lower degree of gas–melt coupling and thus, more efficient outgassing. Instead, for clasts of lava fountain and ash-rich jet activity, the higher VND and m suggest a higher number of vesicles connected by more tortuous channels, promoting some degree of gas–melt coupling and thus, less efficient outgassing. However, in clasts from ash-rich jets, the presence of narrower channels, as suggested by the lower throat-pore size ratio, favours a greater degree of gas–melt coupling with respect to fountain activity, leading to magma fragmentation. This work highlights the importance of textural and pore network analyses in understanding eruption dynamics, and provides a case study for investigating the interplay between pore network parameters, magma permeability and ascent dynamics for low-viscosity magmas.
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Jun 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[37256]
Open Access
Abstract: Fertilisers play a key role in agriculture, providing key nutrients needed by crops to ensure a secure food supply. However, with increasing prices and rising environmental concerns, there is a growing need to rely on alternative and sustainable fertiliser sources, introducing the opportunity to use organic amendments to formulate organo-mineral fertilisers (OMF). Despite their environmental advantages, the inherent variability in composition of organic amendments within OMF poses a challenge for their standardization. This study aims to use OMF derived from anaerobic digestate and coupled with carbon capture technologies to analyze for its physical characteristics and chemical composition using neutron computed tomography (NCT), X-ray computed tomography (XCT) and Raman spectroscopy (RS). This is a feasibility study to assess using non-destructive techniques on OMF as previously this has not been explored. This work represents the first attempt to utilize a combination of imaging techniques to investigate on OMF and demonstrates their feasibility for measuring the variability between individual samples. This is a proof-of-concept study which shows that combining NCT and XCT can provide images on how uniformly packed each OMF pellet are. The use of RS is to characterize OMF is more challenging largely due to the high fluorescence background arising from its matrix. This study needs to be further developed to enable image-based analysis using machine learning algorithms to determine characteristics of large batches of OMF. Further development is needed building on this work to quantify OMF pellet characteristics so that it can be confidently used as novel fertilisers in agriculture.
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Jun 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
I15-Extreme Conditions
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Diamond Proposal Number(s):
[21147, 19558]
Abstract: The strength-ductility trade-off in additively manufactured (AM) β Ti alloys remains a significant challenge. In this study, we employed a cost-effective in-situ alloying laser powder bed fusion approach with optimized processing parameters to fabricate a nearly fully dense, chemically homogeneous β Ti-12Mo alloy. We then examined how solution-treatment duration influences the tensile behavior of the AM Ti-12Mo alloy. The optimally solution-treated alloys exhibited high tensile yield strength (725–741 MPa) and commendable ductility (22–36 %) along both the 0° and 90° orientations relative to the build direction. Focusing on the underlying deformation mechanisms perpendicular to the build direction, we report a uniform elongation of 17.9 % and a pronounced strain hardening rate (∼2300 MPa at 4 %), which we elucidate via in-situ high-energy synchrotron X-ray diffraction and microstructural characterization. The high yield strength is primarily attributed to the presence of Mo-lean embryonic athermal ω nanoparticles. During plastic deformation, both twinning and phase transformation contribute to the high strain hardening rate. At the early stage (strain < 1.9 %), deformation is dominated by {332}< 113 >β twinning, whereas at later stages, the deformation-induced α'' phase becomes significant. The volume fraction of α'' phase increases with strain, supporting the continuous hardening. Notably, irrational {112}< 751 >β, secondary {112}< 111 >β, and {130}< 310 >α'' nano-twins confine the primary structures to nanograins and sustain strain hardening. This study sheds light on designing high-performance β Ti-12Mo alloy via AM followed by heat treatment.
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Jun 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
I22-Small angle scattering & Diffraction
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Diamond Proposal Number(s):
[35872, 30439]
Open Access
Abstract: Al-Zn-Mg-Cu alloys are known for their exceptional mechanical properties, primarily achieved through precipitation hardening. This study investigates the dynamic precipitation behaviour in a pre-aged AA7075 alloy under uniaxial tension and cross-die forming at 180 °C. In-situ synchrotron small-angle X-ray scattering (SAXS) revealed a non-monotonic precipitate growth behaviour under uniaxial tension, where growth was initially accelerated but slowed as strain exceeded 7%. Synchrotron SAXS and wide-angle X-ray scattering (WAXS) were used to simultaneously map precipitation and deformation across regions with varied strain conditions in samples subjected to warm cross-die forming demonstrating local variations in precipitation and dislocation arrangement, along with an inverse dependence of precipitate growth on plastic strain. A modified Kampmann-Wagner Numerical (KWN) model was applied to successfully predict the overall precipitation behaviour, highlighting that the competing effects of deformation-induced vacancies enhancing diffusivity and the reduction of supersaturation due to precipitate growth are of primary importance, while the potential influence of strain path in monotonic deformation is of secondary significance.
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May 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Open Access
Abstract: This study aims to understand the interplay between strength and ductility in metastable β-Ti alloys based on eutectoid and neutral elements. A low-cost ternary Ti-7Cr-4Sn alloy was prepared by furnace cooling from the single β region at the end of the primary processing. Although isothermal ω, a nano-precipitation generally considered to embrittle the material, is present in the obtained ultra-fine microstructure, the material still exhibits a balanced strength and ductility, with a yield stress of 1067 MPa and elongation of about 10%. The obtained tensile properties surpass traditional primary processed Ti-6Al-4V, and are comparable to a range of expensive commercial high-strength aerospace Ti alloys. Multiple microstructural features, including grain boundary α (αGB), short rod shape primary α (αP), isothermal ω (ωiso) and ω assisted secondary α (αs) are characterised within the room temperature microstructure. Microstructural analysis reveals that strong Cr segregation in the β phase and slight partitioning of Sn between the α and β phase strengthens the β phase while also preserving ductility in the alloy. This results in a microstructure dominated by the ductile α phase and sub-micron α grain boundaries. This study also discusses the evolution of these microstructural features during different stages of cooling from β matrix, substantiating a promising alloy design strategy for affordable high-performance new Ti alloys.
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May 2025
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B18-Core EXAFS
I11-High Resolution Powder Diffraction
I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[9610, 12763, 9019, 32893, 11574]
Open Access
Abstract: Iron-based superconductors have attracted much attention for their high superconducting temperatures and high upper critical fields, which make them promising candidates for application as well as fundamentally important for our understanding of superconductivity. One feature of these superconductors is their ability to intercalate and deintercalate species from between their iron-containing layers, something not available in cuprate high-temperature superconductors or niobium-based conventional superconductors used in technologies. This provides an opportunity for switchable changes in the superconducting properties as a function of chemical conditions, but the resulting structures are often hard to characterize due to loss of crystallinity and sometimes the formation of multiphase products. Here, we explore both the synthesis and decomposition of potassium and ammonia-intercalated iron selenide superconductors through in situ powder X-ray diffraction. We report a complete phase diagram including two new solution-stable ammonia-rich phases and several metastable forms. We give accurate characterization of the reported ammonia-poor forms using a combination of neutron and X-ray powder diffraction, using an innovative supercell approach to describe the phase breadth within the samples. These results give rare insight into stepwise changes occurring in solids along multiple reaction pathways, which demonstrate the importance of in situ diffraction techniques.
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May 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[26767]
Open Access
Abstract: Lithium ion batteries are pivotal for clean energy storage and mitigating climate change. In this study, we employ operando synchrotron X-ray computed tomography to investigate the dynamic evolution of battery cathode microstructure. We focus on tracking changes in porosity and pore size distribution at the microscale and cathode thickness at the macroscale during the lithiation and delithiation processes within a commercially configured battery. Image quality was enhanced using both conventional image processing methods and a Super-Resolution Convolutional Neural Network (SRCNN) model. Our findings revealed a slight increase in the cathode solid volume fraction and specific surface area as the battery transitioned from its pristine state to fully lithiated, followed by a reduction during delithiation. This behavior was attributed to the expansion of the cathode material and phase transitions during lithiation, which split larger pores into smaller ones, as evidenced by the increase in surface area. Cathode thickness also exhibited expansion during lithiation and contraction during delithiation. These results offer valuable insights into the structural changes that contribute to battery aging, helping researchers better understand how these different parameters change over time. This understanding is crucial for designing more durable and sustainable batteries in the future, both in terms of specific design and material selection, to enhance resistance during charge and discharge cycles to improve performance and longevity.
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Apr 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[26608]
Open Access
Abstract: Fe-based metallic glasses universally show an exceptionally low coefficient of thermal expansion due to their ferromagnetic interactions. This effect is called the Invar effect and is rarely seen in crystalline materials. With the loss of ferromagnetic ordering at the Curie temperature, the coefficient of thermal expansion increases by up to one order of magnitude. It has been shown that only Fe is responsible for generating and controlling the Invar effect in Fe-based metallic glasses. However, there is no atomistic explanation of how the disordered atomic arrangement enables it. By combining experimental data of synchrotron X-ray diffraction and extended X-ray absorption fine structure experiments via reverse Monte Carlo modeling, we obtain a series of 3D structural models of an (Fe71.2B24Y4.8)96Nb4 bulk metallic glass. Comparison with related ternary metallic glasses shows remarkably similar short- and medium-range order. The models reveal that the Invar effect is not caused by structural rearrangements or change in coordination number. Instead, the magnetic contributions to the interatomic forces stabilize the structure in the ferromagnetic state.
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Apr 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[26730]
Open Access
Abstract: Hydrogen (H2) storage in porous geological formations offers a promising means to balance supply and demand in the renewable energy sector, supporting the energy transition. Important unknowns to this technology include the H2 fluid flow dynamics through the porous medium which affect H2 injectivity and recovery. We used time-resolved X-ray computed microtomography to image real-time unsteady and steady state injections of H2 and brine (2 M KI) into a Clashach sandstone core at 5 MPa and ambient temperature. In steady state injections, H2 entered the brine-saturated rock within seconds, dispersing over several discrete pores. Over time, some H2 ganglia connected, disconnected and then reconnected from each other (intermittent flow), indicating that the current presumption of a constant connected flow pathway during multiphase fluid flow is an oversimplification. Pressure oscillations at the sample outlet were characterized as red noise, supporting observations of intermittent pore-filling. At higher H2 fractional flow the H2 saturation in the pore space increased from 20-22 % to 28 %. Average Euler characteristics were generally positive over time at all H2 flow fractions, indicating poorly connected H2 clusters and little control of connectivity on the H2 saturation. In unsteady state injections, H2 displaced brine in sudden pore-filling events termed Haines jumps, which are key to understanding fluid dynamics in porous media. Our results suggest a lower H2 storage capacity in sandstone aquifers with higher injection-induced hydrodynamic flow and suggest a low H2 recovery. For more accurate predictions of H2 storage potential and recovery, geological models should incorporate energy-dissipating processes such as Haines jumps.
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Apr 2025
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