I13-2-Diamond Manchester Imaging
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Jishizhan
Chen
,
Alissa
Parmenter
,
Aikta
Sharma
,
Elis
Newham
,
Eral
Bele
,
Sebastian
Marussi
,
Andrew A.
Pitsillides
,
Nick J.
Terrill
,
Christopher
Mitchell
,
Himadri S.
Gupta
,
Peter
Lee
Diamond Proposal Number(s):
[29784]
Open Access
Abstract: Lower back pain is linked to vertebral biomechanics, with vertebral endplates (VEPs) playing a key role. Finite element modelling (FEM) is a powerful tool for studying VEP biomechanics but relies on accurate material property inputs, which remain difficult to obtain. Synchrotron computed tomography (sCT) enables detailed visualisation of intact VEP microstructure under near-physiological loads in situ, with three-dimensional strain fields obtained by digital volume correlation (DVC) providing experimental reference data for FEM validation. We applied inverse finite element methodologies to estimate of the elastic properties of rat VEPs by integrating DVC data into an image-based FE model. Our pipeline estimated an elastic modulus of 129 MPa and a Poisson’s ratio of 0.24 in a rat lumbar segment. The first-order Wasserstein distance between FEM and DVC strain distributions ranged from 0.08% to 0.28%, with Bland–Altman analysis revealing <95% spatial agreement between FEM-predicted and DVC-derived strains across multiple loading steps. Pipeline measurement consistency was evaluated across multiple rat lumbar FE models (n = 3), yielding an estimated VEP elastic modulus = 153 ± 21 MPa and a Poisson’s ratio = 0.28 ± 0.03. Regional variations of strain distribution in VEP bodies and protrusions were also identified (strain Wasserstein distance of 0.10%–0.48%). Our work demonstrates the efficacy of the established pipeline in estimating the isotropic elastic modulus and Poisson’s ratio of VEPs using FEMs in a physiologically relevant, complex load transfer system. As sCT data becomes available, our pipeline lays the foundations for estimating VEP properties in larger animals and humans.
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Mar 2026
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I12-JEEP: Joint Engineering, Environmental and Processing
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Imogen
Cowley
,
Harry E.
Chapman
,
Sebastian
Marussi
,
Xianqiang
Fan
,
David
Rees
,
Tristan
Fleming
,
Yunhui
Chen
,
Alexander
Rack
,
Robert C.
Atwood
,
Martyn A.
Jones
,
Samuel J.
Clark
,
Chu Lun Alex
Leung
,
Peter D.
Lee
Diamond Proposal Number(s):
[28804]
Open Access
Abstract: In situ synchrotron studies of Directed Energy Deposition (DED) additive manufacturing provide unique process insights, using high-resolution spatial and temporal observations to reveal melt pool dynamics, phase evolution, and defect formation mechanisms. However, capturing these phenomena under industrially relevant conditions remains a challenge. Here, a second-generation DED apparatus is presented that replicates industrially relevant process conditions whilst enabling multi-modal in situ monitoring, including synchrotron X-ray radiography and diffraction, infrared (IR) imaging, inline coherent imaging (ICI), and optical imaging. The equipment, termed the Blown-powder Additive Manufacturing Process Replicator-II (BAMPR-II), also facilitates a range of unique process adaptations including the application of heat, magnetic fields, and ultrasound. Two case studies are described demonstrating how BAMPR-II reveals the underlying phenomena controlling DED, including: (1) simultaneous X-ray and ICI imaging to capture cracking mechanisms during DED; and (2) X-ray imaging of DED illustrating how magnetic fields can control flow in the melt pool.
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Feb 2026
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[31855]
Open Access
Abstract: Directed energy deposition (DED) laser additive manufacturing (AM) is a promising technique for building complex components and performing repair applications. However, large defects can form through coalescence of argon bubbles from the feedstock powder, potentially reducing end-component mechanical performance. Here, we used correlative high-speed synchrotron X-ray and infrared imaging, coupled with multiphysics modelling to develop a strategy to control defect formation. We demonstrate that the bubble dynamics can be controlled by appropriately modulating the laser power, temporarily disrupting the Marangoni flow, enabling bubble release. The bubble control mechanisms discovered here provide a way to achieve defect-lean AM.
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Sep 2025
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I12-JEEP: Joint Engineering, Environmental and Processing
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Barbara
Bonechi
,
Margherita
Polacci
,
Fabio
Arzilli
,
Giuseppe
La Spina
,
Jean-Louis
Hazemann
,
Richard A.
Brooker
,
Robert
Atwood
,
Sebastian
Marussi
,
Peter D.
Lee
,
Roy A.
Wogelius
,
Jonathan
Fellowes
,
Mike R.
Burton
Diamond Proposal Number(s):
[28538]
Open Access
Abstract: Transitions in eruptive style during volcanic eruptions strongly depend on how easily gas and magma decouple during ascent. Stronger gas-melt coupling favors highly explosive eruptions, whereas weaker coupling promotes lava fountaining and lava flows. The mechanisms producing these transitions are still poorly understood because of a lack of direct observations of bubble dynamics under natural magmatic conditions. Here, we combine x-ray radiography with a novel high-pressure/high-temperature apparatus to observe and quantify in real-time bubble growth and coalescence in basaltic magmas from 100 megapascals to surface. For low-viscosity magmas, bubbles coalesce and recover a spherical shape within 3 seconds, implying that, for lava fountaining activity, gas and melt remain coupled during the ascent up to the last hundred meters of the conduit. For higher-viscosity magmas, recovery times become longer, promoting connected bubble pathways. This apparatus opens frontiers in unraveling magmatic/volcanic processes, leading to improved hazard assessment and risk mitigation.
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Aug 2024
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I12-JEEP: Joint Engineering, Environmental and Processing
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Lorna
Sinclair
,
Oliver
Hatt
,
Samuel J.
Clark
,
Sebastian
Marussi
,
Elena
Ruckh
,
Robert C.
Atwood
,
Martyn
Jones
,
Gavin J.
Baxter
,
Chu Lun Alex
Leung
,
Iain
Todd
,
Peter D.
Lee
Diamond Proposal Number(s):
[20096]
Open Access
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Jul 2024
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Kai
Zhang
,
Yunhui
Chen
,
Sebastian
Marussi
,
Xianqiang
Fan
,
Maureen
Fitzpatrick
,
Shishira
Bhagavath
,
Marta
Majkut
,
Bratislav
Lukic
,
Kudakwashe
Jakata
,
Alexander
Rack
,
Martyn A.
Jones
,
Junji
Shinjo
,
Chinnapat
Panwisawas
,
Chu Lun Alex
Leung
,
Peter D.
Lee
Open Access
Abstract: Porosity in directed energy deposition (DED) deteriorates mechanical performances of components, limiting safety-critical applications. However, how pores arise and evolve in DED remains unclear. Here, we reveal pore evolution mechanisms during DED using in situ X-ray imaging and multi-physics modelling. We quantify five mechanisms contributing to pore formation, migration, pushing, growth, removal and entrapment: (i) bubbles from gas atomised powder enter the melt pool, and then migrate circularly or laterally; (ii) small bubbles can escape from the pool surface, or coalesce into larger bubbles, or be entrapped by solidification fronts; (iii) larger coalesced bubbles can remain in the pool for long periods, pushed by the solid/liquid interface; (iv) Marangoni surface shear flow overcomes buoyancy, keeping larger bubbles from popping out; and (v) once large bubbles reach critical sizes they escape from the pool surface or are trapped in DED tracks. These mechanisms can guide the development of pore minimisation strategies.
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Feb 2024
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[2370]
Open Access
Abstract: Surface roughness controls the mechanical performance and durability (e.g., wear and corrosion resistance) of laser powder bed fusion (LPBF) components. The evolution mechanisms of surface roughness during LPBF are not well understood due to a lack of in situ characterisation methods. Here, we quantified key processes and defect dynamics using synchrotron X-ray imaging and ex situ optical imaging and explained the evolution mechanisms of side-skin and top-skin roughness during multi-layer LPBF of Ti-6AI-4V (where down-skin roughness was out of the project scope). We found that the average surface roughness alone is not an accurate representation of surface topology of an LPBF component and that the surface topology is multimodal (e.g., containing both roughness and waviness) and multiscale (e.g., from 25 µm sintered powder features to 250 µm molten pool wavelength). Both roughness and topology are significantly affected by the formation of pre-layer humping, spatter, and rippling defects. We developed a surface topology matrix that accurately describes surface features by combining 8 different metrics: average roughness, root mean square roughness, maximum profile peak height, maximum profile valley height, mean height, mean width, skewness, and melt pool size ratio. This matrix provides a guide to determine the appropriate linear energy density to achieve the optimum surface finish of Ti-6AI-4V thin-wall builds. This work lays a foundation for surface texture control which is critical for build design, metrology, and performance in LPBF.
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Oct 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28804]
Open Access
Abstract: Melt flow is critical to build quality during additive manufacturing (AM). When an external magnetic field is applied, it causes forces that alter the flow through the thermoelectric magnetohydrodynamic (TEMHD) effect, potentially altering the final microstructure. However, the extent of TEMHD forces and their underlying mechanisms, remain unclear. We trace the flow of tungsten particles using in situ high-speed synchrotron X-ray radiography and ex situ tomography to reveal the structure of TEMHD-induced flow during directed energy deposition AM (DED-AM). When no magnetic field is imposed, Marangoni convection dominates the flow, leading to a relatively even particle distribution. With a magnetic field parallel to the scan direction, TEMHD flow is induced, circulating in the cross-sectional plane, causing particle segregation to the bottom and side of the pool. Further, a downward magnetic field causes horizontal circulation, segregating particles to the other side. Our results demonstrate that TEMHD can disrupt melt pool flow during DED-AM.
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Jun 2023
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I13-2-Diamond Manchester Imaging
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Diamond Proposal Number(s):
[19354, 22976]
Open Access
Abstract: Laser powder bed fusion (LPBF) additive manufacturing of 2XXX series Al alloys could be used for low volume specialist aerospace components, however, such alloys exhibit hot cracking susceptibility that can lead to component failure. In this study, we show two approaches to suppress the formation of hot cracks by controlling solidification behaviour using: (1) TiB2 additions; and (2) optimisation of LPBF process parameters. Using high-speed synchrotron X-ray radiography, we monitored LPBF of Al-2139 in situ, with and without TiB2 under a range of process conditions. In situ X-ray radiography results captured the crack growth over 1.0 ms at a rate of ca. 110 mm s-1, as well as pore evolution, wetting behaviour and build height. High-resolution synchrotron X-ray computed tomography (sCT) was used to measure the volume fraction of defects, e.g. hydrogen pores and microcracks, in the as-built LPBF samples. Our results show adding TiB2 in Al-2139 reduces the volume of cracks by up to 79 % under a volume energy density of 1000 to 5000 J mm-3, as well as reducing the average length, breadth, and surface area of cracks.
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Jun 2023
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I12-JEEP: Joint Engineering, Environmental and Processing
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Diamond Proposal Number(s):
[28804]
Open Access
Abstract: Directed energy deposition (DED) is a promising additive manufacturing technique for repair; however, DED is prone to surface waviness (humping) in thin-walled sections, which increases residual stresses and crack susceptibility, and lowers fatigue performance. Currently, the crack formation mechanism in DED is not well understood due to a lack of operando monitoring methods with high spatiotemporal resolution. Here, we use inline coherent imaging (ICI) to optically monitor surface topology and detect cracking in situ, coupled with synchrotron X-ray imaging for observing sub-surface crack healing and growth. For the first time, ICI was aligned off-axis (24° relative to laser), enabling integration into a DED machine with no alterations to the laser delivery optics. We achieved accurate registration laterally (<10 µm) and in depth (<3 µm) between ICI measurements and the laser beam position using a single-element MEMS scanner and a custom calibration plate. ICI surface topology is verified with corresponding radiographs (correlation >0.93), directly tracking surface roughness and waviness. We intentionally seed humping into thin-wall builds of nickel super-alloy CM247LC, locally inducing cracking in surface valleys. Crack openings as small as 7 µm were observed in situ using ICI, including sub-surface signal. By quantifying both humping and cracking, we demonstrate that ICI is a viable tool for in situ crack detection.
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Apr 2023
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