Search Results

You searched for all publications:

with publication states 'Published' 'Published (Approved)'

Search Again...

These results include publications that have not yet been reviewed and processed by Diamond Light Source. To view only processed publications click here.

You can use the folder icon under Actions to collate papers as required. You can then click on View Folder in the left-hand navigation to review and/or download your folder.

Exact matches
Related results

3 items found (0 items not approved), displaying all items.1

Instruments / Technical Area	Publication Details	Published
I13-2-Diamond Manchester Imaging	Mechanisms of gas and shrinkage porosity formation in solidifying shear bands Shishira Bhagavath , Zhixuan Gong , Tim Wigger , Saurabh Shah , Bita Ghaffari , Mei Li , Shashidhara Marathe , Shyamprasad Karagadde , Peter D. Lee Journal Of Materials Processing Technology 26 DOI: 10.1016/j.jmatprotec.2021.117338 Diamond Proposal Number(s): [22053] Show Abstract ▼ Abstract: In specialised solidification processing techniques such as High Pressure Die Casting, Twin-Roll Casting and others, an additional external deformation load is applied to achieve the required shape, leading to the formation of microstructural features such as shear bands. The mechanism for forming these features is believed to be dependent on dynamically evolving strain fields, which are dependent on the local solid fraction, applied strain rates and casting geometry. To investigate this, a semisolid ( 50 % solid fraction) Al-10 wt.% Cu alloy is isothermally injected into a bespoke die using a custom-designed thermo-mechanical rig. The semisolid deformation, formation of Cu-rich dilatant bands and subsequent pore nucleation and growth are captured using fast synchrotron X-ray radiography. The local normal and shear strains acting on the mush are quantified using Digital image correlation to identify the dilatant shear bands and the dominant local strain component. Correlating the radiographs with strain maps reveals that gas pores within the dilated interstices grow, while those in compressed regions are squeezed out. A linear correlation between accumulated volumetric strain and porosity volume fraction demonstrates that higher dilations give rise to a local increase in both gas and shrinkage porosity.	Aug 2021
I13-2-Diamond Manchester Imaging	Time resolved in-situ multi-contrast X-ray imaging of melting in metals Lorenzo Massimi , Samuel J. Clark , Sebastian Marussi , Adam Doherty , Saurabh M. Shah , Joachim Schulz , Shashidhara Marathe , Christoph Rau , Marco Endrizzi , Peter D. Lee , Alessandro Olivo Scientific Reports 12 DOI: 10.1038/s41598-022-15501-2 Diamond Proposal Number(s): [23760] Open Access Show Abstract ▼ Abstract: In this work, the application of a time resolved multi-contrast beam tracking technique to the investigation of the melting and solidification process in metals is presented. The use of such a technique allows retrieval of three contrast channels, transmission, refraction and dark-field, with millisecond time resolution. We investigated different melting conditions to characterize, at a proof-of-concept level, the features visible in each of the contrast channels. We found that the phase contrast channel provides a superior visibility of the density variations, allowing the liquid metal pool to be clearly distinguished. Refraction and dark-field were found to highlight surface roughness formed during solidification. This work demonstrates that the availability of the additional contrast channels provided by multi-contrast X-ray imaging delivers additional information, also when imaging high atomic number specimens with a significant absorption.	Jul 2022
I13-2-Diamond Manchester Imaging	In situ X-ray imaging of hot cracking and porosity during LPBF of Al-2139 with TiB2 additions and varied process parameters David T. Rees , Chu Lun Alex Leung , Joe Elambasseril , Sebastian Marussi , Saurabh Shah , Shashidhara Marathe , Milan Brandt , Mark Easton , Peter D. Lee Materials & Design 15 DOI: 10.1016/j.matdes.2023.112031 Diamond Proposal Number(s): [19354, 22976] Open Access Show Abstract ▼ 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.	Jun 2023

Publications Database

Search Results

You searched for all publications:

Search Again...

Subject Areas (check all that apply) select all

Instruments used to collect data (check all that apply) select all

Collaborations involved (check all that apply) select all

Diamond Offline Facilities used

Relevant Technical Areas (check all that apply) select all

Menu for Anonymous User