Wang, B;
Tan, D;
Lee, TL;
Khong, JC;
Wang, F;
Eskin, D;
Connolley, T;
... Mi, J; + view all
(2018)
Ultrafast synchrotron X-ray imaging studies of microstructure fragmentation in solidification under ultrasound.
Acta Materialia
, 144
pp. 505-515.
10.1016/j.actamat.2017.10.067.
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Abstract
Ultrasound processing of metal alloys is an environmental friendly and promising green technology for liquid metal degassing and microstructural refinement. However many fundamental issues in this field are still not fully understood, because of the difficulties in direct observation of the dynamic behaviours caused by ultrasound inside liquid metal and semisolid metals during the solidification processes. In this paper, we report a systematic study using the ultrafast synchrotron X-ray imaging (up to 271,554 frame per second) technique available at the Advanced Photon Source, USA and Diamond Light Source, UK to investigate the dynamic interactions between the ultrasonic bubbles/acoustic flow and the solidifying phases in a Bi-8%Zn alloy. The experimental results were complimented by numerical modelling. The chaotic bubble implosion and dynamic bubble oscillations were revealed in-situ for the first time in liquid metal and semisolid metal. The fragmentation of the solidifying Zn phases and breaking up of the liquid-solid interface by ultrasonic bubbles and enhanced acoustic flow were clearly demonstrated and agreed very well with the theoretical calculations. The research provides unambiguous experimental evidence and robust theoretical interpretation in elucidating the dominant mechanisms of microstructure fragmentation and refinement in solidification under ultrasound.
| Type: | Article |
|---|---|
| Title: | Ultrafast synchrotron X-ray imaging studies of microstructure fragmentation in solidification under ultrasound |
| Open access status: | An open access version is available from UCL Discovery |
| DOI: | 10.1016/j.actamat.2017.10.067 |
| Publisher version: | https://doi.org/10.1016/j.actamat.2017.10.067 |
| Language: | English |
| Additional information: | Copyright © 2017 Acta Materialia Inc. Published by Elsevier Ltd. This is an open access article under the CC BY license (http://creativecommons.org/licenses/by/4.0/). |
| Keywords: | Ultrafast synchrotron X-ray imaging, Ultrasonic bubble implosion & oscillation, Microstructure fragmentation & refinement, Solidification, Ultrasound processing |
| UCL classification: | UCL UCL > Provost and Vice Provost Offices > UCL BEAMS UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of the Built Environment UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of the Built Environment > Bartlett School Env, Energy and Resources |
| URI: | https://discovery.ucl.ac.uk/id/eprint/10074990 |
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