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The Use of Ultrasonic Technology in the Treatment of Light...
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The Use of Ultrasonic Technology in the Treatment of Light Alloys

A special issue of Metals (ISSN 2075-4701). This special issue belongs to the section "Additive Manufacturing".

Deadline for manuscript submissions: closed (31 December 2020) | Viewed by 11304

Special Issue Editor

Dr. Hélder Puga

E-Mail Website
Guest Editor
Center for Microelectromechanical Systems, Mechanical Department, University of Minho, 4710-057 Braga, Portugal
Interests: Al and Mg alloys; melt degassing; alloy refinement; ultrasonic processing; FEA optimization of ultrasonic system; advanced casting manufacture; aluminium foam; micro and nano-reinforced lightweight alloys
Special Issues, Collections and Topics in MDPI journals

Special Issue Information

Dear Colleagues,

The currently available processing technologies are limiting and, hence, there is an ongoing search for new components with higher performance and lower production costs. Thus, new affordable processing techniques to process novel materials/alloys, that are both environmentally friendly and extremely effective, are a must to remove this bottleneck. During recent years, we have been confronted with new developments in the casting and manufacturing light alloys, namely, due to the demand for new degassing and refinement techniques of liquid alloys. Acoustic energy is a valuable alternative to the current melt treatment techniques used to increase the mechanical properties and soundness of Al- and Mg-based components. During the application of high intensity ultrasonic waves to liquid metal, the alternate pressures may produce cavitation under certain conditions. Nevertheless, in order to produce cavitation, it is necessary to verify a wide range of conditions which depend not only on the ultrasonic parameters and the form in which they are transmitted to the medium but, also, of the physical characteristics and the level of impurities present in the melt. In addition to high degassing efficiency caused by the development of cavitation, the cavitation phenomenon also directly influences the solidification mechanisms.For this Special Issue, we wish to encouraged the submission of publications covering significant research developments by either ultrasonic melt processing of light alloys or the integration of ultrasonic equipment in the casting processes. It is expected that through such activities, any gaps that might exist between the conventional processing of light alloys and the ultrasonic melt processing technique will be effectively reduced or eliminated.

Dr. Hélder Puga
Guest Editor

Manuscript Submission Information

Manuscripts should be submitted online at www.mdpi.com by registering and logging in to this website. Once you are registered, click here to go to the submission form. Manuscripts can be submitted until the deadline. All submissions that pass pre-check are peer-reviewed. Accepted papers will be published continuously in the journal (as soon as accepted) and will be listed together on the special issue website. Research articles, review articles as well as short communications are invited. For planned papers, a title and short abstract (about 100 words) can be sent to the Editorial Office for announcement on this website.

Submitted manuscripts should not have been published previously, nor be under consideration for publication elsewhere (except conference proceedings papers). All manuscripts are thoroughly refereed through a single-blind peer-review process. A guide for authors and other relevant information for submission of manuscripts is available on the Instructions for Authors page. Metals is an international peer-reviewed open access monthly journal published by MDPI.

Please visit the Instructions for Authors page before submitting a manuscript. The Article Processing Charge (APC) for publication in this open access journal is 2600 CHF (Swiss Francs). Submitted papers should be well formatted and use good English. Authors may use MDPI's English editing service prior to publication or during author revisions.

Keywords

  • ultrasonic melt processing
  • light alloys
  • design and optimization
  • Al grain size
  • intermetallic phases
  • mechanical properties
  • acoustic cavitation
  • non-linear acoustics

Published Papers (3 papers)

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Research

14 pages, 3645 KiB  
Article
Multiphysics Modelling of Ultrasonic Melt Treatment in the Hot-Top and Launder during Direct-Chill Casting: Path to Indirect Microstructure Simulation
by Christopher Beckwith, Georgi Djambazov, Koulis Pericleous, Tungky Subroto, Dmitry G. Eskin, Dan Roberts, Ivan Skalicky and Iakovos Tzanakis
Metals 2021, 11(5), 674; https://doi.org/10.3390/met11050674 - 21 Apr 2021
Cited by 7 | Viewed by 2526
Abstract
This study concerns the numerical simulation of two competing ultrasonic treatment (UST) strategies for microstructure refinement in the direct-chill (DC) casting of aluminium alloys. In the first, more conventional, case, the sonotrode vibrating at 17.3 kHz is immersed in the hop-top to treat [...] Read more.
This study concerns the numerical simulation of two competing ultrasonic treatment (UST) strategies for microstructure refinement in the direct-chill (DC) casting of aluminium alloys. In the first, more conventional, case, the sonotrode vibrating at 17.3 kHz is immersed in the hop-top to treat the sump melt pool, in the second case, the sonotrode is inserted between baffles in the launder. It is known that microstructure refinement depends on the intensity of acoustic cavitation and the residence time of the treated fluid in the cavitation zone. The geometry, acoustic field intensity, induced flow velocities, and local temperature are factors which affect this treatment. The mathematical model developed in this work couples flow velocity, acoustics modified by cavitation, heat transfer, and solidification at the macroscale, with Lagrangian refiner particles, used to determine: (a) their residence time in the active zones, and (b) their eventual distribution in the sump as a function of the velocity field. This is the first attempt at using particle models as an efficient, though indirect, alternative to microstructure simulation, and the results indicate that UST in the launder, assisted with baffle separators, yields a more uniform distribution of refining particles, avoiding the strong acoustic streaming jet that, otherwise, accompanies hot-top treatment, and may lead to the strong segregation of refining particles. Experiments conducted in parallel to the numerical studies in this work appeared to support the results obtained in the simulation. Full article
(This article belongs to the Special Issue The Use of Ultrasonic Technology in the Treatment of Light Alloys)
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13 pages, 5405 KiB  
Article
Effect of Hybrid Ultrasonic and Mechanical Stirring on the Distribution of m-SiCp in A356 Alloy
by J. Grilo, H. Puga, V. H. Carneiro, S. D. Tohidi, F. V. Barbosa and J. C. Teixeira
Metals 2020, 10(5), 610; https://doi.org/10.3390/met10050610 - 8 May 2020
Cited by 5 | Viewed by 2708
Abstract
The present study details the micro-scale silicon carbide particle (m-SiCp) homogeneous distribution in an A356 alloy through hybrid ultrasonic-stirring melt treatment under different operation conditions. Ultrasonically excited fluids were studied by particle image velocimetry to estimate the efficiency of the acoustic streaming in [...] Read more.
The present study details the micro-scale silicon carbide particle (m-SiCp) homogeneous distribution in an A356 alloy through hybrid ultrasonic-stirring melt treatment under different operation conditions. Ultrasonically excited fluids were studied by particle image velocimetry to estimate the efficiency of the acoustic streaming in different distances to the sonotrode. Distinct particle approaches to introduce the melt and stirring techniques were performed to determine a successful route to promote a homogenous distribution of reinforcement particles. Results showed that the addition of m-SiCp in the semisolid state significantly improved particle wettability, preventing rapid sedimentation. The combination of ultrasonic induced streaming and mechanical stirring is an effective tool for the homogeneous distribution of m-SiCp along the casting specimen. Full article
(This article belongs to the Special Issue The Use of Ultrasonic Technology in the Treatment of Light Alloys)
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18 pages, 5738 KiB  
Article
A Novel Ultrasonic Cleaning Tank Developed by Harmonic Response Analysis and Computational Fluid Dynamics
by Worapol Tangsopa and Jatuporn Thongsri
Metals 2020, 10(3), 335; https://doi.org/10.3390/met10030335 - 3 Mar 2020
Cited by 18 | Viewed by 5529
Abstract
The manufacturer of an ultrasonic cleaning tank (UCT) received advise from a customer to seek the cause to why the UCT could not clean their products effectively and develop a novel UCT to replace the conventional model. This UCT had a capacity of [...] Read more.
The manufacturer of an ultrasonic cleaning tank (UCT) received advise from a customer to seek the cause to why the UCT could not clean their products effectively and develop a novel UCT to replace the conventional model. This UCT had a capacity of 10 L, a frequency of 28 kHz, four horn transducers, and a total power of 200 W. To resolve that problem and respond to customers’ needs, we presented new methods to develop the UCT using the harmonic response analysis (HRA) and computational fluid dynamics (CFD) to simulate the cleaning process which occurred within the UCT based on the actual conditions. Results from the HRA showed that the acoustic pressure in a problematic UCT was low, resulting in a smaller cleaning area, which was consistent with the results from the foil corrosion test, and thus caused the cleaning process to be ineffective. We developed a novel UCT with improved effectiveness by adjusting the design and adding a water circulation system. From the HRA, we were able to design the dimensions of the UTC and position of the transducer to be suitable to increase the acoustic pressure and cleaning area. CFD results enabled us to design proper inlet and outlet shapes, as well as simulate the water flow behavior to find the optimal cleaning condition so the novel UCT had a water circulation system that could eliminate the excess particles. Full article
(This article belongs to the Special Issue The Use of Ultrasonic Technology in the Treatment of Light Alloys)
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