Production of natural and synthesized aluminum-based composite materials with the aid of ultrasonic (cavitation) treatment of the melt

Éskin, G. I.; Eskin, D. G.

doi:10.1016/s1350-4177(02)00158-x

Cited by 189 publications

(85 citation statements)

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“…Their results suggested that ultrasonic vibrations cause a significant reduction in the apparent contact angle between the particles and melt. Eskin 118) demonstrated that ultrasonic treatment combined with electromagnetic stirring can provide an uniformed distribution of 5-7 mm SiC particles in a Al-0.4%Si-0.7%Mg-20%SiC composite. They also concluded that cavitation promotes the wetting of ceramic particles by liquid aluminum and involves them into solidification process.…”

Section: Al-base Alloysmentioning

confidence: 99%

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

2005

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In recent years, a large number of studies have been published on the use of high intensity ultrasonics in various high temperature technologies. This paper provides an overview of the recent achievements and ongoing works on the application of high intensity sound waves to pyrometallurgy and its related areas. The published results have strongly suggested that ultrasonics has the potential to play a more significant role in such areas as the dedusting of high-temperature exhaust gas, improvement of fuel-combustion efficiency, control of air-pollutant emissions, improvement of the quality of ingots, production of metal powders and ascast composite materials.At higher temperatures, special attractiveness of sound waves is associated with the fact that the waves can propagate through gas, liquids, and solids, and thus supply the acoustic energy from a cooled sonic generator to materials being processed under high temperature conditions. This provides a unique tool, for example, for controlling the rates of interfacial phenomena that is unachievable by any other methods under high temperatures.Industrial competitiveness of the ultrasonic-based technologies is reinforced by the relatively low cost of power-generating equipment and ultrasonic transducers. However, further research efforts are called for to develop new heat-resistant waveguide materials and to integrate the ultrasonic installations with existing industrial facilities in high temperature technologies.KEY WORDS: pyrometallurgy; high temperature; sonoprocessing; high power ultrasonics; non-linear phenomena; air pollutants; continuous casting; melt atomization; cast composites.applications have been summarized in a book by one of the authors of the present review. 4)The following two circumstances make ultrasonics especially applicable to high-temperature technologies: 1) There is a severely limited choice of techniques available for supplying energy under conditions involving higher temperatures. Among these techniques, sonic/ ultrasonic treatment or sonoprocessing should be competitive as regards both technique and cost, because it provides an effective transmission of acoustic energy from the ultrasonic generators to the materials being processed at a relatively low cost for ultrasonic equipment. 2) It is well-known that interfacial phenomena play an important role in governing many high-temperature processes. Examples are mass and heat transfer, crystal growth during the solidification of liquid metals, wetting, and emulsification. Sonic and ultrasonic waves propagate through homogeneous elastic mediums without significant losses. However, when the waves are incident upon an interface, the scattering or reflecting or of the waves from the interface is responsible for a number of nonlinear phenomena that occur at the interfaces. These provide a unique tool for controlling the rates of interfacial phenomena. Such a tool is unachievable by any other methods. Along with improvements in the earlier methods of sonoprocessing, a number of new ultrasonic appl...

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Section: Al-base Alloysmentioning

confidence: 99%

High Power Ultrasonics in Pyrometallurgy: Current Status and Recent Development

2005

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“…INTENSE vibration of the liquid metal during solidification is known to refine microstructure, remove trapped gas, and reduce porosity. [1][2][3] Vibration can be achieved through various means: shaking the crucible, inserting a mechanical stirrer in the melt or, more commonly, using an ultrasonic horn e.g., in the DC casting of aluminum ingots. [3] In ultrasonic processing, frequencies around 20 kHz were found to be the most effective, [3] a fact attributed to the onset of cavitation.…”

Section: Valdis Bojarevics Georgi S Djambazov and Koulis A Periclmentioning

confidence: 99%

“…[1][2][3] Vibration can be achieved through various means: shaking the crucible, inserting a mechanical stirrer in the melt or, more commonly, using an ultrasonic horn e.g., in the DC casting of aluminum ingots. [3] In ultrasonic processing, frequencies around 20 kHz were found to be the most effective, [3] a fact attributed to the onset of cavitation. Gas micro-bubbles exist in the liquid either due to dissolved gases coming out of solution as the melt cools (e.g.,H 2 in Al), air trapped with oxides during mold filling, or gas attached to the surface of immersed particles.…”

Section: Valdis Bojarevics Georgi S Djambazov and Koulis A Periclmentioning

confidence: 99%

“…Evidence of cavitation has been seen in situ recently, [4] found in postsolidification analyses and further shown to depend on a critical pressure threshold. [3] Of relevance to the present study, ultrasonic processing is one of the candidate techniques for the production of MMNCs.…”

Section: Valdis Bojarevics Georgi S Djambazov and Koulis A Periclmentioning

confidence: 99%

“…Vives [5] was the first to investigate experimentally such a non-contact technique, using a combination of static and AC magnetic fields. Other investigators followed this lead, used different configurations; for AlSi hypereutectic alloys, [3,6] for gray iron melts and aluminum alloys. [7] In each case, different thresholds of pressure amplitude were found to be necessary and a range of frequencies was used from 50 to 50 kHz.…”

Section: Valdis Bojarevics Georgi S Djambazov and Koulis A Periclmentioning

confidence: 99%

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