Electromagnetic Method to Control the Solidification of Al99.99
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JMEPEG https://doi.org/10.1007/s11665-019-03972-w
Electromagnetic Method to Control the Solidification of Al99.99 Marcela Pokusova´, Marta Murgasˇova´, Igor Berta, Maria´n Murgasˇ, and Alena Pribulova´ (Submitted September 30, 2018; in revised form January 9, 2019) The paper presents the electromagnetic method for control the solidification of the pure Al99.99%. For experiments, the treatments using (1) the flow of an alternating current of 500 A and (2) the simultaneous action of a DC magnetic field (0.035 or 0.07 T) and an alternating current of 500 A were applied. The ascast aluminum structure obtained under only an alternating current action was formed with the coarse crystallites being the shape of a plate with a thickness of 5 mm and a transverse dimension from 3 to 30 mm. The simultaneous action of a DC magnetic field and an alternating current resulted in grain refinement. Under a magnetic field of 0.035 T, the surface layer of the 0.8 mm thickness made up of the equiaxed grains with a size from 300 to 400 lm, and the targetÕs central zone formed with crystallites being of a size from 500 lm to 1.2 mm were observed. Under magnetic field of 0.07 T, the structure was formed with the fine equiaxed grains of 20-80 lm. The theoretical analysis was carried out to identify the processes involved in control of the solidification process of Al99.99 under the electromagnetic method. Keywords
Al99.99, alternating current, as-cast structure, DC magnetic field, electromagnetic force, solidification
1. Introduction In metallurgical practice, as well as the classic physicalmetallurgical methods of modification, inoculation, and microalloying (Ref 1-3), electromagnetic methods have been successfully introduced for controlling the process of primary crystallization (Ref 4). They offer more agents and mechanisms for operating, which show the different effects on the primary structure formed, when compared to those provided by the physical-metallurgical methods, or by the influence of mechanically generated forces (Ref 5, 6). Their current development focuses on application of physical fields as the electric current pulse (Ref 7, 8), the strong magnetic field up to 12 T (Ref 4, 9, 10), or the pulsed magnetic field (Ref 10, 11), which can generate forces of the high amplitudes. Another approach is demonstrated with the investigations (Ref 12-14) which showed that it is also useful to combine the classic metallurgical refining methods with the imposed external fields.
This article is an invited submission to JMEP selected from presentations at the 73rd World Foundry Congress and has been expanded from the original presentation. 73WFC was held in Krakow, Poland, September 23-27, 2018, and was organized by the World Foundry Organization and Polish FoundrymenÕs Association. Marcela Pokusova´, Marta Murgasˇova´, Igor Berta, and Maria´n Murgasˇ, Faculty of Mechanical Engineering, Slovak University of Technology in Bratislava, Na´m. slobody 17, Bratislava 812 31, Slovak Republic; and Alena Pribulova´, Faculty of Materials, Metallurgy and Recycling
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