Please use this identifier to cite or link to this item: http://hdl.handle.net/1822/50135

TitlePhysical modification of intermetallic phases in Al-Si-Cu alloys
Author(s)Barbosa, J.
Puga, Hélder
Oliveira, J.
Ribeiro, S.
Prokic, M.
KeywordsIntermetallic compounds
Solidification
Electron microscopy
Microstructure
Nucleation
Issue date15-Dec-2014
PublisherElsevier
JournalMaterials Chemistry and Physics
Abstract(s)The effect of applying ultrasonic vibration to the melt during cooling on grain structure, type and morphology of intermetallic compounds in AlSi9Cu3(Fe) alloy was studied, as well as their nucleation mechanism. Detailed intermetallics analysis was performed using a combination of SEM/EDS and XRD techniques in order to obtain the most possible reliable information. Results show that without ultrasonic treatment alpha-Al-17(Fe-3.2, Mn-0.8)Si-2, alpha-Al8Fe2Si, beta-Al9Fe2Si2 and Al2Cu are the intermetallic phases present in the as-cast samples. The application of ultrasonic vibration to the melt during cooling proved to be very effective in converting the alpha-intermetallics with Chinese script morphology to polyhedral crystals, suppressing at the same time the formation of the beta-phase. Moreover, the application of this treatment only changes the morphology of alpha-intermetallics since its stoichiometry remains the same (alpha-Al-17(Fe-3.2, Mn-0.8)Si-2). It was also verified that the application of acoustic energy to the melt promotes the change of alpha-Al grains from dendritic to a more globular structure. The ultrasonic treatment is also effective in promoting the fracture of polyhedral crystals of intermetallic phases, reducing their dimensions and causing their homogenous dispersion in the matrix.
TypeArticle
URIhttp://hdl.handle.net/1822/50135
DOI10.1016/j.matchemphys.2014.09.041
ISSN0254-0584
Peer-Reviewedyes
AccessOpen access
Appears in Collections:DEM - Artigos em revistas de circulação internacional com arbitragem científica

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