Natural Aging of AlMg5Si2Mn Casting Alloy

Вікторія Володимирівна Бойко, Олена Леонідівна Прач, Олександр Іванович Трудоношин, Костянтин Вікторович Михаленков

Abstract


The as-cast and heat treated structure of permanent mould and high pressure die castings of the AlMg5Si2Mn alloy has been investigated by differential scanning calorimetry, microhardness measurements, transmission electron microscopy and energy dispersive X-ray analysis. Curved plate-like precipitates were detected for both alloys inside the α-Al grains. Examination of these precipitates revealed a number of features, such as: 1) the composition of the precipitates is very close to the stoichiometric Mg2Si compound; 2) precipitates are aligned along dislocations; 3) the precipitate density is much higher for the high pressure die castings where the α-Al matrix contains more dislocations than in permanent mould castings; 4) precipitates lie inside the α-Al grains where they are randomly distributed. The Mg2Si lamellas were not observed between precipitates; 5) homogenization of the alloy results in complete dissolution of the precipitates and during artificial aging new needle-shaped precipitates are formed.

Keywords


Aluminum casting alloy; Precipitates; Element distribution; Natural hardening

References


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DOI: https://doi.org/10.20535/1810-0546.2014.1.26582

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