An analysis of cooling rate influence on the sequence of intermetallic phases precipitation in some commercial aluminium alloys

Abstract

In the present work the evolution of the morphology (examined by means of SEM) and changes in the chemical composition (examined by means of EDS microanalysis) of the intermetallic phases precipitates, containing Fe and Mn, in AA3004 type alloy, slowly cooled and frozen at 580, 510 and 430 °C, was analysed. The morphology of the intermetallic phase particles, depending on their chemical composition and precipitation temperature, was determined. It has been stated that intermetallic phases Al₆FeMn and α-Al(FeMn)Si, of different stoichiometry, precipitate at successive stages of solidification and cooling. The α-Al(FeMn)Si phase particles chinese script (Fe/Mn=2.3, [Fe+Mn]/Si=2.1-2.5) and branches (Fe/Mn=2.7-3.1, [Fe+Mn]/Si=2.3) were observed.

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