A model for the thermodynamics of and strengthening due to co-clusters in Al-Mg-Si-based alloys

Marco J Starink, Lingfei Cao, Paul Rometsch

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An expanded model for the thermodynamics of co-clusters and their strengthening is presented and applied to predict co-cluster formation and strengthening in Al–Mg–Si alloys. The models were tested against data on a wide range of Al–Mg–Si alloys aged at room temperature. The strengthening due to co-clusters is well predicted. The formation of co-clusters was studied in an Al–0.5 at.% Mg–1 at.% Si alloy using three-dimensional atom probe analysis. The results correspond well with the model. It is shown that in general (short-range) order strengthening due to co-clusters will be the main strengthening mechanism in these alloys. Apart from the co-clusters, Si clusters also form, but due to their low enthalpy of formation they contribute little to the strength.
Original languageEnglish
Pages (from-to)4194 - 4207
Number of pages14
JournalActa Materialia
Issue number10
Publication statusPublished - 2012

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