Analysis of strengthening in AA6111 during the early stages of aging: Atom probe tomography and yield stress modelling

R. K.W. Marceau, A. de Vaucorbeil, G. Sha, S. P. Ringer, W. J. Poole

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In this work, a series of aging treatments has been conducted on AA6111 alloy samples for various times at ambient temperature (so-called natural aging) and at temperatures between 60 and 180 C (artificially aged). The time at artificial ageing was chosen such that samples with approximately the same yield stress were produced. The microstructures of these alloy samples have been carefully characterized using atom probe tomography together with advanced cluster-finding techniques in order to obtain quantitative information about the changes in distribution of both the solute clusters and early-stage precipitates that are formed. The size distribution of clusters has been mapped onto the glide plane and then the stress necessary for a dislocation to pass through the range of obstacles has been estimated using an areal glide model where the dislocation-obstacle interaction strength has been assumed to be related to the obstacle size on the glide plane. It is demonstrated that the contribution of cluster strengthening during artificial aging at higher temperatures is dominated by the high number density of small clusters (Guinier radius <1 nm), whereas the situation during room temperature natural aging is more complex.

Original languageEnglish
Pages (from-to)7285-7303
Number of pages19
JournalActa Materialia
Issue number19
Publication statusPublished - 1 Nov 2013
Externally publishedYes


  • Al-Mg-Si alloys
  • Atom probe tomography
  • Modelling
  • Solute clustering
  • Yield strength

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