Extension of the N-model to predict competing homogeneous and heterogeneous precipitation in Al-Sc alloys

• Published in: Acta materialia 2003-03, Vol.51 (5), p.1453-1468
• Main Authors: Robson, J.D., Jones, M.J., Prangnell, P.B.
• Format: Article
• Language: English
• Subjects: Aluminium alloys; Applied sciences; Coarsening; Cross-disciplinary physics: materials science; rheology; Exact sciences and technology; Materials science; Metals. Metallurgy; Modelling; Nucleation of phase transformations; Phase diagrams and microstructures developed by solidification and solid-solid phase transformations; Phase transformation kinetics; Physics; Precipitation; Solid-phase precipitation
• ISSN: 1359-6454; 1873-2453
• DOI: 10.1016/S1359-6454(02)00540-2

A model has been developed to predict the precipitation and coarsening kinetics of the Al 3Sc phase in Al-Sc alloys. This model is based on the N-model framework of Kampmann and Wagner (KWN), extended to account for competition between heterogeneous nucleation on dislocations and homogeneous nucleation. The predictions of the model have been tested against experimental data in the literature and also new experimental results, which are reported in this paper. Both the predicted particle size distributions and the evolution of particle size with time are in good agreement with the experimental data. The model correctly predicts the transition from homogeneous to heterogeneous domination of nucleation, as the ageing temperature is increased, and has been used to investigate the nucleation behaviour in detail. TTT diagrams for the precipitation of Al 3Sc have also been predicted for Al-Sc alloys.