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Lecture

WEB Modeling orowan strengthening in Al-Mg-Si Alloys

Friday (25.09.2020)
10:55 - 11:10 M: Modelling and Simulation 2
Part of:


The current study aims to computationally predict the strengthening at peak aging due to $ \beta'' $ precipitates from Orowan mechanism. The $ \beta'' $ precipitate properties (elastic constant and misfit strain) are characterized using first-principles DFT calculations. We build representative microstructures using experimentally-measured precipitate dimensions, and compute the stress field of the coherent precipitates using a novel Fast-Fourier Transform method. The stress field is then imported into a Discrete Dislocation Dynamics (DDD) model to simulate dislocation motion through the precipitate field. We compare critical resolved shear stresses (CRSS) calculated for periodic and random microstuctures, edge and screw dislocations, with and without precipitate misfit stresses, and including dislocation core energy effects. We find systematic effects due to each of the above, and use the full results to make a quantitative prediction of the strengthening for comparison to experiments.

Speaker:
Yi Hu
École Polytechnique Fédérale de Lausanne EPFL
Additional Authors:
  • Prof. Dr. W.A. Curtin
    EPFL