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MM: Fachverband Metall- und Materialphysik

MM 15: Poster session I

MM 15.14: Poster

Monday, March 7, 2016, 18:00–20:00, Poster B3

Atomistic simulation of the early stages of precipitation in Al-Si-Mg alloys — •Daniele Giofrè and Michele Ceriotti — Laboratory of Computational Science and Modelling - EPFL, Lausanne, Switerland

In the solid state the ternary phases exist mainly outside the fields of their primary crystallization. In the compositional range of 6XXX series alluminum alloys all phases, which form during the solidification, are of eutectic origin and are generally the result of non-equilibrium solidification (quenching mode). Furthermore, their properties are determined by the formation of coherent precipitates containing Mg, Al, Si.

In order to control the aging mode, namely the final result, an analysis of the stability and kinetics of these precipitates is of great importance in the Al-metallurgical industry. For these reasons it is particularly advantageous to have a mastery of the little-known early stages of precipitation. Therefore we want to study these small nuclei in order to investigate the aggregation of solute atoms, the critical sizes of nano-particules of the β″ phase, and their associated driving forces.

In the regime of this process, we have used a first-principles theory to conduct both the strength and stability study of the finite-size embedded precipitates nuclei of the β″ phase in the Al-bulk. We have carried out all that in order to compare the results with the simulation of formation energy, and to discover which is the morphology and stability of early precipitates and their thermodynamic driving force.