[Zurück]

B. Miesenberger, E. Kozeschnik, B. Milkereit, E. Povoden-Karadeniz:
"Computational simulation of precipitation during continuous cooling of 6xxx Al-alloys";
Poster: TMS Annual Meeting & Exhibition 2020, San Diego; 23.02.2020 - 27.02.2020.

Precipitation during cooling of alloys from an annealing temperature is strongly influenced by the cooling rate and directly affects the hardening response of the material.
The aim of the present study is the predictive understanding of cooling-rate dependence of precipitate evolution by physics-based thermokinetic simulation of heat flow curves based on Calphad thermodynamics, diffusion mobilities, nucleation theory and growth kinetics of precipitates, using the software package MatCalc. Al-Mg-Si alloys are studied, where main precipitates during cooling are β-Mg2Si and B´-Al4Mg9Si7. Experimental determination of their sizes and nucleation sites was done by scanning and transmission electron microscopy. Whereas the β-phase nucleates at grain boundaries, the B´-phase nucleation is associated with AlFeSi dispersoids. By combining these experimental findings with previous differential scanning calorimetry data, a suitable dataset for the validation of thermokinetic simulation is developed. Our simulation results go along with the experimental findings for various cooling rates