May 13 - 16, 2008
Billet Process and Equipment
Measurements and Modelling of Precipitation and Dissolution during Cooling and Preheating of Extrusion Billets
Børge Holme, Sylvain Gouttebroze, Calin Marioara --
SINTEF Materials and Chemistry, Norway
A semi-empirical mathematical model quantitatively predicts amount and sizes of Mg-Si containing phases in 6xxx alloy billets during cooling after homogenization (soaking), and during preheating prior to extrusion. Laboratory heat treatment experiments on AA6063 are reviewed, and extensively characterized using FEGSEM, TEM, and butanol dissolution, for tuning and verifying model predictions. Calculations shed light on microstructure evolution during billet cooling and preheating.