Abstract:Precipitation during the industrial cool down takes place predominantly above 300 °C in the EN AW-6082 and 6005 alloys. The phase precipitation throughout cooling is equilibrium b phase. A considerable capacity is retained after the cool down for further precipitation during a subsequent heating cycle. The b-Mg₂Si is once again the predominant phase that forms during a scan heating cycle employed in exactly the same manner with the industrial billet preheating operation. The precipitation in the 6060 alloy, on the other hand, occurs predominantly below 300 °C with additionally b′-Mg₂Si particles formed below 200 °C.

Key words: aluminium alloys; extrusion; precipitation; homogenization