The Influence of Homogenisation Cooling Rate, Billet Preheating Temperature and Die Geometry on the T5- Properties for Three 6XXX Alloys Extruded under Industrial Conditions

The effect of processing and Mn content on the T5 and T6 properties of AA6082 profiles

“…Recrystallized bands are often seen on the periphery of extruded products and are associated with the high levels of stored strain energy near the product surface during hot extrusion [6][7][8]. The XRD analysis of the extruded profiles have shown the dominant intermetallic phase to be the cubic ␣-Al 12 (Mn, Fe) 3 Si in all three alloys (Fig. 3).…”

“…AA6082 uses an excess amount of silicon to increase age hardening response and an addition of manganese to control grain size [2]. The market increasingly demands improved performance in this alloy, particularly with regard to its strength, which is largely controlled by alloy chemistry and process parameters [3]. For high strength profiles, processing must be optimized to give either fine recrystallized grains or a uniform unrecrystallized structure.…”

Effect of cooling rate on precipitation during homogenization cooling in an excess silicon AlMgSi alloy

“…Higher extrusion temperatures are thus required leading to low productivity as the extrusion speed has to be reduced to avoid melting. Rapid cooling, on the other hand, traps the Mg and Si in solution with little or no Mg 2 Si precipitation [14][15][16]. So, the cooling rate has to be selected to precipitate as much Mg 2 Si as possible, with features that facilitate rapid dissolution during subsequent billet preheating [17].…”

The effect of homogenization practice on the microstructure of AA6063 billets

“…So, in contrast to soaking which is undertaken to achieve homogenization, the motivation behind controlled cooling is heterogenization [12]. Slow cooling tends to produce coarse Mg 2 Si particles while rapid cooling traps the Mg and Si in solution with little or no Mg 2 Si precipitation [13][14][15]. Coarse ␤-Mg 2 Si particles are difficult to solutionize at common preheating temperatures, resist solutionizing at high heating rates and may even survive the extrusion process.…”