Improvement in Bake Hardening Response of Al-Si-Mg Alloys

Response to artificial ageing of dendritic and globular Al–7Si–Mg alloys

“…The additional signals superimposed on the DSC scan of alloy A when alloys B and C are thermally exposed, make their respective DSC scans look a lot like those of excess-Si wrought Al-Mg-Si alloys. The precipitation sequence of the latter is established to be, SSS → clusters → GP-I zones → ␤ → ␤ + Si → ␤ where SSS is the supersaturated aluminium solid solution [6,[16][17][18][19][20][21][22][23]. The precipitation sequence of alloys B and C is expected to be nearly the same possibly with a more pronounced Si precipitation activity.…”

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

“…8. The DSC spectrum of the EN AW 6082 sample quenched directly at the end of soaking reveals the full precipitation sequence owing to a supersaturated matrix, which is well established in AlMgSi alloys to be SSSS → GP zones→ β″ →β′ → Si → β [19][20][21][22][23][24][25][26][27]. Hence, the first weak exothermic signal centering at approximately 160°C is assigned to the formation of GP zones while the following weak endothermic signal to their dissolution.…”

Development of Al-Mg-Si-(Cu) Alloys for Automotive Body Panels and the Related Ageing Behaviours

“…Immediate high-temperature pre-ageing treatment. It is known that the detrimental effect of natural ageing can be reduced by using a proper pre-ageing treatment before artificial ageing [3][4][5][6]. One effective way is to apply very short pre-ageing times (seconds to a few minutes) at high temperatures (160-250 o C), which is of particular interests for a continuous production line.…”

“…The deleterious natural aging effect was accompanied by a coarser precipitate structure, which could be reduced by slowing down the ageing during storage by adding Cu or lowering the storage temperature. Different pre-aging treatments have been tried to avoid this adverse effect of natural ageing [3][4][5][6], in the sense that pre-ageing treatments can influence the artificial ageing response by changing the initial state of clustering or precipitation. Birol [5] investigated the pre-ageing treatment over a wide temperature range (60-250°C) for twin-roll cast 6016 sheet.…”