1.9.1 Contents .................................................................................................................. 35 1.9.2 T4 temper stability of 6xxx series alloys (AlMgSi type) .......................................... 36 1.9.3 Effect of storage time on formability of 6xxx alloys ................................................. 37 1.9.4 Effect of storage time on paint bake response of 6xxx alloys ................................ 38 1.9.5 Over-ageing of 6xxx series alloys at elevated temperatures .................................. 39 1.9.6 Thermal stability of non-heated-treatable Al-alloys ................................................ 40 1.9.7 Thermal stability of 5xxx series alloys (AlMgMn) .......................................................................................................................................................................................................................................................................................................................