Aluminium alloys of the 7xxx series are among those aluminum alloys that achieve the highest mechanical properties, they are achieved after aging, as they have the ability of precipitation hardening. As part of the diploma thesis, we investigated the influence of two programs of homogenization heat treatment on the formability of EN AW 7020 aluminium alloy during hot extrusion and the influence of homogenization on the subsequent heat treatment - artificial aging. After artificial aging, a tensile test was performed on the material, Brinel hardness was measured, and metallographic analysis was performed. We observed that the more homogeneous material already had recrystallized peripheral zone in the beginning after extrusion, ie. in the T1 state. Recrystallized zone negatively affected the mechanical properties of the profiles. An additional disadvantage was that the peripheral cone expanded during artificial aging at 135 °C, linearly with the aging time. The positive side of the more homogeneous alloy was that the precipitates after artificial aging were smaller and consequently better distributed along the αAl matrix, which resulted in higher mechanical properties. Tested homogenenized alloy exceeded the mechanical properties of the same time artificially aged standardly homogenized alloy. However, due to the expansion of the peripheral zone, the mechanical properties of the more homogeneous alloy later declined rapidly.
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