In 6xxx-series alloys, there is a combined effect of deformation and ageing, creating higher yield and tensile strength due to strength contributions from dislocations and precipitates. It is difficult to separate the different contributions. To investigate the contribution from the dislocation, and how much dislocations are annihilated during the heat treatment, a 5xxx-series alloy was investigated.

In general, 5xxx-series alloys are considered to not have any effect of artificial ageing due to the low amount of Si available to create hardening precipitates. Deformation of the 5xxx-series alloy was performed at several different temperatures. After deformation, the alloy obtains a dislocation structure which increases the yield strength compared to the undeformed samples. The tensile strength is not changed.

The yield and tensile strength show only minor changes when solution heat treated and aged without any deformation. After deformation, the introduction of dislocations has likely increased the diffusion rate of the solute elements, leading to increased formation of hardening precipitates. These precipitates increase the yield and tensile strength of the alloy further above the purely deformed samples, giving a significant increase over the non-deformed samples.