The corrosion behaviors of an as-forged AZ80 magnesium alloy after aging treatment for various durations at 170 °C were investigated by immersion test, H2 evolution test, SEM and potentiodynamic polarization curve measurement. The results show that the corrosion rate of the alloy decreases dramatically with the increase of aging time during the initial aging stage, but increases slowly with the aging time longer than 20 h. The volume fraction of β-Mg17Al12 increases with aging time within the first 20 h, leading to the decrease of corrosion rate. After aging for longer than 39 h, the growth of β phase is accompanied by the consumption of aluminum in the matrix, resulting in an increase in the corrosion rate. When the volume fraction of ？ phase is low, specimens suffer from severe local corrosion, which results in a porous surface. On the contrary, when the volume fraction of ？ phase is high, specimens suffer uniform corrosion attack.
The effects of pre-deformation following solution treatment on the microstructure and mechanical properties of aged high purity Al-Cu-Mg alloy were studied by tensile test, micro-hardness measurements, transmission electron microscopy and scanning electron microscopy. The micro-hardness measurements indicate that compared with un-deformed samples, the peak hardness is increased and the time to reach peak hardness is reduced with increasing pre-strain. Additionally, a double-peak hardness evolution behavior of cold-rolled （CR） samples was observed during aging. The results of TEM observation show that the number density of S′（Al2CuMg） phase is increased and the size is decreased in CR alloy with increase of pre-strain. The peak hardness and peak strength of the CR alloy are increased because of quantity increasing and refinement of S′ phase and high density dislocation.
