Combined Cyclic Deformation and Artificial Ageing of an Al-Mg-Si Alloy

Al-Mg-Si alloys exhibit a favorable combination of medium to high strength and processability by extrusion or forging. However, they can suffer from negative influence of natural ageing on subsequent artificial ageing and heat treatment times to achieve maximum strength can be quite long. Here we show that introducing a small plastic deformation step every ten minutes during artificial ageing of AA6060 at 160 °C reduces ageing time up to a factor of nine by periodic re-introduction of lattice defects, resulting in comparable yield strength yet slightly reduced ultimate tensile strength. A better understanding of the relationship between deformation and ageing can help to improve the efficiency of industrial processes, which are often characterized by alternation and combination of heat treatments and deformation steps.