Precipitation strengthening of Al-Mg-Si alloy subjected to multiple accumulative roll bonding combined with a heat treatment

Thermo-mechanical treatment is one of the most important tools in designing properties of aluminum alloys. Plastic deformation introduces defects to microstructure and provides work hardening while a proper heat treatment may induce precipitation processes which lead to additional strengthening. In this work, a complex procedure is investigated with intention to increase mechanical strength of Al-Mg-Si alloy beyond conventional levels. Accumulative roll bonding is used as plastic deformation technique but with intention to provide a new microstructural feature - interlayer boundaries, instead of grain refinement. Solution heat treatment and ageing procedures are designed in a way that healing of the microstructure with maintaining some deformation-related features is maintained. Depending on the placement of solution treatment in the whole procedure, precipitation processes are similar or different from ones observed in a conventional solutionizing-ageing sequence. Nevertheless, the final hardness is always increased when compared to a typical heat treatment. Transmission electron microscope observations are performed to study variances in nucleation and growth of strengthening phases. (c) 2022 The Authors. Published by Elsevier Ltd. This is an open access article under the CC BY-NC-NDlicense (http://creativecommons.org/licenses/by-nc-nd/4.0/).