Microstructure and vacancy-type defects in high-pressure torsion deformed Al–Cu–Mg–Mn alloy

High-pressure torsion (HPT) was applied to the structural refinement of an age-hardenable Al–Cu–Mg–Mn alloy (AW 2017). HPT deformation gives rise to a fragmentation and dissolution of aging-induced precipitates and to a grain refinement down to sizes of 100 nm. Positron annihilation spectroscopy, in particular the chemical sensitive method of two-dimensional Doppler broadening spectroscopy, was used for a detailed analysis of the nature of vacancy-type defects induced by deformation and vacancy–solute interaction. The correlation between microstructure and atomic defects with thermal annealing is discussed.