M. Bournane¹, A. Berezina², О. Davydenko³, T. Monastyrska^2,, O. Molebny², V. Spuskanyuk³, A. Kotko²

The possibility of changing the structure and properties of the wrought low-alloyed, inexpensive Al-Mg-Si alloy due to the use of different modes of severe plastic deformation (SPD) in combination with different types of thermal treatments both before and after SPD has been studied. It was shown that the use of SPD at room temperature for Al-Mg-Si alloy formed a heterogeneous deformation structure which is characterized by incomplete dynamic recrystallization. The average grain size decreased from 200–500μm to 300–500nm. SPD provoked the deformation-induced complete or partial dissolution of excess phases, regardless of the initial state of the alloy. This was accompanied by the formation of a supersaturated solid solution in the matrix. Grain refinement and substructure formation led to the increase of tensile strength from 207 to 391 MPa in the pre-aged samples, their elongation being reduced by 30%. The study of aging and thermal stability of the structures formed after SPD showed that the SPD processes were accompanied by the formation of microporosity which determined the limits of the accumulated strain (∑e≤5.1) and the aging temperature (Т≤140°C).

6060 alloy, severe plastic deformation, hydrostatic extrusion, equal-channel angular hydroextrusion, aging, dynamic recrystallization