Abstract:The static recrystallization behavior of 7075 aluminum alloy containing Al₃(Sc,Zr) phase prepared by casting and the relationship between recrystallization behavior and mechanical properties were studied. The addition of Sc and Zr made the Sc-Zr-7075 aluminum alloy remain the most of fibrous structure and high-density dislocations formed in the extrusion process, resulting in the recrystallization fraction of the alloy decreasing from 35% to 22%, and the corresponding fraction of substructure increasing from 59% to 67%. The Sc and Zr effectively inhibited the recrystallization behavior of 7075 aluminum alloy mainly, which was attributed to the fact that the existence of fine and coherent Al₃(Sc,Zr) phase (r=35 nm, f=1.8×10^-3) strongly pined the dislocations and grain boundaries, preventing the dislocations from rearranging into sub-grain boundaries and from developing into high angle grain boundaries, and further hindering the formation and growth of recrystallized core of the alloy.

Key words: 7075 aluminum alloy; Al₃(Sc,Zr) phase; recrystallization; mechanical properties