The deformation mechanisms and processing maps of the as-castal-Zn-Mg-Cu （？0？5） aluminum （AI） alloy were studied and compared with those of the homogenized 7075 alalloy in the temperature range of 573-723 K an...
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The deformation mechanisms and processing maps of the as-castal-Zn-Mg-Cu （？0？5） aluminum （AI） alloy were studied and compared with those of the homogenized 7075 alalloy in the temperature range of 573-723 K and in the strain rate range of 10 3-10 s-1 to explore a possibility for directly using the as- cast 7075 alalloy as a billet for hot working. The as-cast and homogenized 7075 A1 alloys had similar grain sizes and showed similar high-temperature deformation behaviors. The as-cast 7075 alalloy, however, exhibited higher power efficiencies and smaller unstable flow regions compared to the homogenized 7075 AI alloy because of the presence of secondary phases （MgZn2） segregated at the dendritic interfaces in the as-cast microstructure, which were formed during non-equilibrium solidification. These segregated phases provided nucleation sites for dynamic recovery or continuous dynamic recrystallization, and as a result a fine and more homogeneous （sub）grain structure could be obtained from the as-cast micro- structure compared to the homogenized microstructure. The current work suggested the possibility and advantage of using as-cast microstructures for hot working of aluminum alloys with high content of solutes.
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