The deformation mechanisms and processing maps of the as-cast Al-Zn-Mg-Cu(7075) aluminum(Al)alloy were studied and compared with those of the homogenized 7075 Al alloy 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 ascast 7075 Al alloy as a billet for hot working. The as-cast and homogenized 7075 Al alloys had similar grain sizes and showed similar high-temperature deformation behaviors. The as-cast 7075 Al alloy, however,exhibited higher power efficiencies and smaller unstable ?ow regions compared to the homogenized 7075 Al alloy because of the presence of secondary phases(Mg Zn_2) segregated at the dendritic interfaces in the as-cast microstructure, which were formed during non-equilibrium solidi?cation. These segregated phases provided nucleation sites for dynamic recovery or continuous dynamic recrystallization, and as a result a ?ne and more homogeneous(sub)grain structure could be obtained from the as-cast microstructure 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. The deformation mechanisms and processing maps of the as-cast Al-Zn-Mg-Cu (7075) aluminum (Al) alloy were studied and compared with those of the homogenized 7075 Al alloy in the temperature range of 573-723 K and in the The rate of range of 10 ~ (-3) -10 s ~ (-1) to explore a possibility for directly using the ascast 7075 Al alloy as a billet for hot working. The as-cast and homogenized 7075 Aloys similar similar sizes The as-cast 7075 Al alloy, however, showed higher power efficiencies and smaller unstable? ow regions compared to the homogenized 7075 Al alloy because of the presence of secondary phases (Mg Zn_2) segregated at the These segregated phases provide dynamic recovery or continuous dynamic recrystallization, and as a result a? ne and more homogeneous (grain) structure could be obtaine d from the as-cast microstructure 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.