Difference in the Hot Compressive Behavior and Processing Maps between the As-cast and Homogenized Al-Zn-Mg-Cu（7075） Alloys
来源期刊：JOURNAL OF MATERIALS SCIENCE TECHNOLOG2016年第7期
论文作者：S.Y.Park W.J.Kim
文章页码：660 - 670
摘 要：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 Zn2） 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.
S.Y.Park1,2，W.J.Kim1
1. Department of Materials Science and Engineering, Hongik University2. Advanced Fusion Process R&D Group, Korea Institute of Industrial Technology
摘 要：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 Zn2） 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.
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