Microstructural evolution of Al-8.59Zn-2.00Mg-2.44Cu during homogenization
来源期刊：International Journal of Minerals Metallurgy and Materials2014年第12期
论文作者：Wen-xiang Shu Jun-cheng Liu Long-gang Hou Hua Cui Jun-tao Liu Ji-shan Zhang
文章页码：1215 - 1221
摘 要：The microstructural evolution and phase transformations of a high-alloyed Al–Zn–Mg–Cu alloy（Al–8.59Zn–2.00Mg–2.44 Cu, wt%） during homogenization were investigated. The results show that the as-cast microstructure mainly contains dendritic α（Al）, non-equilibrium eutectics（α（Al） + Mg（Zn,Al,Cu）2）, and the θ（Al2Cu） phase. Neither the T（Al2Mg3Zn3） phase nor the S（Al2Cu Mg） phase was found in the as-cast alloy. The calculated phase components according to the Scheil model are in agreement with experimental results. During homogenization at 460°C, all of the θ phase and most of the Mg（Zn,Al,Cu）2 phase were dissolved, whereas a portion of the Mg（Zn,Al,Cu）2 phase was transformed into the S phase. The type and amount of residual phases remaining after homogenization at 460°C for 168 h and by a two-step homogenization process conducted at 460°C for 24 h and 475°C for 24 h（460°C/24 h + 475°C/24 h） are in good accord with the calculated phase diagrams. It is concluded that the Al–8.59Zn–2.00Mg–2.44 Cu alloy can be homogenized adequately under the 460°C/24 h + 475°C/24 h treatment.
Wen-xiang Shu1，Jun-cheng Liu1，Long-gang Hou1，Hua Cui2，Jun-tao Liu1,3，Ji-shan Zhang1
1. State Key Laboratory for Advanced Metals and Materials, University of Science and Technology Beijing2. School of Materials Science and Engineering, University of Science and Technology Beijing3. State Key Laboratory for Fabrication and Processes of Nonferrous Metals, General Research Institute for Nonferrous Metals
摘 要：The microstructural evolution and phase transformations of a high-alloyed Al–Zn–Mg–Cu alloy（Al–8.59Zn–2.00Mg–2.44 Cu, wt%） during homogenization were investigated. The results show that the as-cast microstructure mainly contains dendritic α（Al）, non-equilibrium eutectics（α（Al） + Mg（Zn,Al,Cu）2）, and the θ（Al2Cu） phase. Neither the T（Al2Mg3Zn3） phase nor the S（Al2Cu Mg） phase was found in the as-cast alloy. The calculated phase components according to the Scheil model are in agreement with experimental results. During homogenization at 460°C, all of the θ phase and most of the Mg（Zn,Al,Cu）2 phase were dissolved, whereas a portion of the Mg（Zn,Al,Cu）2 phase was transformed into the S phase. The type and amount of residual phases remaining after homogenization at 460°C for 168 h and by a two-step homogenization process conducted at 460°C for 24 h and 475°C for 24 h（460°C/24 h + 475°C/24 h） are in good accord with the calculated phase diagrams. It is concluded that the Al–8.59Zn–2.00Mg–2.44 Cu alloy can be homogenized adequately under the 460°C/24 h + 475°C/24 h treatment.
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