Microstructure investigation of a new type super high strength aluminum alloy at different heat-treated conditions
来源期刊：Rare Metals2004年第4期
论文作者：ZENG Yu, YIN Zhimin, ZHU Yuanzhi, and CUI Jianzhong College of Materials Science and Engineering, Central South University, Changsha , China;College of Metallurgy and Material, Northeastern University, Shenyang , China
文章页码：377 - 384
摘 要：<正>As a structural material with low density and high strength, super-high strength aluminum alloys have a future for wide application. However, its poor stress corrosion resistance （SCC） restricts further development. In present, retrogression and re-ageing （RRA） treatment, which can improve both strength and SCCR of 7XXX series alloy, is a best method to solve this problem. The effect of RRA treatment on the microstructure evolution of a new type low frequency electric-magnetic casting Al-9.0Zn-2.45Mg-2.2Cu-0.15Zr alloy was investigated using DSC and TEM technologies. The results show that the typical microstructure of the alloy at T6 condition is characterized by both fine η’ and GP zone homogeneously distributed in the matrix and continuous η particles occurred on the grain-boundary. After RRA treatment, the matrix precipitations are mainly fine and dispersed η’ and η phases, being coarser and more stable than that from T6 temper. While, the grain-boundary microstructure is very close to that result
ZENG Yu, YIN Zhimin, ZHU Yuanzhi, and CUI Jianzhong College of Materials Science and Engineering, Central South University, Changsha 410083, China;College of Metallurgy and Material, Northeastern University, Shenyang 110015, China
摘 要：<正>As a structural material with low density and high strength, super-high strength aluminum alloys have a future for wide application. However, its poor stress corrosion resistance （SCC） restricts further development. In present, retrogression and re-ageing （RRA） treatment, which can improve both strength and SCCR of 7XXX series alloy, is a best method to solve this problem. The effect of RRA treatment on the microstructure evolution of a new type low frequency electric-magnetic casting Al-9.0Zn-2.45Mg-2.2Cu-0.15Zr alloy was investigated using DSC and TEM technologies. The results show that the typical microstructure of the alloy at T6 condition is characterized by both fine η’ and GP zone homogeneously distributed in the matrix and continuous η particles occurred on the grain-boundary. After RRA treatment, the matrix precipitations are mainly fine and dispersed η’ and η phases, being coarser and more stable than that from T6 temper. While, the grain-boundary microstructure is very close to that result
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