Research on microstructure in as-cast 7A55 aluminum alloy and its evolution during homogenization
来源期刊：Rare Metals2011年第6期
论文作者：LV Xinyua, b, GUO Erjuna, LI Zhihuic, and WANG Guojunb a The School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin , China b Northeast light alloy Co., Ltd., Harbin , China c State Key Laboratory of Nonferrous Metals and Processes, General Research Institute for Nonferrous Metals, Beijing , China
文章页码：664 - 668
摘 要：The microstructure of the as-cast 7A55 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） analysis. The results indicate that the microstructure of the as-cast 7A55 aluminum alloy mainly consists of the dendritic network of aluminum solid solution, Al/AlZnMgCu eutectic phases, and intermetallic compounds MgZn2, Al2CuMg, Al7Cu2Fe, and Al23CuFe4. After homogenization at 470°C for 48 h, Al/AlZnMgCu eutectic phases are dissolved into the matrix, and a small amount of high melting-point secondary phases were formed, which results in an increasing of the starting melting temperature of 7A55 aluminum alloy. The high melting-point secondary phases were eliminated mostly when the homogenization time achieved to 72 h. Therefore, the reasonable homogenization heat treatment process for 7A55 aluminum alloy ingots was chosen as 470°C/72 h.
LV Xinyua, b, GUO Erjuna, LI Zhihuic, and WANG Guojunb a The School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin 150080, China b Northeast light alloy Co., Ltd., Harbin 150060, China c State Key Laboratory of Nonferrous Metals and Processes, General Research Institute for Nonferrous Metals, Beijing 100088, China
摘 要：The microstructure of the as-cast 7A55 aluminum alloy and its evolution during homogenization were investigated by means of optical microscopy （OM）, scanning electron microscopy （SEM）, energy dispersive spectroscopy （EDS）, X-ray diffraction （XRD）, and differential scanning calorimetry （DSC） analysis. The results indicate that the microstructure of the as-cast 7A55 aluminum alloy mainly consists of the dendritic network of aluminum solid solution, Al/AlZnMgCu eutectic phases, and intermetallic compounds MgZn2, Al2CuMg, Al7Cu2Fe, and Al23CuFe4. After homogenization at 470°C for 48 h, Al/AlZnMgCu eutectic phases are dissolved into the matrix, and a small amount of high melting-point secondary phases were formed, which results in an increasing of the starting melting temperature of 7A55 aluminum alloy. The high melting-point secondary phases were eliminated mostly when the homogenization time achieved to 72 h. Therefore, the reasonable homogenization heat treatment process for 7A55 aluminum alloy ingots was chosen as 470°C/72 h.
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