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Research on microstructure in as-cast 7A55 aluminum alloy and its evolution during homogenization

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Abstract

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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Authors and Affiliations

  1. The School of Materials Science and Engineering, Harbin University of Science and Technology, Harbin, 150080, China

    Xinyu Lv & Erjun Guo

  2. Northeast light alloy Co., Ltd., Harbin, 150060, China

    Xinyu Lv & Guojun Wang

  3. State Key Laboratory of Nonferrous Metals and Processes, General Research Institute for Nonferrous Metals, Beijing, 100088, China

    Zhihui Li

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  1. Xinyu Lv
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  2. Erjun Guo
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  3. Zhihui Li
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  4. Guojun Wang
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Correspondence to Xinyu Lv.

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Lv, X., Guo, E., Li, Z. et al. Research on microstructure in as-cast 7A55 aluminum alloy and its evolution during homogenization. Rare Metals 30, 664–668 (2011). https://doi.org/10.1007/s12598-011-0446-7

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  • DOI: https://doi.org/10.1007/s12598-011-0446-7

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