【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 ele
【机 构】
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The School of Materials Science and Engineering,Northeast light alloy Co.,State Key Laboratory of No
【基金项目】
：
the National Key Technologies R&D Program of China;国家自然科学基金
论文部分内容阅读
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℃ 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℃/72 h.
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