The microstructural evolution of 2026 aluminum alloy during homogenization treatment was investigated by optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray spectrometry (EDS), differential scanning calorimetry (DSC) and X-ray diffraction (XRD). The results show that severe dendritic segregation exists in the as-cast 2026 alloy and the main secondary phases at grain boundary are S (Al2CuMg) and θ (Al2Cu) phases. Elements Cu, Mg and Mn distribute unevenly from grain boundary to the inside of as-cast alloy. With the increase of homogenization temperature or the prolongation of holding time, the residual phases gradually dissolve into the matrix α(Al)and all the elements become more homogenized.According to the results of microstructural evolution,differential scanning calorimetry and X-ray diffraction, the optimum homogenization parameter is at 490 °C for 24 h, which is consistent with the result of homogenization kinetic analysis.%采用金相分析、扫描电镜、能谱分析、差示扫描量热法以及X射线衍射分析等手段,研究均匀化过程中2026铝合金微观组织的演变.结果表明:在2026合金铸态组织中,出现严重的枝晶偏析现象,晶界处的第二相主要是S相(Al2CuMg)和θ相(Al2Cu),元素Cu、Mg和Mn在晶内及晶界分布不均匀.在均匀化过程中,随着均匀化温度的升高或均匀化时间的延长,残留相逐渐溶入基体α (Al),元素分布逐渐均匀.综合考虑显微组织演变、差示扫描量热分析和X射线衍射分析等,最佳均匀化制度为490 °C,24 h,与均匀化动力学分析结果相符合.
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