Abstract The microstructure evolution and composition distribution of as-cast and homogenized 2099 aluminumlithium （Al-Li） alloy were studied by optical microscopy （OM）, differential thermal analysis （DTA）, scan...Abstract The microstructure evolution and composition distribution of as-cast and homogenized 2099 aluminumlithium （Al-Li） alloy were studied by optical microscopy （OM）, differential thermal analysis （DTA）, scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS）, area and line scanning, X-ray diffraction （XRD）, and Vickers microhardness test methods. The results show that severe dendrite exists in the as-cast alloy. Cu, Zn, Mn, and Mg distribute unevenly from the grain boundary to inside. The low-melting point nonequilibrium eutectic phases dis- solve into the matrix during the first-step homogenization, whereas the melting point of residual eutectic phases is elevated. After the second-step homogenization, most of the remaining eutectic phases dissolve into the matrix, except a small amount of A1-Cu-Fe phases. An optimized homogenization process of the 2099 A1-Li alloy is developed （515℃ - 18 h ＋ 525℃ - 16 h）, which shows a good agreement with the homogenization kinetic analysis results.展开更多
基金financially supported by the National Key Basic Research Development Program of China(No.2012CB619504)
文摘Abstract The microstructure evolution and composition distribution of as-cast and homogenized 2099 aluminumlithium （Al-Li） alloy were studied by optical microscopy （OM）, differential thermal analysis （DTA）, scanning electron microscopy （SEM）, energy dispersive spectrometry （EDS）, area and line scanning, X-ray diffraction （XRD）, and Vickers microhardness test methods. The results show that severe dendrite exists in the as-cast alloy. Cu, Zn, Mn, and Mg distribute unevenly from the grain boundary to inside. The low-melting point nonequilibrium eutectic phases dis- solve into the matrix during the first-step homogenization, whereas the melting point of residual eutectic phases is elevated. After the second-step homogenization, most of the remaining eutectic phases dissolve into the matrix, except a small amount of A1-Cu-Fe phases. An optimized homogenization process of the 2099 A1-Li alloy is developed （515℃ - 18 h ＋ 525℃ - 16 h）, which shows a good agreement with the homogenization kinetic analysis results.
