Precipitation Behavior of Fe-Al-O Inclusions under Unidirectional Solidification of Fe-30mass%Ni Alloys Saturated with CaO-Al₂O₃ Slags

抄録

The inclusions composition, size, morphology and distribution in an Fe-30mass%Ni alloy were studied as a function of the initial solute contents, which were controlled by the CaO-Al₂O₃ slags, and of the solidification parameters. The Al₂O₃-rich Al₂O₃-CaO inclusions were observed at the initial contents of Al=300-400 and O<6, while the FeO and the FeO-rich FeO-Al₂O₃ inclusions were observed at the initial contents of Al=2-6 and O=20-130 on mass ppm base. The FeO-rich FeO-Al₂O₃ inclusions were located in later stage of solidification in the intercellular or the interdendritic region. And most of the Al₂O₃-rich Al₂O₃-CaO inclusions were located in later stage of solidification, but some distributed in the intercellular or the interdendritic region. The dependence of the composition and the size of these inclusions on the cooling rate was not observed. The precipitation of FeO and Al₂O₃ was discussed by using the solute segregation models.