The solidification microstructure, grain boundary segregation of soluble arsenic, and characteristics of arsenic-rich phases were systematically investigated in Fe-As alloys with different arsenic contents and quenching temperatures. The results show that the solidifica- tion microstructures of Fe-0.5wt%As alloys consist of irregular ferrite, while the solidification microstructures of Fe-4wt% As and Fe-10wt%As alloys present the typical dendritic morphology, which becomes finer with increasing arsenic content and quenching temperature. In Fe-0.5wt%As alloys quenched from 1600 and 1200℃, the grain boundary segregation of arsenic is detected by transmission electron microscopy. In Fe-4wt%As and Fe-10wt%As alloys quenched from 1600 and 1420℃, a fully divorced eutectic morphology is observed, and the eutectic Fe2As phase distributes discontinuously in the interdendritic regions. In contrast, the eutecfic morphology of Fe-10wt%As alloy quenched from 1200℃ is fibrous and forms a continuous network structure. Furthermore, the area fraction of the eutectic Fe2As phase in Fe-4wt%As and Fe-10wt%As alloys increases with increasing arsenic content and decreasing quenching temperature.
Wen-bin XinBo SongChuan-gen HuangMing-ming SongGao-yang Song
