Microstructure Formation in Al-Bi-Co Immiscible Alloys Directionally Solidified with Different Melt Superheat Temperatures

Jie He , Chengyao Xing, Jiuzhou Zhao and Lei Zhao Institute of Metal Research, Chinese Academy of Sciences, Shenyang 110016, China

摘 要：The directional solidification has been carried out for the Al-4Bi-2.5Co （wt pct） alloys with different melt superheat temperatures. The microstructure characterization and the quantitative metallographic analysis have been performed. The results indicated that the Bi-rich sphere size and cellular spacing decrease with increasing melt superheat temperature. The interaction between the advancing solidification interface and the Bi-rich spheres with different sizes was analyzed. The effect of the melt superheat treatment on microstructure evolution was discussed for the immiscible alloys. The microstructure development in ternary Al-Bi-Co alloys directionally solidified with different melt superheat temperatures was clarified.

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