Similarity in solidification mode between Fe-C and Al-Si alloys

Abstract

For the discussion of the formation of spherical graphite in Fe-C alloys, the solid/liquid interfacial morphology of Fe-C alloys was studied using a self-sealing UDS compared with Al-Si alloys. The influence of sulfur on the Fe-C alloys and strontium on the Al-Si alloys was investigated in order to discuss the change in the morphology of the eutectic graphite and silicon. The experimental results are as follows:

•	If the low sulfur Fe-C alloy contains cerium, the alloy solidifies as spheroidal graphite in the usual solidification. Nevertheless, the structure of the UDS sample is flake-like and identical with that of the 0.003 mass%S sample.
•	The graphite of the Fe-C-0.003 mass%S sample at the S/L interface is covered with the γ-Fe, but the graphite morphology is flake-like. The solidification rate becomes more than 4 mm/h, and the melt solidifies as undercooled graphite by the branching of the graphite.
•	These phenomena are identical with the effect of strontium in Al-Si samples.

Keywords:

• cast iron
• spheroidal graphite
• aluminum alloys
• modification of silicon
• interfacial energy