The interaction of molten copper with solid iron

Abstract

The interaction phenomenon of solid iron with molten copper was studied by investigating the interfacial microstructures of Cu/Fe and Cu-Ag/Fe and the migration mechanism of molten copper and Cu-Ag alloy into the solid iron. A small quantity of copper or Cu-Ag alloy was melted in a solid iron cylindrical specimen at temperatures ranging from 1100 to 1400° C using a high-frequency induction furnace. The Cu/Fe interfacial microstructure consisted of iron dendrites in the copper matrix, and an iron dendrite layer and a copper-penetrated solid solution zone adjacent to each other at the interface. Irrigation effects and grain-boundary penetration were observed partially at lower temperature. The addition of silver to molten copper causes inactivation of the reaction, resulting in the formation of thin reaction layers at the interface. The migration of molten copper and Cu-Ag alloy into solid iron occurs mainly with the formation of an iron-saturated layer due to iron dissolution and a copper-penetrated solid solution zone due to incipient volume diffusion. The copper penetration appears to be dominated by volume diffusion at high temperatures and by both volume and grain-boundary diffusion at low temperatures. Increased silver content in the molten copper decreases the penetration rate constant.