Microstructural Evolution and Growth of Intermetallic Compounds at the Interface between Solid Cast Iron and Liquid Al–Si Alloy

Abstract

Compound casting has received a great deal of attention as a useful method for fabricating a single complicated part from dissimilar metallic materials. For example, in the case of automobile cylinder blocks, research is being carried out to compound cast iron with aluminum alloys. In order to manufacture such as composite parts, it is essential to control the intermetallic compound formed at the interface between two metals. In this research, the type and growth behavior of compounds formed at the interface between cast iron and aluminum, or Al–Si alloy, were investigated. It was observed that the Al5Fe2 phase was mainly formed at the interface between the pure aluminum melt and the solid cast iron, and the thickness of the interfacial compound increased proportionally with increasing contact time. On the other hand, more complex phases were formed at the interface between the Al–Si alloy melt and the solid cast iron. In the case of a specimen having a contact time of 10 min, Al4.5FeSi, Al8Fe2Si and Al5Fe2 phases appeared to occupy the largest portion of the interfacial compound region. The total thickness of the interfacial compounds also increased in proportion to the contact time.

Keywords

• compound casting
• intermetallic compound
• cast iron
• Al–Si alloy