Formation and growth of intermetallic compound at interface of steel/aluminum bonding sheet

Abstract

This paper deals with the formation and growth of intermetallic compound (IMC) at the interface of steel/aluminum bonding sheet. The bonding sheets were produced by hot rolling and diffusion bonding. The heating conditions which let to the formation of the IMC depended on the combinations of steel and aluminum sheets. The growth of the IMC layer was obeyed by parabolic law and the activation energy in the growth of the IMC layer were estimated to be 116 to 235kJ/mol. The growth rate of the IMC increased with the increase of magnesium content and the reduction of aluminum sheet. However, it decreased in case of using stainless steel sheet. The peel strength decreased with the increase of the IMC layer thickness (heating temperature) and the bonding sheets were peeled easily at the IMC/aluminum interface when the IMC layer thickness were more than 2μm. The IMC formed at the interface were FeAl3, Fe2Al5 and FeAl2.