رشد ترکیبات بین فلزی در ریخته گری مرکب دوفلزی مس و آلومینیوم

Formation of Intermetallic Phases in Al/Cu Compound Casting Process

بررسی رشد ترکیبات بین فلزی در ریخته گری مرکب دوفلزی مس و آلومینیوم

ABSTRACT

The purpose of this article is to study the growth rate of intermetallic compounds at the welded interface of Al/Cu bimetal were produced by compound casting process. The mechanism of the intermetallic compounds (IMCs) formations, the effects of aluminum pouring temperature and copper preheating temperature on the IMCs types and thickness were investigated and Al/Cu interface microstructure, were characterized by optical microscope (OM) and electron probe micro-analyzer (EPMA). Results show that the interface is consist of three main layers, the first Layer (I) is α-Al/Al2Cu eutectic structure, the second layer (II) is Al2Cu and the third layer (III) consists of the several intermetallic compounds such as AlCu, Al3Cu4, Al2Cu3, Al4Cu9. The first layer was formed by Al and Cu dissolving in liquid phase and rapid solidification, then the second layer II was formed by nucleation and growth mechanism at solid/liquid interface and finally the layer III was formed by solid-state phase diffusion. Raising the Al melt pouring temperature and preheating Cu leads to increase of the intermetallic compounds thickness at interface and consequently increases the specific electrical resistance and decreases the Al/Cu bond strength. From experiments, it is proposed that the bond strength is dominated by the thicknesses of layer II and III.