Interface Formation During Fusion™ Casting of AA3003/AA4045 Aluminum Alloy Ingots

Abstract

Fusionä casting is a unique Direct Chill continuous casting process whereby two different alloys can be cast simultaneously, producing a laminated ingot for rolling into clad sheet metal such as AA3003/AA4045 brazing sheet. Better understanding of the wetting and interface formation process during Fusionä casting is required to further improve process yields and also explore use of other alloy systems for new applications. In this research, AA3003-core/AA4045-clad ingots were cast using a well-instrumented lab-scale Fusionä casting system. As-cast Fusionä interfaces were examined metallurgically and by mechanical testing. Computational fluid dynamic analyses of the Fusion TM casts were also performed. It was shown that the liquid AA4045-clad alloy was able to successfully wet and create an oxide-free, metallurgical, and mechanically sound interface with the lightly oxidized AA3003-core shell material. Based on the results of this study, it is proposed that the bond formation process at the alloys interface during casting is a result of discrete penetration of AA4045 liquid at defects in the preexisting AA3003 oxide, dissolution of underlying AA3003 by liquid AA4045, and subsequent bridging between penetration sites. Spot exudation on the AA3003 chill cast surface due to remelting and inverse segregation may also improve the wetting and bonding process.

Case Study of a Functionally Graded Aluminum Part

“…Focusing on the combination FGM-automotive applications, and considering the high presence of the aluminum alloys in this sector [8], it is certainly possible to combine the aluminum alloys with the concept of FGM [9][10][11][12]. In fact, aluminum alloys are considered as very interesting materials, because of their lightweight, especially if compared with ferrous alloys, which lead to an important decrease in fuel consumption reducing the polluting emissions, and their high specific resistance and ductility [13,14].…”