INTERFACE MICROSTRUCTURE OF A DOUBLE-POURED AL/AL-5CU BIMETALLIC COMPOSITE

GUO WU; MARINA GALANO; KEYNA O' REILLY

Montreal

Congreso; THE 19TH INTERNATIONAL CONFERENCE ON COMPOSITE MATERIALS; 2013

Aluminium is a commonly used metal which has high strength to weigh ratio. With the development of automotive industry, there is an increasing need for lower energy consumption. The demand provides the drive for using lighter components based on Al. For a component made of a single material, it is very difficult to meet various requirements such as high strength at elevated temperatures, good corrosion resistance, low price, etc. Therefore, bimetallic composites consisting of two metals are being developed and a metal is usually bonded to a substrate using different processing methods, such as rolling bonding [1] and extrusion [2]. Components with sophisticated geometry may not be produced using the above approaches, as most of work which had been reported in literature so far only focus on the fabrication of bimetallic plates, rods, or other shape-limited products. One of the possible ways to produce bimetallic composites with complicated shapes is casting. It is noted that casting one metal on to or around the base metal allows more geometric flexibility of the final products and the use of casting may reduce industrial expenses and increase productivity. However, little work has been reported about this potential method. A major scientific interest for casting Al based bimetallic composites is the interface behaviour between two Al alloys. It is known that an oxide layer rapidly forms on the surface of Al in air [3]. The chemically and thermally stable oxide layer acts as a diffusion barrier. Metallic bonding may be achieved when the oxide layers have either been dissolved or disrupted between two metals. The work in this paper is to study the feasibility of casting an Al bimetallic composite and understand its interface microscopically. An approach termed as ?double-pouring? has been used to attempt casting an Al/Al-5wt.% copper (Al/Al-5Cu for simplicity) bimetallic composite and its interface microstructure has been characterized by means of metallographic, optical microscopy (OM), scanning electron microscopy (SEM), energy dispersive X-ray analysis (EDX).