CHARACTERIZATION OF COMPOSITE MATERIAL (CLADDING OF COPPER-ALUMINIUM)
KODEM SURESH, DR.J.GOVARDHAN
Cladding, Copper-Aluminium, Composite material, Mechanical and Metallurgical properties.
Material obtained by combining two or more materials with various properties by metal working and fastening techniques such as riveting or by using nuts and bolts or by machining is called a composite. The entire work was performed to prepare a composite and to achieve its mechanical and metallurgical properties.
The preliminary work was to make using pure Al and pure Cu work pieces where the metal pieces were rolled till a 10% reduction in thickness were obtained. Later Cu roll was sandwiched between Al pieces on either sides and rolling has been performed, thus a composite material with same metals on either sides and other metal in between has been made. The reason for sandwiching Cu in Al on either side is that on exposure to environment, the atmospheric oxygen and other gases reacts with the outer metal and forms oxide. Since Al is on the surface, it forms aluminium oxide which is non-reactive and acts as a protective layer to the inner metal. Thus Al works like a sacrificial anode.
The purpose of making such a cladding is that, these types of cladded composites have wide range of applications. It is used for aerospace applications for fighter planes and satellites, used in submarines as the ship body has to be protected from the salt water and corrosive atmosphere. The Al on the outer surface continuously reacts with the salt and forms aluminium oxide which protects the inner Cu metal from getting oxidized and consumed. This type of composite has a wide range of application in defence for designing crucial components that get exposed to atmosphere.
The advantages of using a composite material instead of a metal piece alone are that a composite material reduces weight as two or more different metals of different physical properties are being used. Composite material increases the mechanical and metallurgical properties of the work.