Microstructure and mechanical properties of dissimilar pure copper foil/1050 aluminium composites made with composite metal foil manufacturing

Abstract

In this paper, we present mechanical testing and microstructural analysis carried out on a number of layered composites of aluminium 1050 and pure copper foils. The parts were made by an additive manufacturing process termed as Composite Metal Foil Manufacturing. It is a combination of Laminated Object Manufacturing and brazing. The effectiveness of the process is validated with lap shear testing, peel testing, microstructural analysis and tensile testing. Joining dissimilar metals is generally difficult but the process is capable of achieving this goal with ease. Tests were carried out on lap joints with varying thickness to assess the effect on the bond. Tensile lap shear strength was also calculated using thicker plates by observing cohesion failure. The peel test showed a good bond consistency in all the specimens with an average peel strength of 20MPa. Microstructural analysis showed a large proportion of bonded area which is essential for proper bonding. Comparative tensile test was conducted among dog-bone specimens machined from solid aluminium 1050 block, copper block and composite Al/Cu specimen. The results showed that the specimen made by composite metal foil manufacturing fractured at a load value that is 11% higher than that of aluminium but lower than that of copper for the same overall thickness of the test specimens. This yielded a new composite that could be used for different applications based on its suitability.