Manufacturing of copper foams through accumulative roll bonding (ARB) process: structure and damping capacity behavior

Closed cell copper foams have been produced through accumulative roll bonding (ARB) using calcium carbonate (CaCO3) as blowing agent. Effects of temperature, time and number of rolling passes on the final porosity of the foam have been investigated. The foam with highest porosity has been achieved at 1100 degrees C for soaking time of 3 min. Structure of composite has also been studied by optical and electron microscopy. The result shows that increasing the number of rolling passes reduces the size of powder and homogeneously distributes the particles within the copper substrate. By reducing the size of the particles, free surfaces of particles increase and the gas releasing sites in the foams are enhanced. Consequently, the final porosity of the composite is enhanced as well. The closed-pore foams have also been examined by modal analysis. It has been found that higher porosity of the final foams results in higher natural frequency and damping index.