Processing and properties of Cu based micro- and nano-composites

Nano-composites of 1, 3, 5 and 7 vol% Al2O3 (average size <50 nm) and microcomposites having compositions 5, 10, 15, 20 vol% of Al2O3 (average size ∼10 μm) reinforced in copper matrix were fabricated by powder metallurgy route. All the specimens were sintered at different sintering temperatures (850, 900 and 1000 °C) to study the effect of temperature on the process and progress of sinterability of the reinforced micro- and nanoparticles in the matrix. These micro- and nano-composites were characterized using X-ray diffraction and scanning electron microscopy followed by density, microhardness and wear measurements. The compression and flexural tests were also carried out in order to investigate the mechanical behaviour of the micro- and nano-composites for a fixed optimum sintering temperature. Fractography of the 3-point bend specimens was performed to investigate the fracture behaviour of the micro- and nano-composites. The flexural test results showed that the ultimate flexural strength decreases and flexural modulus increases with the increase in reinforcement content.