Al2O3 PARTICLE SIZE EFFECT ON REINFORCED CU COMPOSITES PRODUCED BY HIGH ENERGY MILLING

Production of copper (Cu) composites with a reinforced Cu matrix using mechanical alloying with Aluminum oxide (Al2O3) particles of different sizes was achieved using high-energy ball milling procedure. The initial materials consisted of inert gas-atomized spherical electrolytic Cu powders containing 0.5 wt. % commercial Al2O3 powders, with particle sizes ranging from 10 µm to 1 µm. Cu powders with different particle sizes of Al2O3 were high-energy ball milled at 500 rpm for 3 hours to attain a consistent distribution of Al2O3 throughout in the Cu matrix. The powders that were high-energy ball milled were then subjected to cold-pressing at 500 MPa and isothermally sintered for 1.5 hours at 880°C in an Ar atmosphere. The fabricated copper composite materials were characterized using X-ray diffraction analysis (XRD), field emission scanning electron microscopy (FE-SEM), energy-dispersive X-ray spectroscopy (EDXS), density and macrohardness tests. The wear properties and mechanism were investigated through tribological pin-on-disc experiments, which revealed that the reinforcing effect was more significant when finely dispersed Al2O3 particles were combined into the Cu matrix compared to coarse Al2O3 particles.