A Novel Approach for Fabrication of Cu-Al2O3 Surface Composites by Friction Stir Processing

In this study Copper- Al2O3 surface composites are produced with different volume percentages using micron sized particles via friction stir processing in order to enhance surface mechanical properties. Tool rotational speed and traverse speeds were fixed at 900 rpm and 40 mm/min respectively. The fabricated surface composites have been examined by optical microscope for dispersion of reinforcement particles and found that Al2O3 particles are uniformly dispersed in the stir zone. It is also observed that the microhardness at the higher volume percentage increases due to presence of hard Al2O3 particles. The tensile properties of the surface composites increased with the increase in the volume percentage of the Al2O3 particles. This is due to the addition of the reinforcement particles which increases the temperature of recrystallization by pinning of grain boundaries of the copper matrix and blocking the movement of the dislocations. The observed mechanical properties have been correlated with microstructure and fracture features.