Effect of Al2O3 and SiC Nano Reinforcements on Microstructure, Mechanical and Wear Properties of Surface Nanocomposites Fabricated by Friction Stir Processing

摘要

In this study, friction stir processing has been applied to fabricate Al/Al2O3 and Al/SiC surface nanocomposites. Nano sized Al2O3, and SiC particles were used as a reinforcement whereas 6061-T6 aluminum alloy was selected as matrix material. The experiments were conducted at constant process parameters (1150?rpm and 15?mm/min) with changing volume percentage (2, 4 and 6) of nano reinforcements. The approach compared the effect of nano reinforcement on microstructural, mechanical, microhardness and wear properties of surface nanocomposites. Microstructure examinations revealed that Al2O3 and SiC nano particles were distributed into the processed region mainly in the form of clusters. Also, with increasing volume percentage of nano reinforcement increasing the defect formation. Vickers microhardness and tensile tests were conducted to study the mechanical properties of the surface nanocomposites. Superior microhardness properties were obtained along the stir zone. The addition of ceramic particle into the matrix material leads to increase in microhardness but simultaneously decreases yielding strength with an increase of wear resistance. The average coefficient of friction of Al/SiC composites were reduced than Al/Al2O3 composites. The effect of nano reinforcements on wear resistance was increased with increasing volume percentage of nano particles into the matrix material.