Corrosion and wear behavior of functionally graded Al2024/SiC composites produced by hot pressing and consolidation

Abstract

Functionally graded Al2024/SiC composites (FGMs) with varying percentage of SiC (30–60%) were produced by hot pressing and consolidation method. The effects of SiC content and number of layers of Al2024/SiC FGMs on the corrosion and wear behaviors were investigated. The microstructures of these composites were characterized by a scanning electron microscopy (SEM) with energy-dispersive X-ray spectroscopy (EDS). The corrosion performances of composites were evaluated by potentiodynamic polarization scans in 3.5% NaCl solution. Corrosion experiments shows that corrosion rate (1109mpy) of two layered FGMs which containing 50wt.% SiC were much higher than Al2024 matrix (2569mpy) and Al2024/50wt.% SiC composite (2201mpy). Mechanical properties of these composites were evaluated by microhardness measurements and ball-on-disk wear tests. As the applied load change from 15 to 20N, the wear rates of the Al2024 increased significantly and wear mechanism transformed from mild to severe wear regime. It has been shown that Al2024/40wt.% SiC composite has lower wear rate where adhesive and abrasive wear mechanisms play a major role.