Characterization of AA5052-ZrO2 and AA5052-SiO2 surface composites fabricated by friction stir processing

Abstract

Friction stir processing is a surface modifying technique that allows microstructural modification and is being applied to control the behavior of a number of alloys. Surface composites of AA5052 alloy were fabricated by reinforcing zirconia (ZrO2) and silica (SiO2) particles by this process to improve the mechanical and corrosion properties. The developed surface composites of AA5052-ZrO2 and AA5052-SiO2 had a homogeneous distribution of particles with tensile strength equivalent to that of the base material. However, the hardness and corrosion behavior was different for both the composites. A significant improvement in microhardness was observed in the AA5052-ZrO2 surface composite while AA5052-SiO2 had microhardness similar to that of the base alloy. In the case of corrosion rate, AA5052-SiO2 had the least among the tested specimens while AA5052-ZrO2 showed no significant change. Fractography analysis and corrosion mechanism of the corroded specimens are also presented comprehensively.

Keywords

• aluminium alloys
• friction stir processing
• surface composite
• corrosion rate
• fractography