Corrosion behaviour of Al/Al3Ti and Al/Al3Zr functionally graded materials produced by centrifugal solid-particle method: Influence of the intermetallics volume fraction

Intermetallic particles, Al3Ti and Al3Zr were formed in Al–5mass%Ti and Al–5mass%Zr alloys, respectively, by centrifugal casting, in order to create functionally graded materials (FGMs). At present, no information is available on the influence of the amount of intermetallics on the electrochemical properties of these alloys.In this paper, the corrosion resistance of Al/Al3Ti and Al/Al3Zr FGMs was investigated by open-circuit measurements, potentiodynamic polarization and electrochemical impedance spectroscopy. Results suggests that the corrosion resistance of the FGMs is affected by galvanic effects between the intermetallic particles and the metallic matrix. Lower centrifugal forces resulted in an improvement of the electrochemical properties.

Research highlights
► Corrosion resistance of Al/Al3Ti and Al/Al3Zr.
► The influence of the amount of intermetallic platelets on corrosion behaviour.
► Galvanic effects between the intermetallic compound particles and the metal matrix.
► A low segregation of particle leads to an improvement of the corrosion behaviour.
► FGM concept can be used to achieve trade-off mechanical and electrochemical properties.