Dendritic Microstructure Affecting Mechanical Properties and Corrosion Resistance of an Al-9 wt% Si Alloy

Abstract

It has been reported that the mechanical properties and corrosion resistance of metallic alloys depend strongly on the solidification microstructural arrangement. The correlation of corrosion behavior and mechanical properties with microstructure parameters can be very useful for planning solidification conditions in order to achieve desired final properties. The aim of the present work is to investigate the influence of dendritic microstructural parameters of an Al-9 wt.% Si alloy on mechanical properties and corrosion resistance. The experimental results establish correlations between secondary dendrite arm spacings (λ₂) and ultimate tensile strength (σ _u ), yield strength (σ _y ), corrosion potential (E _Corr ), and corrosion rate (i _Corr ).

Keywords:

• Al-Si alloys
• Casting
• Chill mold
• Corrosion resistance
• Corrosion tests
• Dendrite arm spacing
• Electrochemical impedance spectroscopy (EIS)
• Equivalent circuit
• Mechanical properties
• Microstructure
• Polarization tests
• Solidification
• Tensile testing
• Ultimate tensile strength
• Yield strength

ACKNOWLEDGMENTS

The authors acknowledge financial support provided by FAEPEX-UNICAMP, FAPESP (The Scientific Research Foundation of the State of São Paulo, Brazil) and CNPq (The Brazilian Research Council).

Notes

∗P1 through P4 represent positions (increasing distance) from the metal/mold interface.