The corrosion behavior of a particulate-reinforced metal-matrix composite (MMC) with an Al 6061-T6 (UNS A96061, Al-Mg-Si) matrix and 10 vol% alumina (Al2O3) particles was studied. The material was tested in different extrusion and forging conditions. Potentiodynamic polarization tests were carried out in aerated and deaerated sodium chloride (NaCl) solutions with concentrations from 0.06 N up to saturation to study pitting corrosion initiation. Three-month immersion tests were performed in aerated solutions. Results showed pitting corrosion initiated in aerated solutions, even for the lower chloride concentration. No significant influence of Al2O3 particles on corrosion susceptibility of the matrix was observed. However, corrosion attacks occurred preferentially in the vicinity of the reinforcing particles. Extrusion or forging treatment did not affect corrosion behavior of the composite material significantly.

Subject
Pits, Test methods, Immersion tests, Materials, Sodium chloride, Corrosion attacks, Sodium chloride solution, Composites, Salt concentration, Pitting, Immersion, Chlorides, Potentiodynamic polarization
Keywords:
Al 6061, alumina, aluminum, metal-matrix composites, particulates, pitting, potential, potentiodynamic polarization, sodium chloride
NACE International
1999
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