Degradation mechanism of 6063 aluminium matrix composite reinforced with TiC and Al2O3 particles

Abstract

The degradation mechanism of 6063 aluminium matrix composites reinforced with TiC and Al2O3 particles was investigated by microstructure characterization, electrochemical experiments, scanning Kelvin probe force microscopy (SKPFM) and density function theory (DFT) calculation. The addition of the TiC and Al2O3 particles refines the grain structure of the composite material and increases the content of AlFeSi phase at the grain boundary. The surface Volta potential of AlFeSi (653 mV) was higher than that of the matrix alloy and Cl− is more easily adsorbed on the surface of AlFeSi phase rather than on TiC particles and AlMgSiCu phase. The strong absorption energy between Cl− and the AlFeSi phase will destroy the surrounding oxide film and cause the pitting corrosion around the AlSiFe phase. Therefore, the adding of TiC and Al2O3 particles reduces the corrosion resistance of the composite material.