Erosion ripple formation mechanism in aluminum and aluminum alloys

Abstract

The formation of ripples on pure Al and Al-12Si alloy surfaces was investigated. Sharp angular Al2O3 and spherical glass beads were used as erodent particles accelerated in an air-blast type system. The experimental variables were erodent particle shape, angle of impact, and abrasive particle mixture. Scanning electron and optical microscopy used to study the morphology of impacted surfaces showed the well-developed ripple formation on Al-12Si with beads used as abrasive. As the fraction of Al2O3 sharp particles mixed with glass beads was increased, the ripple formation on Al-12Si diminished. An investigation of the surface morphology of the eroded samples provided evidence for a mechanism of ripple formation based on material displacement instead of material removal.