Grain orientation and crystallographic texture governed gradient oxidation in laser peening

Abstract

This study examined the microstructural/crystallographic textural changes within a laser peened circular spot on Al-Li alloy 2060-T8 and their correlation with gradient oxidation. These changes were looked at the center and edge regions of the circular spot peened at 8 J and 13 J pulse energies. At the pulse energy of 13 J, grain orientation profoundly changed from 〈0 0 1〉 (base region) to 〈1 1 0〉 (laser spot) with reduced low coincidence site lattice boundaries at the edge of the laser spot. Ideal fibre texture was transformed into strong Cube {0 0 1} 〈1 0 0〉 and Goss {0 1 1} 〈1 0 0〉 textures respectively at 8 J and 13 J. Dense atomic structured 〈1 1 0〉 and 〈1 1 1〉 grain orientations and transformed strong Goss texture are observed to promote the oxidation significantly at the edge of laser spot for 13 J. Reasons for gradient oxidation within the laser peened spot were explained from the view point of microstructural/crystallographic textural changes.