Microstructure modifications induced by a laser surface treatment in an AA7449 aluminium alloy

This work investigates the modification of the precipitate microstructure induced by laser surface treatments in an AA7449 aluminium alloy in T7651 temper. Microhardness maps in the cross-section below the laser lines, as well as maps of the precipitate size and volume fraction obtained by Small-Angle X-ray Scattering, show that a significant precipitate dissolution and coarsening has been induced by the laser treatment. Integrated modelling is carried out to quantify this effect, including a thermal finite element model, a size class precipitation model and a precipitation hardening model. The precipitation model is calibrated using separate reversion experiments, and then coupled to the thermal and mechanical models, allowing a quantitative description of the modification of the microstructure.