Laser short pulse heating of copper: Thermo–elasto–plastic analysis

Abstract

Laser short pulse heating of metallic substrates results in excessive electron temperatures in the surface vicinity. This gives rise to nonequilibrium energy transport in the region irradiated by a laser beam. Moreover, the thermomechanical coupling effect should be incorporated into the energy transport equation as lattice site temperature increases. In the present study, laser short pulse heating of copper is considered. The electron kinetic theory approach is employed to model the nonequilibrium heating process while thermomechanical coupling is introduced in the energy transport equation to account for the thermomechanical response of the substrate material. In order to determine the stress field, due to temperature gradient in the laser irradiated region, thermo–elastic and thermo–elasto–plastic analyses are carried out. Temperature and stress fields are computed numerically. It is found that temperature gradient is higher in the region next to the surface vicinity inside the substrate material. Equivalent stress levels attain high values in the vicinity of the surface which, in turn, results in a plastic zone in this region.