Material response to thermal loading due to short pulse laser heating

The laser-induced thermal stresses are important during heating of substrate surfaces, since stress levels above the yield stress of the substrate material occur. In this case, the plastic deformation and/or material defects occur in the irradiated region. In the present study, laser short pulse heating of gold is considered. The electron kinetic theory approach is employed to model the heating process. This approach accounts for the non-equilibrium energy transport in the surface vicinity of the substrate material. The thermal analysis and temperature predictions from an electron kinetic theory approach were presented in a previous study. Therefore, the results of thermo-elastic analysis due to the temperature field predicted in the previous study are given here. The elastic stresses developed in the substrate material due to the temperature field are modelled, and the temporal and spatial variations of the stress field and von Mises stresses are computed. It is found that the stress field in the substrate material does not follow the temperature field. A stress level on the order of 10⁹ Pa occurs in the surface vicinity.