Thermomechanical Interaction in Metal Films during Ultrashort Laser Heating

An ultrafast thermoelasticity based on a hyperbolic two-step heat conduction model with electron-phonon interaction is applied to investigate the thermomechanical response of five immense homogeneous, isotropic gold films (20 nm, 100 nm, 200 nm, 500 nm, and 2 m) impacted under femtosecond laser pulses by using finite element method (FEM). Finite element governing equations are established and solved in the time domain directly. The results, including electron temperature, lattice temperature, displacements, stresses, and strains, are presented graphically. The effect of thickness of thin films is studied; in addition, characteristics of stress evolution and displacement development in thin films are obtained. Finally, the influence of hot-electron blast force and thermal-mechanical coupling term are studied.