INVESTIGATION OF THERMAL RESPONSE CAUSED BY PULSE LASER HEATING

Abstract

This article identifies models that are suitable for describing thermal transport in metal materials heated by a short-pulse laser. Three two-temperature models (dual-hyperbolic, hyperbolic, and parabolic), two one-temperature models (thermal wave and Fourier conduction), and one ultrafast thermomechanical model are investigated. A finite-difference method is used for solving the heat conduction equations, and a combined finite-difference/finite-element method is developed for solving the coupled thermomechanical equations. The numerical results, performed for gold films, suggest that for pure metals the hyperbolic two-temperature model be used for short-pulse (<1-ns) laser heating, while Fourier's law be used for long-pulse (>1-ns) laser heating. For alloys, the dual-hyperbolic two-temperature model is suggested for short-pulse (<10-ns) laser heating. Due to the high strain rate caused by nanosecond- and shorter-pulse lasers, a coupled thermomechanical model should be considered for more accurately predicting the lattice temperature field.