Numerical modeling of scanning laser-induced melting, vaporization and resolidification in metals subjected to time-dependent heat flux inputs

We present a 1-D heat transfer, melting, vaporization and resolidification model describing the interaction of a scanning continuous-wave laser with a metal surface wherein the beam power is rapidly time-varying. The effects of processing parameters on process variables for linear ramp and quadratic heat flux inputs are investigated numerically by varying beam diameters, scan speeds and substrate temperatures. Relations are derived for the times to initiate melting, to initiate vaporization, to reach maximum melting depth, for melting–resolidification, and for maximum melting and vaporization depths. Surface temperatures for both heat flux inputs are compared with approximate closed form solutions.