Direct measurements of liquid/solid interface kinetics during pulsed-laser-induced melting of aluminum

We report time-resolved electrical-resistance measurements obtained during pulsed-laser melting of a metal. Through heat-flow calculations and solute-diffusion measurements, the measured resistances are correlated with the thresholds for partial and full melting of a thin film of aluminum. Furthermore, simultaneous time-resolved reflectance measurements establish that, in this geometry, melting and solidification proceed via the motion of a well-defined, planar liquid/solid interface, whose position can be deduced from the resistance measurements. These measurements permit, for the first time, real-time determinations of melt-depth histories in fundamental studies of rapid solidification processing of metals