Influence of pulsed laser processing conditions on dendrite tip radius

The correlation between laser processing conditions and microstructure of a solidified alloy is studied, namely, the dendrite growth during directional solidification of alloys induced by pulsed laser irradiation. A model including the thermal and solute diffusion processes as well as capillary effects at the solid/liquid interface is proposed. The dependence of dendrite tip radius on power density and pulse duration is obtained for relatively `softʹ regimes of laser processing, when evaporation and melt removal are negligible. The parameters of process conditions are found, when non-equilibrium conditions at the solid/liquid interface influence significantly the dendrite formation. The conditions when the dendrite growth is replaced by the planar one are determined.