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 irradiati on. A model including the thermal and solute diffusion processes as we ll 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 'soft' regimes of laser processing, when e vaporation and melt removal are negligible. The parameters of process conditions are found, when non-equilibrium conditions at the solid/liq uid interface influence significantly the dendrite formation. The cond itions when the dendrite growth is replaced by the planar one are dete rmined.