Computational modeling and experimental based parametric study of multi-track laser processing on alumina

In this work, both heat transfer modeling (COMSOL Multiphysics®) and experimental investigations were used to obtain the threshold multiple laser scanning processing parameters (laser power, scanning speed, fill space) for achieving more multi-faceted grains on the alumina's surface. An ytterbium doped Nd:YAG laser (1064 nm) was used to perform the experiments for the designed processing conditions such as 32–127×106 J/m2 laser energy densities with fill space values of 3–6×10−4 m. The SEM, EDX and wear results were used to quantify the effect of multiple laser processing variables on the change of microstructures (coarse grains, dendrite, multi-faceted grains) for obtaining the best processing conditions. By controlling the laser energy density with fill space, more multi-faceted grains and high wear resistance were achieved as the essential features for improving the abrasive quality.

► Fill space has more influenced on the formation of multi-faceted grains during multiple scanning of laser.
► As the cooling rate increased, the solidification rate increased which in turn generated more multi-faceted grains.
► A significant relationship existed between cooling rate, solidification rate, multi-faceted grains formation and wear rate.