Effect of grain size on the laser machinability of alumina

The effect of grain size on the laser machinability of alumina (Al₂O₃) was examined in order to meet the demand of higher tolerances when laser machining advanced ceramics. Laser lines created in alumina samples fabricated by using progressively increasing sintering times showed a difference in the amount of damage produced along the edges of the channels that were created, with less damage in smaller-grained samples. The average line width of the samples decreased with increasing grain size. It was hypothesized that these effects are a result of grain boundaries absorbing a higher amount of energy than the bulk.