Characteristics of hole formation during laser drilling of SiC reinforced aluminium metal matrix composites

The objective of this research is to investigate the hole formation mechanism during millisecond pulsed laser drilling of aluminium metal matrix composites reinforced with silicon carbide particles (Al MMC). The main focus of this paper is to provide an insight into the fundamental principles that govern the millisecond laser drilling of Al MMC, including the laser-material interaction and the subsequent melt ejection, so as to achieve a high quality and high-speed drilling process. The experimental results demonstrate that the laser drilling mechanism of SiC particle reinforced MMCs are different from the mechanisms observed in laser drilling of non-reinforced metals and alloys. High-speed videos and finite element analysis based models were used to study the mechanism of material removal. The SiC particles within the MMC are not melted and are ejected undamaged, along with the molten low melting point matrix materials, which makes the drilling process more efficient and enables drilling with a lower laser power compared to monolithic materials.