A parametric study on laser drilling of Al/SiCp metal-matrix composite

Abstract

Machining of metal-matrix composites (MMCs) is difficult owing to their superior characteristics compared with the their parent materials. A specific application of modern laser technology is the drilling of cooling holes in aircraft engine ‘hot-end components’ such as combustion chambers, nozzle guide vanes, and turbine blades, which are made up of MMCs. Laser-drilled holes in aero-engine components must comply with strict quality standards that determine them suitable for in-service use. The current paper presents an effective approach for the optimization of neodymium–yttrium aluminium garnet (Nd:YAG) laser drilling of aluminium matrix/silicon carbide particulate (Al/SiCp) MMCs in regard to multiple characteristics, i.e. taper, spatter, and heat-affected zone (HAZ), based on response surface methodology and grey relational grades. Twenty runs based on the response surface methodology are performed to determine factorial interactions and decide the best factor level settings. In addition to response surface methodology, grey relational grades and desirability functions are used for multiple response optimizations. Laser drilling parameters such as pulse width and number of pulses, and MMC parameters like concentration of SiCp, are optimized with consideration to taper, spatter, and HAZ. By analysing the grey relational grade, optimal parametric settings for various responses are determined.