Study on the Drilling of Titanium/Graphite Hybrid Composites

Titanium/graphite hybrid composites $(TiGr)$ are a potentially enabling technology which satisfies the low structural weight fraction and long operational lifetime required for the high-speed civil transport. $TiGr$ composites are made of thermoplastic polymer matrix composite plies with titanium foils as the outer plies. The two materials are assembled by bonding the polymer matrix composite plies and titanium foils to form a hybrid composite laminate. Both experimental and analytical work has been performed to characterize major hole quality parameters and cutting mechanisms encountered in drilling of $TiGr$ composites. The effects of consolidation processing, such as induction heating press and autoclave processes, on drilling characteristics of $TiGr$ composites were examined. The hole quality parameters and hole exit damage was investigated and discussed.