A Review on the Machinability of Aerospace-Grade CFRP/Titanium Stacks

Multilayer stacks constituted by carbon fiber reinforced polymers (CFRPs) and titanium (Ti) alloys are advanced structural materials being extensively used in the modern aerospace industry in view of their superior properties and functionality. Prior to the final industrial applications, CFRP/Ti stacks have to be machined into desired shapes with qualified surface quality. However, these multilayer materials possess rather poor machinability due to the disparate natures of constituted phases. The present review aims to report on the recent advancements and achievements in the machining of CFRP/Ti stacks by emphasizing the key challenges and difficulties faced by the manufacturing community to achieve the high-quality drilling of the stack materials. A careful discussion on the machinability aspects of the aerospace-grade stacks in terms of chip separation mechanisms, cutting forces, machining temperatures and surface quality attributes was made following a detailed literature survey. T