Delamination Induced by Laser Drilling on a Base Cobalt Superalloy

摘要

Temperatures in the high pressure chamber of aircraftengines are continuously increasing to improve theengine efficiency and constitutive materials need to bethermally protected. The first protection is a ceramicthermal barrier coating (TBC) cast on all the hot gasexposedstructure. The second protection is providedby a cool air layer realized by the use of a thousand ofdrills on the parts where a cool air is flowing through.The laser drilling process is used to realize these holesat acute angles on this coated mutlimaterial. Thepresent work aims at characterizing interfacialcracking induced by laser drilling on coated cobaltbase super alloy. This work attached to quantify thecrack by several microscopic observations with regardsto the most significant process parameters related asthe angle beam. The difference between thelaser/ceramic and the laser/substrate interaction is alsostudied with real time observation by using a fastmovie camera.