Topographic analysis of holes drilled by pulsed Nd:YAG laser on DD6 single-crystal superalloy

Abstract

Industrial applications of laser drilling include the production of cooling holes at vertical and acute angles in certain parts of the aero-engine components. Single-crystal nickel base superalloy turbine blades are being utilized in rocket engine turbopumps and turbine engines because of their superior creep, stress rupture, melt resistance, and thermomechanical fatigue capabilities over polycrystalline alloys. In this paper, laser drilling is used to manufacture cooling holes in DD6 single-crystal superalloy. Holes having diameters about 580 µ m were percussion drilled with a ND: YAG laser. Defects such as delamination, spatter and micro-crack formed during laser drilling process is investigated through a study of vertical and acute angle drilled holes. Topographies of holes in DD6 single-crystal superalloy by pulsed ND: YAG laser were analyzed. Recast layers, delamination, microcracks and spatters were found on the hole-walls. And the morphology of the recast layers, microcracks and spatters were clearly revealed by scanning electron microscope(SEM) in the present study.Industrial applications of laser drilling include the production of cooling holes at vertical and acute angles in certain parts of the aero-engine components. Single-crystal nickel base superalloy turbine blades are being utilized in rocket engine turbopumps and turbine engines because of their superior creep, stress rupture, melt resistance, and thermomechanical fatigue capabilities over polycrystalline alloys. In this paper, laser drilling is used to manufacture cooling holes in DD6 single-crystal superalloy. Holes having diameters about 580 µ m were percussion drilled with a ND: YAG laser. Defects such as delamination, spatter and micro-crack formed during laser drilling process is investigated through a study of vertical and acute angle drilled holes. Topographies of holes in DD6 single-crystal superalloy by pulsed ND: YAG laser were analyzed. Recast layers, delamination, microcracks and spatters were found on the hole-walls. And the morphology of the recast layers, microcracks and spatters were clear...