Fractographic characterization of cracking in an aeroderivative gas turbine engine seal segment

Abstract An investment cast seal segment for an aeroderivative gas turbine engine was received at the authors’ laboratory in the grain-etched condition. The part exhibited a non-continuous surface crack in an area where there is a fin, with relatively sharp fillet radii on both sides. Both fillet radii were affected by the cracking. The cracking was caused by overload fracture from thermal stresses after solidification, in an area where casting microporosity coincided with geometric stress raisers.