What type of metallurgical failure does Item A represent in the illustration? Illustration GT-0014

Correct Answer: Option B — Radial cracking.

Radial cracking, shown as Item A, propagates outward from the center or root towards the tip of the turbine blade. This failure is frequently caused by high-cycle fatigue or creep-rupture mechanisms, where centrifugal forces and thermal stresses exceed the material's yield strength, necessitating immediate engine inspection and component replacement.