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

Correct Answer: Option B — Axial cracking.

Axial cracking, as represented by Item B, typically occurs parallel to the longitudinal axis of the turbine blade. This failure mode is often associated with thermal fatigue or stress concentrations resulting from extreme temperature gradients during rapid start-up or shutdown cycles, requiring immediate inspection to prevent catastrophic blade liberation.