Stress rupture cracks usually appear on turbine blades at which location?

• A. Root of Blade
• B. Casing
• C. Leading or Trailing Edge
• D. Between Blade and Rotor

Answer: (C)

Stress rupture in turbine blades happens when high temperature creep and tensile stresses act together for a long time. The places most prone to this are where heat transfer and mechanical stress create the strongest surface tension—the leading edge and the trailing edge. These edges face the hottest gas, large temperature gradients, and bending stresses that drive tensile loads on the surface, all of which promote creep crack initiation at or very near the surface. Small surface flaws, cooling-channel features, and film-cooling holes can concentrate stress there, accelerating crack start and growth under sustained high temperature.

In contrast, the root region, the casing, or the interface between blade and rotor experience different dominant failure mechanisms (fretting, mechanical fatigue, or contact issues) and don’t typically show the same edge-dominated creep crack behavior. That’s why the leading edge or trailing edge is the most common site for stress rupture cracks on turbine blades.