🔍 Key Concepts

• Look at the orientation of the crack at Item A compared to the long axis (root-to-tip) of the turbine blade. • Understand the difference between axial and radial directions on a rotating part like a turbine blade. • Know that rupture and creep describe overall material failure mechanisms over time, while cracking choices describe the direction of visible cracks.

💭 Think About

• Does the crack at Item A mostly follow the length of the blade, or does it mainly cut across it toward the leading/trailing edge or root? • On a rotating blade, which direction is called axial and which is called radial—and which term would you use for a crack that runs generally parallel to the blade’s span? • If a part had creep or rupture, what would you expect the overall damage to look like, compared with a clearly defined, oriented crack like the one at Item A?

✅ Before You Answer

• Identify the primary direction of the crack at Item A (parallel to the blade’s long axis or crossing it). • Match that direction to the correct term: axial = along the axis/length, radial = outward from the center of rotation/across the section. • Confirm that creep and rupture describe long‑term deformation or complete failure, not simply the geometric orientation of a crack.