Replication. Cavities and carbides 1

[Liuk]

Hello,

Could you help me: what way is it possible to differ single creep cavity and hole from fallen carbide (at grains boundaries)? I have some doubt...

Thank you in advance.

 

[metengr]

I would recommend using an electropolishing method for surface replication. I found over the years this is the best approach to detect creep damage on in-service components in the field. The key is that creep cavities are round in shape and look like small bulls eyes or targets, whereas carbide or inclusion pullout is not round in shape.

 

[kclim]

Concur with metengr - shape, size are the two main features used to distinguish carbide pullout/creep cavities. You can sometimes use the distribution of the indications as a check, if you have good knowledge on how you expect creep damage to progress in your examined material.