Strangeness Nimonic micro 1

[Liuk]

Hello,

Replica inspection of gas turbine blades was performed. I see some "strangeness" in micro structure. Please see attached (photo at 100x, photo at 500 in next message) Some precipitation along grains boundaries/in grains. Surface was cleaned carefully before replica...
Is it possible so coarse precipitation?

Thanks in advance

 

[Liuk]

And photo at 500x

 

[metengr]

In reviewing the 100x replica, the clusters of black spots look more like artifacts associated with pulling replicas. Overall, the replica quality is good, but having reviewed many replicas in the field, these appear to be from debris or other trapped particles in lieu of carbides or precipitates. The 500X replica shows possibly some phase but when you look closely it does not appear to entirely follow the grain boundary.