Alloy Depletion 2

[coatingsguy]

I need to create some samples that exhibit alloy depletion in Ni-based superalloys. I've looked all over online and in my ASM Handbooks and can't find any general info on alloy depletion. I'm a metallurgist, so I know in general what it is. But I need more specifics if going to generate my own samples. Any input from some seasoned veterans out there?

 

[metengr]

coatingsguy;
Could you please explain exactly what you need in your OP? For example, is this for gas turbine blades or a Ni-base alloy component that experienced some type of corrosion resulting in a dealloying problem?

 

[coatingsguy]

Yes this is for gas turbine hardware. The only details I can give is that for our lab to receive a certain approval they must have alloy depletion samples in-house (possibly for training or reference material). So as the metallurgist on staff I've been given the task of producing these samples. I feel I only know enough to get me in trouble. I'm very detail oriented and want to be better educated on what alloy depletion is and what causes it before I move forward.

 

[metengr]

So as the metallurgist on staff I've been given the task of producing these samples.

So, you need to actually make coupons from various gas turbine blade alloys to demonstrate your lab's capability in recognizing the damage and to qualify a repair?

 

[coatingsguy]

Yes I need to actually create a sample that exhibits alloy depletion using a Ni-based superalloy material (Mar-M 247 for example if you're familiar with the more common ones)

 

[metengr]

coatingsguy;
We have a number of combustion turbines in our fleet. I would recommend that you purchase the following two books to really understand the metallurgy of Ni-base superalloys;

http://www.abebooks.com/products/is...ester-Thomas-Hagel-William-C/The-Superalloys/

http://www.wiley.com/WileyCDA/WileyTitle/productCd-0471011479.html

I had the company I work for purchase both of these excellent reference books to help me better understand the metallurgy, application and damage mechanisms of gas turbine blades.

 

[Helicopterjunky]

Coatingsguy,

I would think you could create samples of alloy depletion by running them in an oxidizing atmosphere at varying temperatures and times. Your sample is most likely using an etchant to microscopically detect an alloy depletion zone. Even certain vacuum furnace conditions could cause alloy depletion.

 

[coatingsguy]

Helicopterjunky,
Thanks for the input. I do have vacuum furnaces available to me. Do you have more details you can give on how to cause alloy depletion in vacuum? I prefer to use vacuum over oxidizing atmosphere.

 

[EdStainless]

The ones that I recall seeing were from cyclic oxidation testing in a burner rig. The depletion is not of the Ni, but the Cr, Al, Ti and other additions. Could you get some from one of the alloy houses such as Haynes?

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Plymouth Tube

 

[Helicopterjunky]

See the following link

http://www.industrialheating.com/Articles/Column/868a4b4478cb7010VgnVCM100000f932a8c0____