Etching a weld AA6056 (AA4xxx filler wire)

[zbyhoo]

I have a big problem with finding an etchant for this:
AA6056 welded together (laser welding, AA4xxx filler wire).

I've tried many solutions, but still can't reveal the microstructure of the weld.
Any tips? Anybody had to deal with something similar?

 

[gariartola]

We work with cast parts and what we do is polishing down to 1 um diamond paste without etching. We can see the Si eutectic precipitate distribution and shape. Fe bearing phases will show clearly too.
We always check after T4 and T6.
Hope this is of any help!

 

[CoryPad]

I have used the following to etch alloy 6056:

immerse in NaOH solution (12 g in 100 ml H2O) for ~ 10 s

rinse with H2O

immerse in HF solution (2 % HF by volume in H2O) for ~ 10 s

I have no information on how a 4XXX alloy filler metal would respond.

 

[metengr]

You might want to try this web site. Search the archives for questions or send in your own specific question.

http://www.metallography.com/experts/search.html