You may get suitable etching as mentioned in the journsl article "Influence of the tool shape and weld configuration

on microstructure and mechanical properties of the

Al 6082 alloy FSW joints*. http://dx.doi.org/10.1016/j.acme.2014.02.001

1644-9665/# 2014 Politechnika Wrocławska. Published by Elsevier Urban & Partner Sp. z o.o.

Dear Metin Zeyveli ;

You can etch your sample with solution of; Methanol (25 ml) + HCl (25 ml) + HNO3 (25 ml) + HF (1 drop), for 10 to 60 sec.

http://www.metallographic.com/Etchants/Aluminum%20etchants.htm

Dear Metin Zeyveli

You can proceed with Keller's reagent i.e. Distilled water (95%)+ Nitric acid (2.5%) + Hydrochloric acid (1.5%) + Hydrofluoric acid (1%) to your polished specimen for 20 to 25 seconds.

Dear Dr. Metin Zeyveli ,

personally for Aluminum alloys, such as etching solution, I generally use Keller's solution, as suggested by Dr. Priyaranjan Samal , but in the following technical notes you can also try valid alternatives and specific characteristics.

-Metallographic Aluminum Etchants by Pace Technologies

Available at: https://www.metallographic.com/Metallographic-Etchants/Metallography-Aluminum-etchants.htm

-Metallographic preparation of aluminium and aluminium alloys by Struers

Available at: https://www.google.it/url?sa=t&rct=j&q=&esrc=s&source=web&cd=&ved=2ahUKEwjtqJmThuztAhUNGewKHRxaCHUQFjADegQIAxAC&url=https%3A%2F%2Fwww.struers.com%2F-%2Fmedia%2FStruers-media-library%2FMaterials%2FApplication-reports%2FAN-11_Aluminium_2015_ENG.pdf&usg=AOvVaw3ih5sXXOUyWS02X86zDYky

-Etching In Metallography by Kemet

Available at: https://www.kemet.co.uk/blog/metallography/etching-in-metallography

My best regards, Pierluigi Traverso.

Dear all, the general standard etching for aluminium alloy is Keller's solution as mentioned in the reference I suggested above, but specifically for this alloy, methanol solution was recommended as reported in the reference. With thanks.

@Pierluigi_Traverso

Dear Pierluigi,

I tried the keller solution but its not clearly wiev grain boundry for AA6082. But the keller solution is not fresh preparation. İs it effect the fresh or not.

I had tried the this solution but I used to HF (25ml) to total for %100. AA 6082 material etched but I think burn the some phase @Mahmood H. M.

You can try reduce the acid concentration

Dear Dr. Metin Zeyveli ,

it is certainly better to use an etching fresh solution and, if necessary, you can try to immerse a sample for a few five-ten of seconds more ... then eventually, depending on the result, set a standardized time for all your samples.

My best regards, Pierluigi Traverso.

Dear Metin Zeyveli

Yes , the freshness of some etching solution has a great effect. Also for electrolyte polishing special precautions are needed because of the existence of many phases such as Mg2Si , Al2Cu and Al6Mn

use Tucker's reagent etchant for aluminum 6082 : 25 ml of water, 15 ml HF, 25 ml HCl, 15 ml HNO3.

immerse or swabs of your specimen for 5 second.

Tkank you so much, Mr. Adnan