Serious Education ... plus the most fun you can have in metal finishing.
Etching of Al5083 Aluminum Alloy
Q. I am a P.G. student in India and I am working on Al5083 alloy. I am having problems in getting optical microscopy. I tried different etchants (Kellers, Poultons and Bosserts) and electropolishing (5 ml HBF4 (48%)+200 ml Water) but I am not having success. I would like to know which is the best etchant and step by step procedure for this case? Thank you very much.Suraya Prakash Rao
a research scholar - Chennai, Tamil Nadu, India
A. As you have discovered, Keller's is not the best etchant for revealing grain boundaries in 5xxx alloys, especially those with more than 3% Mg. Barker's and Poulton's, though, should be able to show the general microstructure of 5083. Here are the correct procedures for using them:
Barker's - 5 mL HBF4 (48%) in 200 mL water. Specimen is the anode. Use Al, Pb, or stainless steel as the cathode. Anodize for 40-80 seconds at 0.2 A/cm^2, which is about 20 V dc. The microstructure should be viewed using polarized light. Sensitive tint filters also help.
Poulton's - 50 mL of Poulton's reagent (2 mL HF, 3 mL HCl, 20 mL HNO3, 175 mL water), 50 mL HNO3, 40 mL of solution of 3 g chromic acid per 10 mL water. Use a few drops on the surface for 1-4 minutes. If your sample is not developing well, use the maximum time. Rinse, then swab to remove the smut that develops. Microstructure should be viewed using polarized light, and the sensitive tint will help also.
Another option to consider is Weck's tint etching. It consists of 100 mL water, 4 g KMnO4, & 1 g NaOH. Again, the results are best when viewed using polarized light and sensitive tint filter. Anodizing the surface first may be useful.Toby Padfield
Automotive suspension modules - Michigan
+++++ -- this entry appended to this thread by editor in lieu of spawning a duplicative thread
Q. Hi my dear colleague;
I am studying on Al5083. and I could not see grain and boundaries. Can you help me? Otherwise I will leave this studying. I got bored studying this. I tried all solution but I could not see.
Please help me.
- Elazig, TURKEY
A. HI DEAR FRIEND
WE HAD YOUR PROBLEM ABOUT AL5083 (ABOUT ETCHANT FOR IT).
WE EXAMINED IT BY NAOH FOR 5-8 MINUTES AND WE COULD SEE METALLOGRAPHY IMAGES OF IT.
May 2, 2009
A. Hi friends.
I solved the problem. Firstly you heat test specimen and later etching. And than you can see grain and boundary.
May 26, 2011
A. Hi everybody
About etching 5083, I agree with Toby. You can use Barkers Reagent, Voltage 20V, 0.4 mA, 30-60 sec. If you use polarized light you will definitely see the grains with the clear, colorful and sharp area.
October 11, 2013
Q. PLEASE HELP ME IN FINDING THE CORRECT ETCHANT SO THAT IT CAN REVEAL THE GRAIN BOUNDARIES IN THE WELDED PLATE OF AA5052-H32BARLA MADHAVI
- HYDERABAD,ANDHRAPRADESH, INDIA
Hi Barla. There are many highly informative postings preceding yours. Please try your best to comment on their applicability to your situation, or to explain what you have tried and the difficulties you have encountered, so we can keep this discussion growing progressively deeper, rather than moving back from deep to shallow. Thanks!
Ted Mooney, P.E. RET
Pine Beach, New Jersey
Etching 2014 and 2xxx Aluminum Alloys++++
Q. I wish to etch 2014 aluminium alloy (90.4 - 95.0 Al, 3.9-5.0 Cu, 0.5-1.2 Si, 0.2-0.8 Mg Fe Mg Mn Ti Zn) to reveal the microstructure. Can anyone recommend a suitable etching solution (and preferably one that does not contain HF)?Gregory Gibbons
manufacturing group - COVENTRY, West Midlands, UK
A. I cannot find my reference book, but I find it amazing that your firm would have the mounting and polishing and microscope required for that evaluation and not have a book with solutions for the different things that you might need to be looking for, from grain size to grain boundaries to copper precipitation to ...?James Watts
- Navarre, Florida
A. Other than HF, two etchants that can be used successfully with copper-containing 2xxx series alloys are the following:
25 mL HNO3 (conc) + 75 mL H2O [Immerse at 70 °C for 45-60 seconds]
20 mL H2SO4 (conc) + 80 mL H2O [Immerse at 70 °C for 30 seconds, then rinse in cold H2O]Toby Padfield
Automotive module supplier - Michigan
Etching 6061 / SiC(2007)
Q. Hi. I have tested number of reagents including Keller's to see the grain boundaries in 6061/ SiC but fail. Please help me with what is best reagent for it.Imran Khan
student - Beijing, China
My name is Mike. I tried to do etching with Keller's reagent and 0.5% HF. I also tried electrochemical etching with 1.8% Hydroboro fluoric acid (fluoboric acid).
Can anyone please help me to etch the aluminum alloy (AA6061-T6)?
student - Sydney, NSW, Australia
Etching Al5456August 21, 2013
Q. Hi, I am trying to etch a new varient of Al 5456 (80% Al, 5% Mg, Mn, Cr, Fe,S i).
Kellers is not working, 0.5% HF is not working. Somebody please help me; I am very much worried.Johny Varghese
- Hyderabad, Andrapradesh, India
June 3, 2014
Q. Hello. I have a dissimilar joint of 5083-H12/6061-T6. I tried to etch this very much but I failed. Please tell me how can I do that.ahmad aziz
- tehran, iran
A. Hi Ahmad. Maybe a metallographer would understand your question better than I do, but I don't understand what you were trying to do, or what results you got :-(
Ted Mooney, P.E. RET
Pine Beach, New Jersey
June 4, 2014
Q. Hello. I have a dissimilar joint of 5083-H12/6061-T6. I want to figure out the grain size. How can i etch it?
Ed. note: Readers may also be interested in these threads:
letter 7041, "Etching Aluminum to Reveal Microstructure"
letter 55644, "Color Etching of Aluminum to Show Orientation of Grains"