Dear Dr. Parisa Golmohammadi ,

I suggest you to have a look at the following documents:

-Metallography of Magnesium and its Alloys by George Vander Voort

Buehler Tech Notes

Available at: https://www.buehler.com/assets/solutions/technotes/vol4_issue2.pdf

-Visualization and Observation of Morphological Peculiarities of Twin Formation in Mg-Based Samples After Electrically Assisted Forming

Silvia Reschka, Gregory Gerstein, Andrej Dalinger, Sebastian Herbst, Florian Nürnberger & Stephan Zaefferer

Metallography, Microstructure, and Analysis: volume 8, pages806–814 (2019)

Available at: https://link.springer.com/article/10.1007/s13632-019-00589-2

-Metallographic Etchants Database by Pace Technologies

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

My best regards, Pierluigi Traverso.

Please consider the reason is that Mg2Ca phase is anodic relative to the Mg matrix incontrary with other phases in Mg alloys.

I personally used EBSD, because the grain boundaries were not etched using picral or nitral.

Dear Dr. Parisa Golmohammadi ,

I suggest you to have a look at the following documents:

-Metallography of Magnesium and its Alloys by George Vander Voort

Buehler Tech Notes

Available at: https://www.buehler.com/assets/solutions/technotes/vol4_issue2.pdf

-Visualization and Observation of Morphological Peculiarities of Twin Formation in Mg-Based Samples After Electrically Assisted Forming

Silvia Reschka, Gregory Gerstein, Andrej Dalinger, Sebastian Herbst, Florian Nürnberger & Stephan Zaefferer

Metallography, Microstructure, and Analysis: volume 8, pages806–814 (2019)

Available at: https://link.springer.com/article/10.1007/s13632-019-00589-2

-Metallographic Etchants Database by Pace Technologies

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

My best regards, Pierluigi Traverso.

Further information as below

http://www.steeldata.info/etch/demo/list/mg.html

The best etchant for Mg-Ca alloy is picral. As for Mg-based alloys the etching time is very important. The etching occurs within seconds (colour changes to reddish-brown). Hence to avoid over-etching, the sample must be immediately washed with ethanol.

Nitric acid based etchants are also used- but the micro-structure is not as good as that of picric acid based etchant.