Purpose: reveal the microstrucrure of a 2xxx series of aluminum-copper alloy
Method: use the Keller's reagent to reveal the grain structure and the precipitation
Etchant: (Keller's reagent)
2ml HF (48%)
3ml HCl
5ml HNO3
190ml H2O;
Etching Procedure:
immersion/swab for 10 - 20 sec.