Hydrogen Behavior in Al-Zn-Mg and Al-Cu-Mg Alloys Investigated by Means of Hydrogen Microprint Technique

Al-Zn-Mg and Al-Cu-Mg alloys have been known to be susceptible to stress corrosion cracking, which is based on intergranular fracture. The crack propagation mechanism depends on alloy system with cracking in the Al-Zn-Mg alloy resulting from hydrogen embrittlement. Hydrogen microprint technique, a method to visualize hydrogen atoms as silver particles on a specimen surface, was performed to investigate hydrogen evolution in Al-Zn-Mg and Al-Cu-Mg alloys during tensile deformation. Hydrogen was introduced into the specimens using hydrogen plasma gas. In Al-Zn-Mg alloy, silver particles were observed on some grain boundaries where a surface relief was formed. In Al-Cu-Mg alloy, silver particles were observed on the constituent particles as well as the grain boundaries.