高Zn組成Al–Zn–Mg系合金の水素脆化感受性に及ぼす水素侵入源の影響

抄録

Hydrogen embrittlement sensitivity (HES) of Al–Zn–Mg base alloys with high amount of zinc was studied by preparing the alloys without and with hydrogen charging. In order to clarify the effect of source of hydrogen entry on HES, we compared tensile properties between conventional strain rate testing (CSRT) in an ultrahigh vacuum atmosphere, and slow strain rate testing (SSRT) in a humid air atmosphere. It was clarified that the HES of the Al–Zn–Mg alloys varied depending on the source of hydrogen entry. Namely, internal hydrogen introduced during the melting and cast process lowers strength of the alloys. On the other hand, external hydrogen introduced from the alloy surface during SSRT under humid air raised the HES in the alloy with high strength. The HES caused by internal hydrogen was increased when the Al–Zn–Mg alloy contained high amount of hydrogen plus 0.1% of iron. The HES caused by external hydrogen was increased when the peak-aged Al–Zn–Mg alloy contained 0.1% of iron.