Abstract
This investigation was perfomed in order to understand the influence of heat treating conditions and minor additional elements on the exfoliation characteristics of commercial Al-Zn-Mg alloys. The results obtained are as follows:
(1) In a commercial Al-4.2%Zn-1.36%Mg alloy, exfoliation sensitivity increased with decrease of solution treatment temperature and aging temperature. As precipitation proceeds, exfoliation sensitivity decreased. In an experimental Al-4.5%Zn-1.2%Mg alloy, addition of a small amount of titanium, chromium or zirconium increased it's exfoliation sensitivity.
(2) From microscopic observation of the exfoliated specimens, it was considered necessary for exfoliation of Al-Zn-Mg alloys that compounds of the minor additional elements existed in a lamellar state.
