Microstructural Characterization and Stress Corrosion Cracking Susceptibility of Al-Zn-Mg-Ti Alloys.

摘要

The effects of adding small amounts of titanium to age-hardening Al-Zn-Mg alloys have been studied by transmission electron microscopy,mechanical atests,and stress corrosion cracking (SCC) tests. The zinc,magnesium,and titanium content of the alloys was varied and the effect of aging upon these alloys was examined. Multiple stages of aging were observed for several of the titanium addition alloys. The resistance to SCC of the Al-Zn-Mg ternary in an aqueous solution (3.5% NaCl) at room temperature was significantly improved in the titanium addition alloy with 0.12% as compared to an alloy with 0.23% Ti reported upon previously. The addition of 0.09% Ti to Al-7% Zn-2% Mg alloy produces a finer grain boundary precipitation and no deleterious effect on the SCC property. (Author)