Effect of ageing temperature on microstructure, mechanical property and corrosion behavior of aluminum alloy 7085

The influence of ageing temperatures on mechanical properties, corrosion behavior and precipitation features of aluminum alloy 7085 have been investigated by using tensile testing, intergranular corrosion tests, polarization curve measurements and transmission electron microscopy (TEM) observations. The results show that the precipitate sequence of aluminum alloy 7085 is different at different ageing temperatures. GP II is the main strengthening precipitate in the alloy peak aged at 90 °C, while η′ contributes most to the strength of the alloy peak aged at 150 °C. Similar ultimate yield strength can be obtained under either peak ageing conditions, but the work-hardenability at 90 °C is much better than that at 150 °C due to the predominance of GP II zones. Alloy 7085 peak aged at 150 °C shows better corrosion resistance than at 90 °C.