Mechanicaland thermal properties of the Al-Zn-Mg alloy with/without Sc,Zr-addition were investigated. The alloys were studied in the pseudohomogenized (460 °C/40 min), multistage (300 °C/60 min + 460 °C/40 min) and natural-aged state.
The distinct changes in microhardness curves and heat flow are caused by formation/dissolution of the Guiner-Preston zones and subsequent precipitation of the metastable η'-phase particles.