Information on the Operating Mode of Decomposition during the Cooling of an Al-10 at.% Zn Alloy to Various Tq

Information about the operating mode of decomposition during cooling to various T_q were gained by SAXS method. After reaching the T_q wanted the samples were quenched into water of RT and the SAXS intensity curves were measured at RT. Strong evidence was found that below about 175 °C the decomposition starts in this alloy with the nucleation and growth of Guinier-Preston zones. As proved by other authors, 175 °C is the upper limit temperature T_rhm for the onset of the rapid homogeneous nucleation of precipitates.