Precipitation kinetics and structure of η precipitates in 7N01 aluminium alloy

ABSTRACT7N01 Al alloy is used extensively in high-speed train production. The mechanical properties of Al–Zn–Mg–Cu alloys are known to be closely related to the characteristics of their precipitates, which are greatly affected by the heat-treatment temperature. Herein, differential scanning calorimetry (DSC) and transmission electron microscopy (TEM) were used to investigate the precipitation kinetics and structure of η precipitates in 7N01 alloy. The solution temperature range of precipitation and the activation energy of η were determined using DSC analysis, and the chemical composition and crystal structure of the η precipitates were characterised using TEM. A relationship between the solution temperature and crystal structure was established, providing insight into the selection of the heat-treatment temperature for 7N01 alloy.