Microstructure Evolution and Mechanical Properties Improvement of AlZnMgCu Alloys Induced by a Novel Double Electroshocking Treatment

Herein, a novel solution method of AlZnMgCu alloy using double electroshocking treatment (D‐EST) is proposed. Compared with the conventional solid solution treatment (SST) at 475 °C for 30 min, this method can provide more desirable results, although it only takes 10.2 s. Single tensile test results show that the ultimate strength and elongation after D‐EST followed by T6 aging are, respectively, increased by 2.6% and 6.8% relative to that of SST. In addition, the microstructure of the alloy after D‐EST and SST is characterized by the scanning electron microscopy, transmission electron microscopy, and electron backscattering diffraction (EBSD). The experimental results reveal that D‐EST can give rise to more adequate dissolution of secondary phases especially intermetallic compounds and long rod‐shaped dispersion phase, finer grains, and fewer grain boundaries in the range of 5°–8°. The kinetic mechanism of D‐EST is interpreted from the point of view of electromigration and the nonuniform distribution of temperature on the microscale.