Effect of Heat Treatment on Microstructure and Properties of Al-7.0Zn-1.5Cu-1.5Mg-0.1Zr-0.1Ce Alloy

摘要

To obtain excellent properties in 7xxx series aluminum alloys, the heat treatment process used is an important factor. This needs to be chosen according to the different alloy compositions. A 7xxx series aluminum alloy with high zinc content (Zn/Mg > 4, Mg/Cu = 1) was prepared. Studying the heat treatment process of the alloy is important to guide companies in its industrial production. The optimum heat treatment process is explored from a microstructure point of view. The alloy was melted and cast in the laboratory using a metallurgical method. The microstructure, fracture morphology, and mechanical properties of the alloy were examined by metallographic microscopy, scanning electron microscopy, transmission electron microscopy (TEM), and tensile testing. Research on the alloy solution treatment was emphasized. The results showed that the solution effect was optimum at 470 degrees C x 1 h during a single-stage solution treatment. The recrystallization degree was low when the two-stage solution treatment process was 450 degrees C x 0.5 h + 475 degrees C x 0.5 h due to the release of deformation energy at low temperature; at the same time, the second-order solid-solution temperature was high, the solid-solution effect was better than in the single-stage solid-solution treatment, and the comprehensive mechanical properties of the alloy were better.