Effect of Zn content on microstructure evolution in Al-Zn alloys processed by high-pressure torsion

Al-Zn alloys having different Zn contents of 2, 5, 10 and 30 wt% were processed by high-pressure torsion (HPT) to produce ultrafine-grained (UFG) materials. Microstructural features of these UFG Al-Zn alloys were investigated using depth-sensing indentations, focused ion beam (FIB), scanning electron microscopy (SEM) and differential scanning calorimetry (DSC). Emphasis was placed on the microstructure evolution of the alloys with different Zn-concentration which demonstrated substantially different mechanical behavior, exhibiting superductility with increasing Zn content. It was shown that in every case, HPT resulted decomposition in the microstructure, but there is a significant difference between the microstructures of alloys with low and high Zn content. Based on the microstructural observations, a scenario is proposed about that how the decomposed microstructure developed during HPT process in low- and high Zn-containing Al-Zn alloys, influencing their mechanical behavior.

Automated summary

Al-Zn alloys with different Zn contents were processed by HPT to produce UFG materials. Microstructural features of the UFG Al-Zn alloys were studied using various techniques. The mechanical behavior of the alloys showed a substantial difference with increasing Zn content, and the microstructure evolved differently in low and high Zn-containing alloys during the HPT process.