Microstructure and mechanical properties of Al-Zn-Mg-Cu (7075) alloy tubes prepared via power stagger spinning

The tubes of 7075 aluminum alloy were fabricated by power stagger spinning at 400 degrees C (HS) and room temperature (RTS), and then the microstructure evolution and mechanical properties were investigated. Results show that the grains after spinning are refined prominently, and the tubes after 60% and 70% thickness reduction (HS-60% and HS-70%) are dominated by the deformed structure, while the recrystallized structure is dominant in the tube after 85% thickness reduction at 400 degrees C (HS-85%). Furthermore, a bimodal grain structure with a weak Cube texture is obtained in the HS-85% sample due to the emergence of the dynamic recrystallization (DRX) and abnormal grain growth. As the thickness reduction increases from 0% to 85% during spinning at 400 degrees C, the yield strength (YS) and ultimate tensile strength (UTS) increase first and then decrease, while the elongation decreases first and then increases. Compared with that of the HS-85% sample, the UTS and YS of RTS-85% sample are 613.5 and 567.9 MPa, respectively, which are improved by 33.7% and 57.4%, while the elongation is only 7.3%.