Effect of Spinning Deformation on Microstructure Evolution and Mechanical Properties of Al-Zn-Mg-Cu (7075) Alloy

In this study, the tubes of 7075 aluminum alloy were fabricated by power stagger forward spinning with different deformation (0%, 20%, 40% and 60%) at room temperature, then its microstructure evolution and mechanical properties were investigated. The results showed that the grains became significantly finer, the discrepancy of grain size along the radial direction (RD) is reduced and the recrystallized grains caused by continuous dynamic recrystallization (CDRX) were dominant in the microstructure after spinning deformation of 60%. The deformed texture produced by extrusion gradually dropped, the volume fraction of high-Schmid factor values (>0.4) descended first and then ascend with increasing deformation. In addition, the coarse secondary phases within the matrix were fragmented, but there is an incongruous movement between particles and matrix after spinning at room temperature. After the spinning deformation of 60%, the microhardness between 2.43 GPa and 2.49 GPa was significantly improved and was more uniform along the RD. Under 20% spinning deformation, the ultimate tensile strength (UTS) increased slightly and the elongation decreased significantly due to the extremely inhomogeneous microstructure along RD caused by the uneven deformation. With increasing the deformation to 60%, the maximum UTS (591.2 MPa) and yield strength (536.2 MPa) were obtained, which was mainly attributed to the combined effect of the improvement in deformation uniformity along RD, grain refinement and work hardening.