Effect of single roll drive rolling on microstructure, texture, and mechanical property anisotropy of Al-5.6Zn-2.5Mg-1.4Cu aluminum alloy
(Department of Materials Engineering, Babol Noshirvani University of Technology, Shariati Ave., Babol 47148–71167, Iran)
Abstract: The current research aimed to study the microstructure and texture development of the Al-5.6Zn-2.5Mg- 1.4Cu alloy during single roll drive rolling process (SRDR). The relationship between mechanical property anisotropy and microstructure and texture was investigated in detail. The SRDR process was immediately performed on the solution-treated sample with four different thickness reductions of 10%, 20%, 40%, and 60%, respectively. Microstructural examination by optical and scanning electron microscopes, texture evaluation by X-ray diffraction, and mechanical properties evaluation by tensile tests were conducted. The results showed that the value of in-plane anisotropy was significantly reduced from 11.6% in solution-treated alloy to 2.4% and 3.1% in 40% and 60% reduction rolled samples, respectively. This was due to the formation of the Rotated Cube component, decreasing the overall texture intensity, and the formation of new grains through dynamic recrystallization. The yield strength in the rolling direction (RD) was higher than that in the transverse direction (TD), which was due to grain morphology and texture in these samples. The severity of Portevin-Le Chatelier (PLC) along the RD (0°) was much lower than that along the HD (45°) and TD (90°) owing to the presence of several strong orientations along the RD. By increasing the thickness reduction, the difference between strain hardening rates of RD, HD, and TD decreased due to the decrement of texture intensity. There was no difference between the fracture surfaces of 60% samples in the RD, HD, and TD, revealing nearly isotropic fracture behavior.
Key words: AA7075 aluminum alloy; single roll drive rolling; texture; mechanical properties; anisotropy