Post-print of “HR Rahimi, M Sedighi, R Hashemi, (2018) Forming limit diagrams of fine-grained Al 5083 produced by equal channel angular rolling process, Proceedings of the Institution of Mechanical Engineers, Part L: Journal of Materials: Design and Applications, 232(11), 922–930. https://doi.org/10.1177/1464420716655560 1 Forming Limit Diagrams of Fine-Grained Al 5083 Produced by Equal Channel Angular Rolling Process H.R. Rahimi, M. Sedighi, R. Hashemi* School of Mechanical Engineering, Iran University of Science and Technology, Tehran, Iran *Corresponding author: e-mail: rhashemi@iust.ac.ir (R. Hashemi) Tel.: +98-21-77240540, Fax: +98-21-77240540 Abstract The objective of this research is to study the strain forming limits of Al-Mg alloy (5083) sheet, fabricated by equal channel angular rolling process (ECAR) at room temperature. For this purpose, the ECAR process was executed at room temperature in three passes. Mechanical properties, micro-hardness, and microstructure were investigated after the ECAR process. Uniaxial tensile tests of the ECAR process produced samples and showed that yield and ultimate stresses increase, while the uniform elongation to fracture decreases in comparison with the annealed state. There was a continuous hardness enhancement by increasing the number of the ECAR passes. After the third pass, the amount of hardness raised by 73% in comparison with the annealed sample. In the fourth pass, the hardness reduced slightly, that was attributed to the strain saturation in room temperature and was followed by high surface cracks. In the annealed condition, the average grain size was 45µm, and after the third ECAR pass, this amount was reduced to 10µm. Furthermore, the forming limit diagrams (FLDs) were determined experimentally, using the Nakazima test. The obtained results show that after the third pass, the