Amir Hossein Eslami - PhD student, Mechanical Engineering Dept., University of Birjand, Birjand, Iran
Hadi Hosseini - Instructor, Manufacturing group, Montazeri Technical University of Mashhad, Mashhad, Iran
S. M. Hossein Seyedkashi - Associate Prof., Mechanical Engineering Dept., University of Birjand, Birjand, Iran

Severe plastic deformation (SPD) is one of the methods of producing nano-scale grain size materials. To create a microstructure with relatively small grains, it is necessary to obtain high density of dislocations by application of high plastic strains. Multi-axial forging (MAF), RepetitiveCorrugation & Straightening (RCS) and Accumulative roll bonding (ARB) processes are several severe plastic deformation methods to achieve nano-structures. In the present research, commercial pure copper was processed with ARB, MAF and RCS processes in order to obtain ultrafine microstructure and improve its mechanical strength and hardness. After the preparation of the processed specimens using these three methods, structural and mechanical analyses were carried out at different stages of the process to investigate their properties. These experiments showed that the hardness, yield stress and ultimate tensile strength increased significantly by the increasing the number of pressing and rolling steps in allthree methods. The results also showed that the specimens produced by MAF method have better microstructural and mechanical characteristics than the ones produced by RCS and ARB

Accumulative roll bonding - Repetitive corrugation & straightening - Multi-axial forging - Pure copper.