Pre-print of: G. Faraji, M. M. Mashhadi, Karen Abrinia & H. S. Kim (2012). Deformation behavior in the tubular channel angular pressing (TCAP) as a noble SPD method for cylindrical tubes. Applied Physics A: Materials Science and Processing. DOI: 10.1007/s00339-012-6809-6 1 Deformation behavior in the tubular channel angular pressing (TCAP) as a noble SPD method for cylindrical tubes G. Faraji a , M. M. Mashhadi a , K. Abrinia a , H. S. Kim b a Department of Mechanical Engineering, University College of Engineering, University of Tehran, Tehran, 11155-4563, Iran b Department of Materials science and Engineering, POSTECH, Pohang, 790-784, Korea Corresponding author; Email: ghfaraji@ut.ac.ir, Tel. /Fax: +982161114033 Abstract Tubular channel angular pressing is a recently developed technique for producing ultrafine grained and nanostructured tubular components. The current study dealt with the influence of the channel angles, friction coefficient and back pressure effect on the plastic deformation behavior and strain homogeneity in TCAP processing. The FEM results demonstrated that the equivalent plastic strains of 1.65-2.15, 2.15-2.85, and 2.5-3.75 have been achieved after applying one pass TCAP with channel angles of 120 º, 90 º, and 60º, respectively. Increasing the channel angle leads to lower equivalent plastic strain while obtaining better strain homogeneity. Strain homogeneity through the length of the processed tube is very good for all channel angles. Increasing the back pressure leads to slightly higher strain level while the strain homogeneity is decreased. Force results showed that lower loads were required for lower channel angles. It was also observed that for different values of coefficient of friction and channel angles, the load values converged to a constant value at the end of the process. Microstructural observations showed significant decrease in grain size from the initial value of ~150 μm to about 1 μm. Keywords: SPD; UFG materials; TCAP; Plastic behavior; Optical microscopy. 1. Introduction There has been a great deal of interest in recent years in improving material properties by grain refinements using severe plastic deformation (SPD) [1]. The most commonly used methods are equal channel angular pressing (ECAP) [2], high-pressure torsion (HPT) [3], and accumulative roll bonding