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The production of nanostructure materials or ultrafine grain (UFG) has been noticed by most of research society due to high strength, wear resistance, formability and high plastic strain rate. These features result from microstructure materials (100-300 nm) and unique defect (grain boundary-dislocation) make these material ideal for medical implant and structured components of aerospace and energy systems. The ways of producing UFG for these advanced engineering projects have not been considered yet. Due to the fact that nanostructured materials can show a good mechanical strength, researchers are using different ways to change pure copper into nanostructure one. One of these methods is applying process in equal channel angular pressing (ECAP), which coarse grain copper changed to nanostructure one. In this study, machinability of UFG as well as coarse grain (CG) copper is really considered in turning. To evaluate the machinability, cutting force, tool wear, chip morphology and surface roughness have been studied. Experimental results confirmed that UFG copper can be machined more efficiently than CG copper. In other words, the amount of BUE is reduced during turning ECAP copper due to the hardening of the pure sample. In comparison to CG copper, cutting force and surface roughness for UFG copper were less. As a result, machining performance can be improved partly by cold-work applying ECAP process. [ABSTRACT FROM AUTHOR]