Kenichi Hanazaki

Nanostructure Formation during Deep Wire-Drawing of Copper

It was confirmed in the present study that deep drawing process in multi passes to produce fine wires of copper alloys can act as a kind of severe plastic deformation process. High purity copper was deeply wire-drawn up to an equivalent strain of 6.9, and microstructure evolution and change in mechanical properties were investigated. It was confirmed that deep wire-drawing process produced nanostructures composed of fiber-shaped ultrafine grains with a diameter of about 300 nm. The copper wires having nanostructures showed tensile strength of 480MPa, which was two times higher than that of the starting material. The microstructures and mechanical properties of the deep drawn copper wire were almost equivalent with those of the copper sheets severely deformed by ARB process, though there were some minor differences between two processes.