Fragmentation of CuO Oxides Caused by Various States of Stress Resulting from Extreme Plastic Deformation.

The development of microelectronics results in higher demand for copper microwires and thin foils. Higher demand requires conducting research to obtain knowledge on the influence of extreme plastic deformation on materials' susceptibility to plastic processing without the loss of coherence. One of the key factors contributing to rupture during the plastic deformation of copper is the presence of micrometer-sized, eutectic CuO oxides, which are weakly bound to the copper matrix. These oxides are formed during the metallurgical stage of wire rod copper manufacturing. Copper wire rod of the ETP (electrolytic tough pitch) grade was subjected to wire drawing followed by cold-rolling. Applying different states of stress during plastic deformation (wire drawing, cold-rolling, and upsetting) made it possible to specify the conditions required for CuO oxides' fragmentation due to the extreme total deformation. Qualitative and quantitative analyses of the CuO oxides' evolution and fragmentation as the plastic deformation progressed were the main focus of this paper. It was determined that major fragmentation occurred during the initial stages of plastic deformation. Applying further extreme deformation or changing the state of stress during plastic deformation did not facilitate the continuation of fragmentation. It was only their shape that was becoming elongated.