Nanoscaled structure of a Cu–Fe composite processed by high-pressure torsion

A Cu–Fe(10 vol.%) composite material was fabricated by the cold drawing process and then processed by high-pressure torsion (HPT). The resulting nanostructure was investigated by scanning electron microscopy, transmission electron microscopy and three-dimensional atom-probe analysis. This paper describes the fabrication of the Cu–Fe composite material and then the evolution of the microstructure during the HPT process. Experimental data reveal a strong decrease of the grain size in the range of 10–50 nm, which is much smaller than in pure iron or pure copper processed by HPT. A significant interdiffusion of Cu and Fe was also revealed by means of the atom-probe investigations. This mechanical alloying is discussed as a consequence of vacancies induced by severe plastic deformation.