Microstructural characterization and enhanced tensile and tribological properties of Cu–SiC nanocomposites developed by high-pressure torsion

Abstract

In this study, an attempt has been made to fabricate Cu–SiC nanocomposites by flake powder metallurgy and high-pressure torsion processing techniques at room temperature. Pure Cu and a mixture of Cu and nano-sized SiC powders were mechanically milled separately for 3 h and then green compacts were prepared by uniaxial pressing under 1 GPa pressure. The green compacts experienced 6-turn high-pressure torsion under a pressure of 6 GPa to prepare bulk Cu and Cu–SiC samples. The microstructures of the consolidated samples were characterized using an X-ray diffractometer and a high resolution scanning/transmission electron microscope, and the mechanical properties were evaluated by microhardness, tensile and wear tests. The results show that almost full density samples with ultrafine-grained (UFG) microstructure and well-dispersed nanoparticles in the metal matrix were obtained by the method used. The addition of the nanoparticles reduced the grain size and microstructural gradient between the center and edges of the disk samples. SiC nanoparticles improved copper microhardness by 35%, yield strength by 23% and tensile strength by 9% by implementing various strengthening mechanisms. The produced material showed a reduced coefficient of friction and high wear resistance. Delamination was determined as the major wear mechanism in HPTed Cu–SiC nanocomposite.