Surface microstructure and properties of Cu-C powder metallurgical alloy induced by high-current pulsed electron beam

This paper investigates the microstructure and properties of Cu-6C powder metallurgy (PM) alloys irradiated by high-current pulse electron beam (HCPEB). After 20-pulsed HCPEB irradiation, the surface was melted completely and the remelted layer was formed in 2-3 mu m thickness, which consisting of ultrafine Cu grains. Within the near irradiated surface, high-density dislocations and vacancy clusters were observed which provide a large amount of paths for carbon atoms to diffuse into Cu matrix, and it leads to the formation of the supersaturated solid solution, causing Cu lattice parameter expansion. In addition, the extreme rapid cycle generated the ultrafine carbon particles at the surface of Cu-6C metallic matrix. The results of microhardness measurements and sliding wear resistance testing indicated that the irradiated sample exhibited better properties than the initial one. The ultrafine carbon particles played an important role in the antifriction properties, which was attributed to the formation of carbonic tribolayer on the hard surface. (C) 2016 Elsevier B.V. All rights reserved.