Microstructural and electrical properties of copper-titanium alloy dispersed with carbon nanotubes via powder metallurgy process

Abstract

Microstructural and electrical properties of copper alloy (Cu-Ti) with carbon nanotubes (CNTs) prepared by powder metallurgy (P/M) process have been investigated. The Cu-0.5mass%Ti pre-alloyed powder was made by water atomization process. The powders coated with un-bundled CNTs by using the zwitterionic surfactant solution containing CNTs were consolidated at 1223 K in vacuum by spark plasma sintering, and then extruded at 1073 K. The P/M Cu-Ti alloy without CNTs (monolithic alloy) had 202 MPa yield stress (YS) and 42.5 International-Anneld-Cupper-Standard % (IACS%) conductivity. The extruded Cu-Ti composite alloy containing CNTs revealed small decreased of YS compared to the monolithic Cu-Ti alloy. On the other hand, the composites revealed a higher electrical conductivity than that of the monolithic alloy. For example, Cu-Ti with 0.19mass%CNTs showed 175.8 MPa YS and 83.5 IACS% conductivity. In the case of the Cu-Ti composite with CNTs, intermetallic compounds such as Cu 4Ti and TiC were observed around CNTs by TEM-EDS analysis. The amount of the titanium solid solution in the above Cu-Ti composite alloy matrix was 10% of the monolithic Cu-Ti alloy, and resulted in the remarkable increment of its electrical conductivity.