Fabrication and mechanical properties of WC nanoparticle dispersion-strengthened copper

Abstract

Cu composites strengthened through carbide nanoparticle dispersions (CDS–Cu) usually present a problematic agglomeration of nanoparticles that deteriorate their mechanical properties. To address this issue, in this study, CDS–Cu composites were prepared via spark plasma sintering (SPS) of reduced Cu-coated WC core–shell precursor powders, which were obtained through intermittent electrodeposition. This novel preparation method overcomes the aggregation problem of tungsten carbide (WC) nanoparticles, thereby improving the interface-bonding strength between the reinforcing-phase WC nanoparticles and the Cu matrix and further enhancing the load-transfer efficiency. The yield strength of the Cu-2.1 wt% WC composite prepared via pressureless sintering is up to 243 ± 3 MPa, which is significantly higher than that of pure Cu (130 MPa). Orowan strengthening and grain refinement strengthening induced by dispersed nano-WC particles are the main strengthening mechanisms. Due to the load-transfer strengthening, the yield strength of the SPS composite is improved to 271 ± 2 MPa. After hot rolling, the yield strength is further increased to 315 ± 2 MPa, owing to the additional contribution of dislocation strengthening originating from the plastic deformation process. The proposed method in this study provides an advanced pathway for the preparation of ceramic nanoparticle dispersion-strengthened metals.