Consolidation of dispersion strengthened copper-niobium carbide composite prepared by in situ and ex situ methods

In this paper, Cu-20vol%NbC composite was prepared by in situ and ex situ processing methods. In in situ method, a mixture of Cu-Nb-C was mechanically alloyed in a high energy planetary mill while in ex situ method, a mixture of Cu-NbC powder was mixed in a low energy ball mill. Consolidation of the composite powder was systematically studied by pressing the powder at different compaction pressures, i.e. in the range of 350-650 MPa, followed with sintering at 900 °C for an hour. The presence of the NbC particle in copper matrix of the Cu-Nb-C sintered sample has been confirmed by X-ray diffraction and energy dispersive X-ray analysis. In situ composite has higher hardness and electrical conductivity than its counterpart due to a homogenous distribution of fine NbC particle and good NbC-Cu adhesion bonding. Higher compaction pressure has increased the hardness, electrical conductivity and density of the composites.