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.