| Powders of copper-based nanocomposites with nominal composition of 10 and 20 vol.% of NbC were prepared in situ from elemental powders with mechanical alloying in a planetary mill. Powder batches milled for 28.8 ks were vacuum encapsulated in copper cans and consolidated via hot extrusion at 873K. Microstructural characterization in both the as-milled powders and the extruded materials were performed using X-ray diffraction (XRD), scanning and transmission electron microscopy (SEM and TEM). Mechanical properties were assessed with microhardness measurements. SEM observations of extruded Cu powders with 20 vol.% of NbC revealed prior particle boundaries and also Cu rich regions. Both extruded nanocomposites present a good densification without appreciable porosity. Microhardness values obtained for extruded Cu-10 vol.% of NbC powder are similar to those obtained in the as-milled condition. For Cu-20 vol.% of NbC a slight decrease in microhardness is observed after consolidation. |
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