Bulk Cu-Cr nanocomposites by high-energy ball milling and spark plasma sintering

A set of nanocomposite Cu-Cr powders with the grain size of these immiscible metals below 5 nm were prepared by high-energy ball milling. The powders were then consolidated by short-term (5 min) spark plasma sintering at 700-900 °C under pressure (50 MPa) to obtain essentially pore-free pseudo-alloys. The grain sizes in the produced bulk materials remained within the ranges 5-60 nm for Cr-based phase and 200-300 nm for Cu-based matrix. These nanocomposites have a Vickers microhardness up to 3.9 GPa and a specific electrical resistivity in the range 6-9.6 μΩ cm, which make them promising candidates for the application in high-voltage circuit breakers.