Microstructural stability of nanostructured Cu alloys during high-temperature irradiation

The stability of model nanostructured Cu90Mo10 and Cu90W10 alloys during irradiation with 1.8 MeV Kr+ at very high temperatures was investigated. Significant coarsening occurs only above ∼0.6Tm in Cu90Mo10 and ∼0.8Tm in Cu90W10 (Tm is the melting point of Cu). Below these temperatures, nanoprecipitates nucleate and grow to a saturation diameter of ∼4 nm. These very small nanoprecipitates confer remarkable microstructural stability, with the Cu grain size remaining below 40 nm. Computer simulations help to explain why these nanostructures are so stable.