This study focuses on the mechanical alloying behaviour of equiatomic Cu-Nb powder mixtures subjected to ball milling at temperatures between 300 and 900 K. A homogeneous amorphous phase forms at room temperature. The increase of processing temperature promotes the formation of mixtures of amorphous and nanostructured Cu and Nb phases below 650 K, and of nanostructured Cu-Nb composites above 650 K. The grain size of Cu and Nb phases increases with temperature according to a power-law kinetics. (C) 2015 Elsevier B.V. All rights reserved.