Abstract
The precipitation of nano-sized Cr clusters was investigated in a commercial Cu-1Cr-0.1Zr (wt.%) alloy processed by equal-channel angular pressing and subsequent aging at 550 °C for 4 h using Small-Angle Neutron Scattering (SANS) measurements and High-Angle Annular Dark-Field-Scanning Transmission Electron Microscopy (HAADF-STEM). The size and volume fraction of the nano-sized Cr clusters were estimated using both techniques. The parameter values assessed by SANS (d ∼ 3.2 nm, F_v ~ 1.1 %) agreed reasonably with those by HAADF-STEM (d ∼ 2.5 nm, F_v ∼ 2.3 %). In addition to the nano-sized Cr clusters, HAADF-STEM indicated the presence of rare cuboid and spheroid sub-micronic Cr particles measuring approximately 380–620 nm in mean size. Both techniques did not evidence the presence of intermetallic Cu_xZr_z phases within the aging conditions.

Key words
Cr-cluster, precipitation, ECAP, Cu-Cr-Zr alloy, SANS, HAADF-STEM

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