Homogeneous Cu-Fe super saturated solid solutions prepared by severe plastic deformation

TL;DR

This study demonstrates that severe plastic deformation can produce a homogeneous Cu-Fe supersaturated solid solution by dissolving Fe filaments, with the process being influenced mainly by total strain rather than strain rate.

Contribution

It provides new insights into the formation of supersaturated Cu-Fe solutions through severe plastic deformation and characterizes the resulting nanostructures and composition gradients.

Findings

Alpha-Fe filaments dissolve during deformation forming a supersaturated solution.

Dissolution rate correlates with total plastic strain, not strain rate.

Asymmetric composition gradients indicate deformation-induced intermixing.

Abstract

A Cu-Fe nanocomposite containing 50 nm thick iron filaments dispersed in a copper matrix was processed by torsion under high pressure at various strain rates and temperatures. The resulting nanostructures were characterized by transmission electron microscopy, atom probe tomography and M\"ossbauer spectrometry. It is shown that alpha-Fe filaments are dissolved during severe plastic deformation leading to the formation of a homogeneous supersaturated solid solution of about 12 at.% Fe in fcc Cu. The dissolution rate is proportional to the total plastic strain but is not very sensitive to the strain rate. Similar results were found for samples processed at liquid nitrogen temperature. APT data revealed asymmetric composition gradients resulting from the deformation induced intermixing. On the basis of these experimental data, the formation of the supersaturated solid solutions is discussed