Influence of a high magnetic field on the microstructure and properties of a Cu-Fe-Ag in situ composite

The influence of a magnetic field during heat treatments was studied for a deformation-processed Cu−14Fe−0.1Ag in situ composite produced by thermo-mechanical processing. A high magnetic field during initial heat treatment promoted the spheroidization and refinement of Fe dendrites, and decreased the diffusion activation energy of Fe atoms in the Cu matrix, which promoted Fe atom precipitation. The resultant in situ composite had thinner Fe fibers, higher tensile strength and better conductivity. A high magnetic field during intermediate heat treatment increased the conductivity and tensile strength. The strength, conductivity and elongation to fracture of a Cu−14Fe−0.1Ag in situ composite could be improved simultaneously using a high magnetic field during the initial, intermediate and final heat treatment. The following combination of properties could be produced by the Cu−14Fe−0.1Ag in situ composite at η=7.8 after isochronic aging for 1 h using 10 T magnetic induction intensity: (i) 1149 MPa tensile strength, 60.3% IACS conductivity and 3.3% elongation; or (ii) 1093 MPa, 61.9% IACS and 3.5%; or (iii) 1006 MPa, 63.7% IACS and 3.7%.