Deformation-Processed Cu-Fe In Situ Composite

The effect of solution and aging treatment on the structure and properties of Cu-Fe alloys and the effect of deformation, intermediate heat treatment, annealing treatment and doping with a little of Zr or Mg on the structure and properties of deformation-processed Cu-Fe in situ composite were investigated. The strength of materials was measured by MTS. The electrical resistivity of the composite wires was investigated by four-point measure. Microstructure observations were carried out by optical microscope SEM, TEM and XRD.The results showed that after 550 ℃ × 2 h aging treatment the Cu-Fe alloy presented favorite conductivity and strength. In deformation process the deformation began at a end of Fe dendrites, at last the Fe dendrites were drawn into fine ribbons with curl and fold form in cross-section. At the same time, the density dislocation and area of boundaries increased, which increased the strength and the resistivity of alloys. The strength increased with increasing of Fe content in alloy and deformation strain. Doping with Zr can increase the ultimate tensile strength of the Cu-Fe alloys by 10% and improve the themal stability of Cu-Fe composites, but the resistivity of materials increased a little. Doping with Mg resulted in embrittlement of Cu-Fe composites. Intermediate heat treatment can promote the precipitation of Fe from Cu matrix and decrease the density of defection, which obviously decreased the resisitivity of Cu-Fe composites. At the same time, it made Fe phase soft and accelerated the formation of Fe ribbons. But the intermediate heat treatment had no effect on change tendency of strength. After annealing at lower temperature the favorite properties of composite wires were obtained.The good combinations of the electrical conductivity and the ultimate tensile strength of Cu-Fe in situ composites are following. Cu-11.5%Fe: 70.6% IACS / 659 MPa (η = 6.63), 64.6% IACS / 752 MPa (η = 7.57) and 51.9% IACS/ 880 MPa (rj = 9.4). Cu-17.5%Fe: 58.6 % IACS / 936 MPa (tj = 6.63) and 53.7 % IACS / 1110 MPa (}] = 7.57). Cu-11.5%Fe-Zr: 61.4% IACS / 824 MPa (tj = 7.57).