Study On Microstructure And Properties Of Deformation Processed Cu-Fe In Situ Composites

With the development of high speed electrified railway, there is a higher need to the properties of conductivity materials, which need better combination of high strength, high electrical conductivity, and high thermal stability. At the same time,the materials should be economical in order to be widely used. The deformation processed Cu-Fe in-situ composites materials were developed with new demands.Deformation processed Cu-10Fe-1.5Ag, Cu-10Fe-1.5Ag-0.1Zr and Cu-10Fe-1Ag in situ composites were prepared by drawing and intermediate annealing. The microstructure, tensile strength, electrical conductivity and thermal stability were investigated. The main conclusions are as follows.The microstructure of the casting-state in cast structure and the deformation structure of Cu-10Fe-1.5Ag and Cu-10Fe-1.5Ag-0.1Zr were observed by SEM. The result indicates that the Fe dendrites were drawn into fibers with the expanding of compressive strain, and cross-section present vermicular structure.The tensile strength and electrical conductivity of deformation processed Cu-10Fe-1.5Ag and Cu-10Fe-1.5Ag-0.1Zr in situ composites were investigated. The result indicated that both the tensile strength and electrical conductivity went up with the increase of strain. The tensile strength heavily decreased with intermediate annealing, but the electrical conductivity was made better with the precipitation of Fe and Ag particle from the copper matrix.The effect of Ag on the electrical conductivity of deformation processed of Cu-Fe in situ composites was investigated. The result showed that the electrical conductivity was improved with Ag addition. The electrical conductivity of Cu-10Fe-1Ag alloys reached 57.9%IACS; and the electrical conductivity of Cu-10Fe-1.5Ag alloys was 52.2%IACS, with the strain 6.70.The effect of Zr in the thermal stability on the deformation processed of Cu-Fe in situ composites was investigated. The result showed that the softening temperature was improved with Zr addition. The softening temperature of Cu-10Fe-1.5Ag and Cu-10Fe-1.5Ag-0.1Zr alloys reached 450°C and 500°C at the strain of 6.70. The softening temperature increase 50°C with Zr element addition.The optimum combination property of Cu-10Fe-1.5Ag and Cu-10Fe-1.5Ag-0.1Zr alloys could be obtained, which were prepared by process AПand process BП, with the annealing temperature was 400°C as the strain was 6.70. The tensile strength and electrical conductivity of Cu-10Fe-1.5Ag reached 841MPa/58.6%IACS and 811MPa/60.9%IACS; the tensile strength and electrical conductivity of Cu-10Fe-1.5Ag-0.1Zr reached 959MPa/55.6%IACS and 854MPa /59.0%IACS.