Simultaneous increases of tensile strength and electrical conductivity by deep cryogenic treating in Cu-Fe and Cu-Cr in-situ composites

Deep cryogenic treating (DCT) was applied on Cu-14Fe and Cu-8Cr in-situ composites and its effects on mechanical property and electrical conductivity of the composites were investigated. For comparison, the effects of DCT on properties of the corresponding composites with 0.1%Ag alloying (i.e. Cu-14Fe-0.1Ag and Cu-8Cr-0.1Ag) were also investigated. The results showed that the ultimate tensile strengths of Cu-14Fe and Cu-8Cr were greatly raised by 106MPa and 56MPa after DCT, respectively, whereas those of the Cu-14Fe-0.1Ag and Cu-8Cr-0.1Ag remained unchanged. The increments of electrical conductivity in Cu-14Fe and Cu-8Cr were much higher than those in corresponding Cu-14Fe-0.1Ag and Cu-8Cr-0.1Ag. Before DCT, the electrical conductivities of Cu-14Fe and Cu-8Cr were lower than those of the Cu-14Fe-0.1Ag and Cu-8Cr-0.1Ag, respectively; whereas after DCT, the electrical conductivities of Cu-14Fe and Cu-8Cr were higher than those of the corresponding composites with 0.1%Ag micro-alloying. The possible mechanisms involved in the effects of DCT on the properties of composites were discussed in this paper.