EFFECT OF HEAVILY DRAWING ON THE MICROSTRUCTURE AND PROPERTIES OF Cu-Cr ALLOYS

Abstract

Cu-Cr alloy is a kind of promising materials used as conductor due to its good strength and high conductivity. Heavy cold deformation could increase the strength effectively. Most of Cu and Cr phase are elongated into filaments during cold drawing. There exits plenty of Cu/Cr interface and the structure of Cu/Cr interface is thought to play an essential role in the properties of the Cu-Cr alloy. In this work, Cu-Cr wires were prepared by cold drawing method. The evolution of the microstructure and the structural change of phase interface during cold drawing have been investigated and the relationship between properties and microstructure also established. The microstructure consists of Cu matrix and Cr particles before cold drawing. As the drawing strain increases, both of Cu and Cr phases evolve into filamentary structure. Some residual Cr particles are still found in the alloy even at high drawing ratio. There is a relationship of (111) Cu / /(110) Cr between Cu fibers and Cr fibers at high strain levels. The Cu/Cr interface is non-coherent before cold drawing and gradually evolves into the coherent interface at high drawing strains. The inter-solution ability of Cu and Cr elements across the Cu/Cr interface is enhanced with the increase in the drawing strain. The coherent Cu/Cr interface and the increasing of interface density should be responsible for the

Fabricate of High-Strength and High-Conductivity Cu–Cr–Si Alloys through ECAP-Bc and Aging Heat Treatment

“…Cu-Cr alloys are widely used in integrated circuit lead frames, electric locomotive contact lines, and other fields due to its excellent electrical, thermal conductivity, and high strength [1][2][3]. The mechanical properties of the alloy can be improved by precipitation strengthening, however, the Cr element has a low solid solubility in Cu, especially at room temperature or lower Cr alloys [4], which makes it difficult to increase the strength of the as-cast Cu-Cr alloys.…”

Effect of Alloying Elements on the Microstructure and Performance of Cu-6 pctAg In-Situ Composites

“…[32] For example, at similar drawing strains, the Nb-rich phase is quite ductile, and can easily be deformed into fibers during drawing, [33] while the Cr-rich phase is less ductile and difficult to deform into filaments. [34] The addition of 0.2 pctZr to Cu-Ag alloys have been reported to suppress Ag precipitation in Cu-Ag alloys, thus, increasing the strength of the alloy while decreasing the conductivity. [35] In addition, the addition of Zr to Cu-Ag alloys leads to the formation of Cu 4 AgZr particles, which improves the mechanical properties of the alloy after annealing at high temperatures.…”