Microstructure and properties of cold drawing Cu-2.5% Fe-0.2% Cr and Cu-6% Fe alloys

Abstract

High strength and high conductivity Cu-based materials are key requirements in high-speed railway and high-field magnet systems. Cu-Fe alloys represent one of the most promising candidates due to the cheapness of Fe compared to Cu-Ag and Cu-Nb alloys. The high strength of Cu-Fe alloys primarily relies on the high density of the Cu/Fe phase interface, which is controlled by the co-deformation of the Cu matrix and Fe phase. In this study, our main attention was focused on the deformation behavior of the Fe phase using different scales. Cu-2.5% Fe-0.2% Cr (in weight) and Cu-6% Fe alloys were cast, annealed, and cold drawn into wires to investigate their microstructure and properties evolution. Cu-6% Fe contains Cu matrix and Fe, which become the primary particles in the micrometer scale after solution treatment. Cu-2.5% Fe-0.2% Cr contains Cu matrix and Fe precipitate particles in a nanometer scale after solution and aging treatment. The Fe primary particles were elongated and evolved into ribbons in a nanometer scale while the Fe precipitate particles were hardly deformed even at a drawing strain of 6. The reason for the unchanging characteristics of Fe precipitate particles is due to the size effect and incoherent phase interface of Cu matrix and Fe precipitate particles. The strength of both Cu-6% Fe and Cu-2.5% Fe-0.2% Cr alloys increases with the increase in the drawing strain. The electrical resistivity of Cu-6% Fe gradually increases and that of Cu-2.5% Fe-0.2% Cr keeps almost constant with the increase in the drawing strain.

Influences of Alternating Magnetic Fieldson the Growth Behavior and Distribution of the Primary Fe Phasein Cu-14Fe Alloys during the Solidification Process

“…One of the key issues in the research of Cu-Fe composites is improvement of the morphology and distribution of the primary Fe phase. Several studies have reported a refined Fe grain size with the addition of micro-alloying elements such as Cr [16], Ni [17], Si [18], Co [19], and Ag [20]. This multi-alloying method can improve the strength of the composites.…”

Effects of an Alternating Magnetic Field/Ag Multi-Alloying Combined Solidification Process on Cu–14Fe Alloy

“…Researchers have introduced multi-alloying in Cu–Fe alloys to accelerate the precipitation of Fe during the solidification process by addition of micro-alloy elements, thus inhibiting the dissolution of Fe atoms in the Cu matrix. Ag has been widely studied as a third component to lower the solid solubility of Fe in Cu, and improve the strength of the material without markedly worsening the conductivity [2,5,6,7,8]. Meanwhile, because Fe atoms diffuse relatively slowly from a supersaturated Cu solid solution at room temperature, intermediate heat treatment and final aging treatment are often used to promote precipitation of Fe atoms [9,10,11].…”