Enhanced Microstructural and Performance Characteristics of Cu–18 Pct Ag Composites Through Elemental Additions

Cu–Ag in-situ composites, renowned for their amalgamation of high strength and superior electrical conductivity, find extensive applications as conductors in high field magnets. This investigation delves into the microstructural intricacies and mechanical characteristics of Cu–18 pct Ag (wt pct) in-situ composites following the incorporation of alloying elements (Nb, Cr, and Zr) via a comprehensive process involving casting, heat treatment, and cold deformation. The outcomes reveal that the introduction of Nb or Cr elements intricately refines the Cu dendrites and eutectic phase. Simultaneously, the Cu matrix experiences fortification through the inclusion of Nb or Cr particles, imparting notable improvements in mechanical properties. Remarkably, Cr addition exhibits the most pronounced impact on elevating both ultimate tensile strength and hardness. Under a deformation rate (η) of 5.28, the ultimate tensile strength surges by 21.00 pct compared to that of the Cu–18 pct Ag alloy, albeit with a marginal 7.36 pct decrease in conductivity for the Cu–18 pct Ag–1 pct Cr alloy. The introduction of Nb augments ultimate tensile strength by 12.23 pct, with no apparent impact on conductivity under identical deformation conditions. In contrast, Zr addition significantly disrupts the precipitation of the Ag phase, fostering the formation of the intermetallic compound Cu4AgZr. This disruption induces a reduction in both mechanical properties and conductivity, leading to embrittlement at high drawing strains.