Impacts of Heat Treatment on Properties and Microstructure of Cu16at%Ag Conductors

CuAg in situ composite conductors are used as conductors for Florida Bitter magnets and potential candidates for pulsed magnets in the National High Magnetic Field Laboratory, and are likely exposed to temperatures higher than ambient during operations in magnets. The conductors are fabricated by cold rolling that introduces lattice distortions and high densities of interfaces in a unit volume. High temperature exposure by the conductors may affect the characteristics of the lattice distortions and the interfaces. The lattice distortion and density of the interface affects the mechanical properties of the conductors, such as the tensile and yield strength, as well as the electrical conductivity of the composites. Understanding the performance of the conductors after they are exposed to high temperature heat treatments helps one to make good use of them for magnets and to manufacture conductors to meet the requirements of the magnets, particularly when the magnetic stress reaches the limit of the mechanical strength of the conductors. The goal of this research is to understand the microstructure evolution of the Cu16at%Ag after the high temperature heat treatment and to relate such microstructural features to mechanical tensile strength and electrical conductivities.