Microstructure and properties of a novel Cu-Cr-Yb alloy with high strength, high electrical conductivity and good softening resistance

Abstract

A novel Cu-Cr-Yb alloy was designed and processed by thermo-mechanical treatment. The microstructure, mechanical and electrical properties were investigated in detail. The results showed that the Cu-Cr-Yb alloy had a higher strength, a better softening resistance and a considerably high electrical conductivity than the Cu-Cr alloy. After 80% cold rolling followed by aging at 500 °C, the peak-aged Cu-Cr-Yb alloy had a Vickers hardness of 160 ± 1 HV, a tensile strength of 465 MPa, an elongation of 21.1% and an electrical conductivity of 89.5 %IACS, respectively. After a long-time aging at 500 °C, the nano-scale Cr-rich precipitates with FCC structure in the Cu-Cr-Yb alloy hardly coarsened. Thermodynamics analysis showed that the Cr-rich precipitates were inclined to nucleate with FCC structure, and the addition of Yb hindered the nucleation of the Cr-rich precipitates.