Abstract:With the ongoing advancement of electronic components towards higher power, miniaturization, and enhanced reliability, the performance requirements for copper strips used in these components are also becoming increasingly stringent. Copper strips must not only maintain high electrical and thermal conductivity but also exhibit superior strength and resistance to softening. In this paper, characterization methods such as EBSD and TEM were employed to systematically investigate the influence of trace Ag (0.0013%~0.0208%) on the microstructure and anti-softening performance of Cu-Ag alloys. The research findings indicated that trace Ag can refine the microstructure of Cu-Ag alloys, significantly enhancing their mechanical properties at high temperatures and increasing softening temperature. Specifically, the softening temperature of alloy with 0.0208% Ag (S4) reached 408 ℃, which was 80 ℃ higher than that of alloy with lower Ag content (S1, 0.0013%), and the hardness increased by approximately 26%. Trace Ag was solid-solved in the matrix, causing lattice distortion and significantly impeding the slip movement of dislocations, thereby effectively retarding the recrystallization process of the alloy. Additionally, the addition of trace Ag also exerted a pinning effect on the grain boundaries, significantly inhibiting grain growth and delaying the occurrence of recrystallization. The analysis revealed that recrystallization was the primary cause of the high-temperature softening phenomenon of the alloy.