Effect of Ag on Properties, Microstructure, and Thermostability of Cu–Cr Alloy

Abstract

Cu–Cr-based alloys exhibit excellent electrical conductivity and strength, but their poor thermal stability limits their application in industry. In this paper, Cu–0.2Cr (at. %) and Cu–0.2Cr–0.12Ag (at. %) alloys were prepared to study the effect of Ag on the properties, microstructure, and thermal stability of the Cu–Cr alloy. Microstructure and precipitation were observed by an optical microscope (OM) and a transmission–electron microscope (TEM). After cold-drawing by 99.9% and aging at 450 °C for 2 h, the peak hardness and electric conductivity of the Cu–Cr alloy were 120.3 HV and 99.5% IACS, respectively, and those of the Cu–Cr–Ag alloy were 135.8 HV and 98.3% IACS, respectively. The softening temperature of the Cu–Cr alloy was 500~525 °C, and that of the Cu–Cr–Ag alloy was about 550 °C. The creep strains of the Cu–Cr and Cu–Cr–Ag alloys at 40 MPa and 400 ℃ for 50 h were 0.18% and 0.05%, respectively. Ag elements improved the thermal stability of the Cu–Cr alloy. Recovery and recrystallization occurred before the coarsening of precipitates during the softening process. Ag atoms mainly improved the softening resistance of the alloy by delaying recrystallization, and mainly increased creep resistance by preventing the increase in mobile-dislocation density.

Effect of Sn Addition on Microstructure, Aging Properties and Softening Resistance of Cu-Cr Alloy

“…The softening temperature of the 90% cold-rolled Cu-Cr-Y alloy is about 550 °C and higher than the Cu-Cr alloy [ 14 ]. Additionally, the softening temperature of the 99% cold-drawn Cu-Cr-Ag alloy also increased from 515 °C to 550 °C by Ag addition [ 31 ].…”

Effects of La Addition on Microstructure Evolution and Thermal Stability of Cu-2.35Ni-0.59Si Sheet

“…The electrical conductivity was obtained by measuring its resistivity (LSR Seebeck, Linseis, Zehlb, Bavaria, Germany) and utilizing the conversion relationship between resistivity and conductivity. Due to the need for alloys to serve at high temperatures, it is crucial to evaluate the thermal stability of materials [30]. The high-temperature stability comparison experiment involves selecting an alloy sheet after cold rolling, and conducting a heat treatment at 850 • C for 3 h, followed by observing the microstructure at room temperature.…”

Study on the Microstructure and Properties based on Composition Regulation of Cu-Fe-Mg-Ti Alloy

“…In order to meet the requirements of high-density assembly of integrated circuit products, integrated circuit leadframe materials are developing in the direction of high density with high performance, high integration, multi-lead and narrow pitch [4][5][6][7] . Leadframe materials currently available on the market include Cu-Fe-P alloys [8][9][10], Cu-Cr-Zr alloys [11][12][13] , Cu-Ni-Si alloys [14][15][16] and other series of alloys [17][18][19] .…”