Effects of aging process on properties and precipitation kinetics of Cu–Cr–Zr alloy strips

Abstract

Cu–1.0Cr–0.1Zr alloy strips were prepared by solution, cold rolling and aging processes. The effects of aging process on the conductivity, mechanical properties and microstructure of the alloy were studied, and the precipitation kinetics was analyzed. The results showed that the Cu–1.0Cr–0.1Zr alloy exhibited the best comprehensive properties after aging at 430 °C for 180 min, with an electrical conductivity of 85.86% IACS, a hardness of HV 176.54, and a tensile strength of 552 MPa. For the samples aged at 430 °C from 30 to 180 min, the fcc-Cr and Cu8Zr3 phases grew from ~5 to ~8 nm, and the relationship between the precipitates and matrix changed from coherent to semi-coherent. In addition, the rod-like and spherical coarse particles (≥300 nm) of bcc-Cr phase were observed. The precipitation kinetics equations at different aging temperatures were established, the time–temperature–transformation (TTT) curve was plotted, and the precipitation activation energy was obtained as 65 kJ/mol.