Optimizing strength and electrical conductivity of Cu–Fe–Ti alloy by pre-aging treatment

Abstract

Pre-aging treatment before cold rolling and final aging was introduced to optimize the mechanical properties and electrical conductivity properties of Cu-0.75Fe-0.35Ti alloy. The alloy was pre-aged at 540 °C for 6 h, then cold rolled with thickness reduction of 80%, followed by aging at 460 °C for 2 h (SARA). Vickers hardness, electronic conductivity and uniaxial tensile tests were conducted to measure the mechanical and electrical conductivity properties. Electron backscatter diffraction and transmission electron microscope were used to characterize the microstructural evolution. The results showed that the hardness, tensile strength and electrical conductivity of SARA were up to 198.2 ± 4.8 HV, 622.6 ± 6.3 MPa and 63.8% IACS, respectively, which were superior to those achieved without pre-aging. The enhanced mechanical properties of SARA were attributed to an increase in low angle boundaries (LABs), geometrically necessary dislocation (GND) density and volume fraction of precipitates, while the favorable electrical conductivity was ascribed to the enhancement of precipitation and resultant matrix purification.