Effect of Ti additions on microstructure and mechanical properties of Cu–Cr–Zr alloy

Abstract

Ti additions in Cu–Cr–Zr alloys are useful for achieving high mechanical properties. In this work, the influence of Ti contents (0.25 wt%, 0.6 wt%, and 1.02 wt%) on the microstructure, mechanical, and electrical properties of Cu–Cr–Zr alloys has been investigated experimentally, along with thermodynamic and kinetic calculations. The electrical conductivity decreased but the hardness/strength increased with increasing Ti content. The lower electrical conductivity is due to increased electron scattering through the solution of more Ti atoms in the Cu matrix. As for the higher hardness/strength, it is mainly owing to higher dislocation density and finer FCC-Cr precipitates. Furthermore, a model considering the size distributions of precipitates is adopted to calculate precipitation strengthening quantitatively. The calculated yield strengths are consistent with the experimental ones for the alloys. The thermodynamic and kinetic calculations reveal that increasing Ti content can facilitate the nucleation of FCC-Cr but enhance its activation energy, hence hindering the growth process. The present work study can provide an effective strategy for producing copper alloys with expected performance.