Precipitation and strengthening mechanisms in Cu-0.27wt.% Sc alloy: Linking thermomechanical treatment, microstructure and properties

Kurzfassung

Enhanced mechanical and electrical conductivity of low alloyed Cu-Sc alloys were systematically investigated with a focus on precipitation, solid solution, and dislocation strengthening. A Cu-0.27 wt% Sc alloy subjected to 50 % cold rolling and peak aged for 0.5 h at 450 °C achieved a high yield strength of 434 MPa and a conductivity of 42.5 MS/m (73.3 % IACS). The microstructural evolution during aging was characterized by SEM, TEM, and APT, revealing the rapid formation of nanoscale, plate-like Cu4Sc precipitates growing with increasing aging time. The enhanced precipitation response in cold-worked conditions was attributed to dislocation-assisted nucleation and solute flux driven by strain fields. A mechanistic strengthening model incorporating work, solid solution, and particle hardening accurately predicts the time-dependent mechanical response. The results underline the capability of Sc as an effective alloying element for high-strength, high-conductivity copper alloys. Based on the observed kinetics and mechanisms, a multi-stage thermomechanical treatment involving intermediate deformation steps is proposed to further exploit this strengthening potential.