Microstructural refinement and performance improvement of Cu–36 wt% Zn alloy by Al₂O₃ nanoparticles coupling electromagnetic stirring

Cu–36 wt% Zn alloy is widely used in valves of water and heating and auto parts, etc. Nevertheless, the structure is still coarse, and performances are much poor. The structure and performances of Cu–36 wt% Zn alloy were investigated by adding Al₂O₃ nanoparticles and stirring. Results indicate that by Al₂O₃ nanoparticles coupling electromagnetic stirring, the Cu–36 wt% Zn alloy with refined microstructure was successfully prepared. The average grain size is refined by 99 % compared with that without nanoparticles and stirring. The tensile strength (R_m) and percentage elongation after fracture (A_11.3) increase by 20.58 % and 19.40 %, respectively, compared with that without nanoparticles and stirring. Nanoparticles increase heterogeneous nucleation rate by 50 % compared with that without nanoparticles. The depth of dezincification layer decreases by 78.71 % compared with that without nanoparticles and stirring, as protective layer (Cu–Al₂O₃–Zn) is completely formed around the grain boundaries.