Discrepancies in the Microstructures of Annealed Cu-Zr Bulk Alloy and Cu-Zr Alloy Films.

Copper-zirconium bulk alloy and Cu-Zr alloy films are prepared by vacuum smelting and magnetron sputtering, respectively, and subsequently annealing is conducted. Results show that Cu-Zr bulk alloy and alloy films exhibit significantly different microstructure evolution behaviors after annealing due to different microstructures and residual stress states. CuxZr alloy compounds disperse at the grain boundary of Cu grains in as-cast and annealed Cu-Zr bulk alloys. However, unlike bulk alloys, a large number of polyhedral Cu particles are formed on the Cu-Zr thin films' surface upon thermal annealing. Kinetically, the residual compressive stress in the Cu-Zr films promotes the formation of Cu particles. The influencing factors and the path for mass transport in the formation of the particles are discussed. The large-specific surface area particles/film composite structure has potential applications in Surface-Enhanced Raman Scattering, catalysis, and other fields.