Microstructure Characterization and Thermal Stability of Nanocrystalline Cu Powders Processed via Cryomilling

Abstract

Nanocrystalline Cu powders with a grain size of about 32 nm have been successfully synthesized using cryomilling technique. The effect of cryomilling time on the particle size, grain size, and structure of cryomilled Cu powders were investigated. The thermal stability of cryomilled Cu powders was studied and the study described the enthalpy change due to grain growth and stress relaxation of cryomilled Cu particles by annealing. The stress relaxation process associated with reordering of the grain boundaries was found to occur at 280°C. The grain growth process was found at 330°C and the thermal release of the grain growth was detected by differential scanning calorimetry analysis.