Purpose This study aims to investigate the effect of particle size on the microstructure and mechanical behavior of sintered Cu, focusing on the differences in mechanical properties between sintered submicron Cu and sintered micron Cu for potential applications. Design/methodology/approach Crystallographic analysis was performed to assess the recrystallization degree and grain boundary characteristics. Nanoindentation testing was conducted to measure the Young’s modulus, work done and contact stiffness of sintered submicron Cu, sintered micron Cu and bulk Cu. Stress–strain constitutive equations for the three samples were derived from dimensionless equations, and the fracture toughness of two types of sintered Cu was evaluated based on the energy analysis method. Findings Sintered submicron Cu exhibits a higher degree of recrystallization and greater dislocation annihilation compared to sintered micron Cu, resulting in a higher proportion of high-angle grain boundaries and a lower dislocation density. The Young’s modulus of sintered submicron Cu is higher than that of sintered micron Cu, and bulk Cu exhibits the highest modulus, thus reflecting the negative relationship between porosity and Young’s modulus. The fracture toughness of sintered submicron Cu is greater than that of sintered micron Cu, which is attributed to its smaller grain size and porosity, as well as its higher Young’s modulus and degree of recrystallization. Originality/value This study provides theoretical foundations and mechanical performance data to support the design of high-reliability sintered Cu joints.
Huang et al. (Mon,) studied this question.