Effect of Porosity on the Indentation Response of Polycrystalline Porous Sintered Silver

Sintered silver is widely used in power electronics packaging due to its excellent thermal and electrical properties, yet its inherent porosity significantly influences mechanical performance, particularly in terms of strength, deformation, and damage evolution. To systematically analyze these effects, numerical models with different porosities (10%, 20%, and 30%) are developed using a crystal plasticity finite element method (CPFEM). Pores are randomly distributed based on a Gaussian distribution to ensure a realistic spatial arrangement. The indentation response is evaluated by analyzing the load–displacement (P–h) curves, revealing that increasing porosity leads to a significant reduction in load-bearing capacity. Furthermore, the impact of pore distribution is examined by constructing models with different random pore configurations at a fixed porosity of 10%. The results indicate that variations in pore distribution have negligible influence on the macroscopic indentation response. Additionally, the orientation distribution function (ODF) analysis is conducted to assess grain orientation evolution during indentation, highlighting the pronounced influence of plastic deformation on crystallographic texture. The evolution of critical resolved shear stress (CRSS) and shear stress distribution further confirms the activation of slip systems during loading and the dominance of elastic recovery during unloading. Moreover, the contours of accumulated shear strain reveal strong strain localization around certain pores, indicating potential sites for crack initiation and subsequent propagation. The results of this study provide mechanistic insight into the deformation and damage behavior of porous polycrystalline metals and offer theoretical guidance for the microstructural optimization of sintered silver in high-reliability applications.