Impact Analysis of Microscopic Defect Types on the Macroscopic Crack Propagation in Sintered Silver Nanoparticles

Sintered silver nanoparticles (AgNPs) are widely used in high-power electronics due to their exceptional properties. However, the material reliability is significantly affected by various microscopic defects. In this work, the three primary micro-defect types at potential stress concentrations in sintered AgNPs are identified, categorized, and quantified. Molecular dynamics (MD) simulations are employed to observe the failure evolution of different microscopic defects. The dominant mechanisms responsible for this evolution are dislocation nucleation and dislocation motion. At the same time, this paper clarifies the quantitative relationship between the tensile strain amount and the failure mechanism transitions of the three defect types by defining key strain points. The impact of defect types on the failure process is also discussed. Furthermore, traction-separation curves extracted from microscopic defect evolutions serve as a bridge to connect the macro-scale model. The validity of the crack propagation model is confirmed through tensile tests. Finally, we thoroughly analyze how micro-defect types influence macro-crack propagation and attempt to find supporting evidence from the MD model. Our findings provide a multi-perspective reference for the reliability analysis of sintered AgNPs.