Time dependent behavior of sintering mechanism and mechanical failure response of nano-silver under pressure-assisted bonding

Due to low density and difficult control of grain coarsening, pressure-less sintering technology is gradually becoming unsuitable in large-area sintering. Pressure-assisted sintering can significantly increase density and refine microstructure by applying pressure, while reducing sintering temperature and shortening process time. Previous studies on sintering mechanisms primarily focused on non-pressure sintering, and the conventional framework still employed the two-sphere approach, failing to precisely represent the nanoparticle sintering behavior. This study employed molecular dynamics (MD) simulations to investigate the sintering process and mechanical properties of silver (Ag) nanoparticles during pressure-aided sintering. The effects of sintering time on densification behavior and strength characteristics of nanostructured silver were analyzed. Atomic diffusion of nano-Ag was quantified by monitoring the mean square displacement (MSD) in real time. Common neighborhood analysis was employed to identify the evolution of crystal structure during sintering process. It is worth noting that we conducted secondary MD simulations on the structure after sintering to investigate the mechanical response characteristics of the sintered body. The fracture mechanism of nanostructured Ag was investigated through axial stretching computational modeling. In addition, we innovatively used fracture morphology to accurately analyze the fracture mode of the sintered body, which offers valuable theoretical support for utilizing nanostructured Ag in large-scale sintering applications.