Modeling of effects of vibration parameters on location-dependent initial relative density in powder metallurgy capsule filling

Power metallurgy hot isostatic pressing (PM-HIP), as a versatile manufacturing process, can produce net-shape or near-net-shape components with complicated geometries from materials that are not easily cast, deformed, or welded. In PM-HIP, capsule (or die) filling is a critical step to get dimensionally and microstructurally sound outputs. Particularly, capsule filling controls the initial relative density (homogeneity) of the PM-HIP compact. In this study, the pre-consolidation capsule filling process is simulated by the discrete element method (DEM), to capture the impact of vibration parameters, including the vibration frequency, amplitude, duration, and direction, on the initial relative density (RD). The output of the DEM model was imported into a user subroutine-based finite element of PM-HIP containing a combined constitutive model of compressive and consolidative mechanical behavior of powder. The simulation model was used to quantitatively study the relationships between the vibration parameters and the initial RD of the product. The ultimate results of this work have shown an optimal vibration frequency for maximizing the initial density. The study also quantitatively tested the relationship between the other vibration parameters and the initial relative density and provided the analysis.