The role of particle size distributions on the macroscopic properties of sintering bodies

Computational approaches based on the viscous theory of sintering can be used to optimise the densification of ceramic components with complex architectures. Their application, however, is limited by the lack of reliable models for macroscopic properties that account for the evolving microstructure, particularly changes in particle size distributions (PSDs). This study analyses samples with distinct PSDs to quantify their influence on macroscopic properties, including the effective sintering stress and viscosities. Underlying microstructural mechanisms are captured using a coupled solid-state sintering and grain growth model within the Discrete Element Method. Model predictions show good agreement with experimental data. The results reveal limitations in existing phenomenological models, especially for systems with specialised PSDs, showing discrepancies up to 100%. Furthermore, the findings demonstrate that tailoring PSDs, for example, using bi-modal systems, can reduce sintering time by 50%. The study establishes a foundation for predictive modelling of ceramic sintering, enabling efficient process optimisation.