Viscous sintering modeling of dissimilar sintering trajectories: A study on paste-based additive manufactured 17-4 PH stainless steel

Dissimilar sintering trajectories describe temperature- and kinetics-dependent variations in densification behaviors, driven by changes in diffusion mechanisms, phase transformations, and heating rate. Modeling such trajectories is critical for predicting densification and deformation in sinter-based additive manufacturing (AM). This study presents the first investigation of the sintering behavior of 17-4 PH stainless steel produced by paste-based AM process. A modeling workflow based on the continuum theory of sintering is developed, integrating activation energies from mechanistic analysis and accounting for bulk modulus evolution induced by phase transformations. Despite significant variations in sintering trajectory caused by heating rate and decarburization, the model successfully simulates densification during the heating stage, reaching up to 99% density with a root mean square error (RMSE) less than 1.1%. The results provide new insights into the sintering response of paste-based additive manufactured steel and demonstrate the capability of such physics-informed model to capture complex sintering kinetics. The proposed modeling workflow could be generalizable to a wider range of materials exhibiting dissimilar sintering behaviour as well as other sinter-based AM processes.