Simulation of the sintering densification and shrinkage behavior of powder-injection-molded 17-4 PH stainless steel

This study simulates the sintering behavior of powder-injection-molded 17-4 PH stainless steel to predict the geometry of the sintered components. Sintering is considered as the viscous deformation process of a porous body under the influence of sintering stress. Consequently, modified constitutive equations applicable to linear viscous, compressible material, based on a continuum-mechanics approach, were utilized in simulating the sintering kinetics, with grain-boundary diffusion as the dominant densification mechanism. Quenching and other experiments were conducted to quantify the densification and grain-growth behavior of the powder-injection-molded 17-4 PH samples during sintering, to determine the material parameters required for the constitutive model. The predictive capability of the model was verified by comparing the theoretical calculations with the experimentally observed variation in sintering shrinkage of the samples determined by dilatometry. The predictions underestimate shrinkage above 700 degreesC, a factor related to the volume change from the phase transformations observed during the sintering.