Modelling the influence of process parameters on precipitate formation in powder-bed fusion additive manufacturing of IN718

Abstract

In this work, we have developed a two-scale (finite element + phase field) model for simulating the precipitate evolution in IN718 in powder-bed fusion additive manufacturing. The thermal simulations at the scale of the component are resolved at the level of a single stripe of the scan path. This resolution allows to model various process parameters (or scan strategies) in complex geometry domains, here demonstrated by an impeller, and predicts the complete thermal history within each finite element layer. The predicted thermal history is in-full passed to multiple phase-field simulation representative volume elements (RVEs) that explicitly model the evolution of the γ′ and γ″ precipitates in various locations of the impeller. We simulate the precipitate microstructures in different regions of the impeller and demonstrate the influence of process parameters on the volume fraction, size, and shape of the precipitates. Although no precipitates are found to form during the standard printing conditions (for instance EOS M290), we show that changing the process parameters such as stripe width or chamber temperature may induce significant precipitation in the as-built component.