An iterative approach of hot isostatic pressing tooling design for net-shape IN718 superalloy parts

Abstract

Powder hot isostatic pressing is a resource-efficient approach for net-shape manufacture of high-value nickel-based superalloy structures. One of the key challenges to its application is the availability of modelling tools that can predict the geometrical changes that occur during the consolidation process in order to design the tooling required. In this work, the utility of a finite element code, based on the plastic collapse model, was assessed. The finite element model was then combined with an optimisation toolbox to design (in an iterative process) the tooling required to accommodate the powder consolidation process. The model was validated for IN718 superalloy using a demonstrator with complex features. Microstructural characterisation was also performed to assess the degree of densification. Although the finite element model did not account for creep deformation, good predictions were obtained. Nevertheless, predictions of the dimensions of consolidated samples were obtained, which were typically within 1 % of the observations, suggesting that plastic collapse accounts for 99 % of the geometrical changes due to the densification process for the range of hot isostatic pressing parameters investigated.