Improving the Additive Manufacturing Processability of a γ/γ′ Cobalt-Based Superalloy Through Tailored Chemical Modifications Without Degrading Hot Mechanical Properties

This study aims to optimize the content of minor elementsMinor elements (C, B, Zr, Si, Hf) to enhance the manufacturability of γ/γ′ cobalt-based superalloysSuperalloys by additive manufacturingAdditive manufacturing without degrading hot mechanical propertiesMechanical properties or oxidationOxidation resistance. Results show that reducing the amount of minor elementsMinor elements improves resistance to liquid phase crackingCracking during additive manufacturingAdditive manufacturing. However, removing these elements leads to a degradation of grain boundaryGrain boundary strength or a reduction in the efficiency of the protective oxide layer at high temperaturesHigh temperature. To reconcile these different aspects, the contents of minor elementsMinor elements are adjusted in a γ/γ′ cobalt-based superalloySuperalloys following the study of its solidificationSolidification path. The chemical modifications enable the development of various crack-free microstructuresMicrostructure by directed energy deposition, which is unattainable before the chemical modifications. CreepCreep and cyclic oxidationCyclic oxidation testing show that these chemical modifications do not affect the initial properties of the superalloySuperalloys.