Anisotropy of mechanical properties of DMD build Inconel 738

Anisotropy of stress-strain behavior, fracture toughness and fatigue crack growth rate was studied for Inconel 738 material build by the dynamic material deposition technique (DMD). The as-build material showed large-scale microstructure defined by linear molten pool tracks as well as linear arrangement of the precipitates in the solidification/build up directions. It appeared that the solidification direction defined the transverse anisotropy of the elastic modulus, whereas the rastering by build pool tracks gave rise to much complex anisotropy seen in fracture toughness. The fatigue crack growth rate was influenced by crack directional changes and crack branching but no clear relation to specimen orientation was observed. The obtained testing results, complemented with fractography and microstructural analysis broaden our insight on the formation of material properties by the DMD process.