Direct Digital Manufacturing (DDM) of Metallic Components: Controlled Thermal Processing

The first objective of this Phase II is to develop and demonstrate thermally controlled direct digital manufacturing (DDM) of Ti-6Al-4V that will have the ability to produce uniform/desired microstructure in a repeatable manner. The proposed method will be designed to provide a quasi steady and uniform state of thermal transport in the build and substrate material for the duration of deposition and subsequent cooling. The thermal control will be developed based on considerations such as the elimination of layered microstructure, minimization of beta grain size, transition from columnar to equiaxed microstructure, and to obtain morphology of microstructure that produces higher fatigue properties. The as-deposited material is anticipated to exhibit isotropic properties, with its fatigue properties in the upper bins of the Cast+HIP Ti-6Al-4V. An additional objective of this Phase II is to explore a method to induce vibration in the melt pool in order to further refine the prior-beta grains and to enhance the fatigue properties. The technology transition effort in Phase II Option will demonstrate the thermally controlled DDM to produce a representative complex geometry of interest to a jet engine OEM.