| Abstract Scope |
Rapid advances in 3D printing of metals have enabled widespread used in industry. Key questions remain as to how to qualify printers and certify parts, especially in terms of defect structures. Under support from the NASA-ULI program, a multi-university team is determining process windows, characterizing microstructures and surface finish, and measuring fatigue resistance in 4-point bend fatigue. Preliminary results point to similar process windows for the same model at different locations when using a consistent source of Ti-6Al-4V powder. Microstructure and basic mechanical properties can be predicted from thermal history albeit heuristically. Transferring the methodology to an aluminum alloy in a different printer, however, required re-evaluation of melt pool sizes, which is basic to the proposed physics-based approach to qualification. Overall ICME needs include the need for computational tools that predict melt pool shape & size, melt pool stability, microstructure formation, including texture, diffusion, and solid state phase transformation. |