Methods to rapidly optimize materials for Additive Manufacturing processes

ABSTRACT: Powder-bed based additive manufacturing (AM) technologies typically involve rapid solidification after a laser or electron beam melts a region of powder. These powders can have an associated cost as much as an order of magnitude greater than the bulk material. Although less costly powders exist, they have large size and shape distributions which leaves the final part with a less than optimal finish and microstructure. Input from powder angle of repose, Continuous Cooling Transformation (CCT) diagrams, thermo-mechanical boundary conditions, 3-Dimensional Finite Volume (3DFV) methodology, and part geometry in the form of an STL file, will be utilized in University of Louisville"s (U of L) Dislocation Density based Crystal Plasticity Finite Element Model (DDCP-FEM) to predict local and global strengths, grain morphologies, and other layer-by-layer interfacial characteristics. By employing a model guided Design of Experiment approach using Mound Laser & Photonics Center"s (MLPC) direct metal laser sintering (DMLS) development cell, the parameters given by the model can be experimentally tested, validated, and used for input for the iterative model. In addition, an Adaptive Metallic Powder Layering System will be developed to address the key issue of uniformly layering inexpensive powders in a method compatible with DMLS. BENEFIT: Due to the costs and the relatively small number of usable powder feedstock materials, the proposed work would not only provide savings in both cost and time for optimization and fabrication of components, but would allow for less traditional powder feedstock materials to be used. The cost of powder feedstock materials currently considered appropriate for DMLS can be as much as an order of magnitude greater than their bulk counterparts. The time savings for engineering development in the form of rapid prototyping of designs as well as complex geometries that do not lend themselves to conventional machining techniques would greatly benefit both commercial and military applications.