Directed light fabrication (DLF) is a rapid fabrication process that fuses gas delivered metal powders within a focal zone of a laser beam to produce fully dense, near-net shape, 3-dimensional metal components from a computer generated solidmodel. Computer controls dictate the metal deposition pathways, and no preforms or molds are required to generate complex sample geometries with accurate and precise tolerances. The DLF technique offers unique advantages over conventional thermomechanical processes or thermal spray processes in that many labor and equipment intensive steps can be avoided to produce components with fully dense microstructures. Moreover, owing to the flexibility in power distributions of lasers, a variety of materials havebeen processed, ranging from aluminum alloys to tungsten, and including intermetallics such as Mo{sub}5Si{sub}3. Since DLF processing offers unique capabilities and advantages for the rapid fabrication of complex metal components, an examination of themicrostructural development has been performed in order to define and optimize the processed materials. Solidification studies of DLF processing have demonstrated that a continuous liquid/solid interface is maintained while achieving high constant cooling rates that can be varied between 10 to 10{sup}5 K s{sup}(-1) and solidification growth rates ranging up to 10{sup}(-2) m s{sup}(-1).
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