Multi-Material Processing By Lens

During the past few years, solid freeform fabrication has evolved into direct fabrication of metallic components using computer aided design (CAD) solid models. [1-4] Laser Engineered Net Shaping (LENS™) is one such technique [5-7] being developed at Sandia to fabricate high strength, near net shape metallic components. In the past two years a variety of components have been fabricated using LENS™ for applications ranging from prototype parts to injection mold tooling. [8] To advance direct fabrication capabilities, a process must be able to accommodate a wide range ofmaterials, including alloys and composites. This is important for tailoring certain physical properties critical to component performance. Examples include graded deposition for matching coefficient ofthermal expansion between dissimilar materials, layered fabrication for novel mechanical properties, and new alloy design where elemental constituents and/or alloys are blended to create new materials. In this paper, we will discuss the development ofprecise powder feeding capabilities for the LENSTM process to fabricate graded or layered material parts. We also present preliminary results from chemical and microstructural analysis.