The Laser-Engineered-Net-Shaping (LENSTM) process uses a laser to create a molten pool on the surface of a substrate in which metal powder is then injected to increase the volume of the pool. The laser spot is selectively scanned to additively build up the required material in the desired shape. In a sequential fashion, each cross-sectional layer of the object is taken from a 3-D CAD file and deposited until an entire object is created. Many materials have been deposited using this technique, including steels and titanium alloys. Metal-matrix composites (MMCs) have been produced by the simple method of using coated particulate composite particles. The deposition of aluminum and its alloys is challenging because aluminum absorbs little incident laser energy. The ability to produce these materials may significantly impact NASA's ability to fabricate or repair various components for advanced rocket engines. This proposal aims to develop the methodology to deposit high aluminum alloys during Phase I, and also show the feasibility of producing aluminum MMCs. Phase 2 will further optimize the aluminum alloy deposition and develop the process for aluminum MMC deposition, and demonstrate component manufacture with suitable testing. POTENTIAL COMMERCIAL APPLICATIONS The Laser-Engineered-Net-Shaping (LENSTM) process was first commercialized in 1997, and since then systems have been sold to various government, university and industrial organizations, including NASA MSFC. The process conditions to deposit a wide variety of materials have been developed. The deposition of aluminum and its alloys is challenging due to the fact that aluminum absorbs little incident laser energy. The ability to deposit near-net-shape aluminum components will enable the manufacture or repair a wide variety of components. Al-MMCs are finding many applications in rocket engines, including thrust-chamber jackets, support structures, and cryogenic pump components. The ability to repair Al-MMCs may be an enabling technology to reduce the life-cycle cost of these materials by allowing repairs to be made.
