R. Gansert, AMTS Incorporated, Simi Valley, CA; D. Grant, C. Melnyk, S. Schroeder, California Nanotechnologies, Inc., Cerritos, CA
Near-nano and nano-grained materials show great potential for applications in the aerospace industry. The Hall-Petch relationship cites the strengthening of materials by reducing the average crystallite (grain) size. A study is proposed to investigate the increase in mechanical properties provided by near-nano and nano-grained powders used in powder metallurgical applications. Nanocrystalline powders of light alloys (aluminum, titanium) will be produced from cryomilling operations. Consolidated forms of near-nano and nanocrystalline materials will be produced using hot isostatic pressing (HIPing) and Spark Plasma Sintering (SPS). The mechanical properties of the near-nano and nanocrystalline materials will be compared to consolidated forms of conventional materials. Initial testing indicates an increase in hardness and shear by 2-3 times from use of near-nano and nano- crystalline materials. Cryomilled powders and consolidated forms of these powders will be examined using Field Emission Scanning Electron Microscopy. Macrohardness, microhardness and shear testing will be performed to examine the mechanical properties.
Summary: Near-nano and nano-grained materials show great potential for applications in the aerospace industry. The Hall-Petch relationship cites the strengthening of materials by reducing the average crystallite (grain) size. A study is proposed to investigate the increase in mechanical properties provided by near-nano and nano-grained powders used in powder metallurgical applications. Nanocrystalline powders of light alloys (aluminum, titanium) will be produced from cryomilling operations. Consolidated forms of near-nano and nanocrystalline materials will be produced using hot isostatic pressing (HIPing) and Spark Plasma Sintering (SPS). The mechanical properties of the near-nano and nanocrystalline materials will be compared to consolidated forms of conventional materials. Initial testing indicates an increase in hardness and shear by 2-3 times from use of near-nano and nano- crystalline materials. Cryomilled powders and consolidated forms of these powders will be examined using Field Emission Scanning Electron Microscopy. Macrohardness, microhardness and shear testing will be performed to examine the mechanical properties.
