Advanced Fluidic Controls for Integrated Propulsion Systems. Part 2. Materials and Fabrication Techniques for High Temperature Turbine Engine Controls.

摘要

An investigation of materials and fabrication techniques for fluidic components used in fluidic fuel control systems for advanced propulsion systems was conducted. The program consisted of: (1) materials selection, (2) materials evaluation and (3) fabrication techniques suitable for the usable materials. A literature survey was made to select materials that could be used for fluidic components that must operate at various temperature ranges from 500 F to 3000 F. These candidate materials were evaluated under simulated operating conditions to assess their comparative behavior and ability to withstand the anticipated environment. Several methods of fabricating the selected materials, which ranged from aluminum to ceramics, were investigated. These techniques included standard machining practices, engraving, stamping, casting, etching-diffusion-bonding, electroforming, flame spraying, and several powder metallurgy processes. For use at temperatures below 800 F aluminum appears to be the best material. Precision engraving can be used for fabrication of small numbers of these devices, but etching-diffusion-bonding or powder metallurgy with EDM cleanup is better for high volume. Nickel devices fabricated by electroforming are best for temperatures below 1200 F. For temperatures between 1000 F and 1500 F, 309 stainless steel, fabricated by etching-diffusion-bonding should be used. Either Inconel 702 or Chrome 30 are good between 1500 F and 1800 F. Above 1800 F up to 3000 F KT silicon carbide was the only material investigated capable of prolonged life and capable of withstanding thermal shock. (Author)