Directionally Solidified In Situ Metal Matrix Composites. Part 2.
BATTELLE COLUMBUS LABS OHIO
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This work constitutes Part II of an alloy screening program to identify new eutectics based on Ni, Co and Fe suitable for the manufacture of directionally solidified turbine blades operating at up to 1150 C. During this Part II, thirteen alloy systems, selected for screening during Part I, have been experimentally investigated, leading to the identification of three eutectics of potential interest Co-Al-Cr, Co-Si-Nb and Co-Cr-Zr. As a result of the overall program, Part I and Part II, a total of 9 eutectics have thus been found to meet the objectives of a melting point above 1200 C, a specific gravity below 9 gcc and a reasonably low parabolic oxidation rate. These eutectics thus have, before any development, an oxidation resistance comparable or superior to the chromium free gammagamma-delta eutectic superalloy Ni-2.55 A1-21.75 Nb wt . It is therefore expected that an alloy optimization program would improve their oxidation behavior, as compared to the gammagamma-delta alloy with 6 chromium, presently the most advanced eutectic of this class of materials.
- Metallurgy and Metallography
- Jet and Gas Turbine Engines