Rapidly Solidified Oxidation Resistant Niobium Base Alloys
Final rept. Jun 1987-Mar 1992
GE AIRCRAFT ENGINES CINCINNATI OH
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The initial effort concentrated on using melt spinning as the rapid solidification method for binary, ternary, quaternary and complex alloys. Ribbons were produced and given heat treatments to determine the effect on the microstructure. The ductility of the ribbons was tested in both the as-melt spun and heat treated conditions by bend testing. Four alloys were chosen for scaleup. The scaleup rapid solidification method was atomization. However, sufficient quantities and quality of powder could not be obtained for the high melting point alloys to be studied. Therefore, the decision was made to pursue ingot approaches to producing the alloys. The decision to pursue the ingot approach was made based on the difficulty of producing powder and on promising results which had been obtained on Nb-Ti alloys at GE-CRD. The Nb-Ti base alloys had been shown to have improved oxidation resistance over conventional Nb alloys, although, with a reduction in the high temperature creep strength. However, because the actual needs of the expected application were for a lower temperature, this loss in temperature capability was not considered a significant problem. Twenty alloys were chosen for screening, and produced as vacuum arc remelted VAR pins, forged into pancakes, and given one of three heat treatments to determine the effect on microstructure. Niobium Base alloys, Columbium Base Alloys, Rapid Solidification, Melt Spun Ribbons, Vacuum Arc Remelted Ingots.
- Inorganic Chemistry
- Physical Chemistry
- Fabrication Metallurgy