Development of Dispersion-Strengthened Nickel and Cobalt-Base Alloys.
Yearly summary rept. 1 Aug 64-31 Jul 65,
SYLVANIA ELECTRIC PRODUCTS INC TOWANDA PA CHEMICAL AND METALLURGICAL DIV
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Two methods were compared for preparing dispersion-strengthened nickel- and cobalt-base alloys. A technique of selectively reducing intimately mixed oxides, which were prepared by atomizing and drying a solution of the components, was more successful than one involving the coating of dispersoid particles with the matrix by vapor deposition. The conditions were determined for preparing Ni-15Mo-4ThO2 and Co-15Mo-4ThO2 powders by selective reduction. Hot pressing, hydrogen sintering, and powder rolling were evaluated for powder consolidation. The conditions for successful rolling, extrusion, and forging were investigated for Ni-15Mo-4ThO2. Process temperatures above 1200C promoted ThO2 growth to 400-500A. Deformation-anneal sequences were critical to good strength at elevated temperatures. Ultimate strengths of 21 ksi at 1800F were obtained and higher strengths seem possible. Molybdenum considerably improved the matrix strength to at least 1400F.
- Metallurgy and Metallography