Tantalum modified gamma prime-alpha eutectic alloy
AssigneeUnited Technologies Corporation
InventorsDavid D. Pearson, Franklin D. Lemkey
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Abstract
This disclosure relates to directionally solidified articles produced from a eutectic alloy in the nickel-aluminum-molybdenum system with tantalum added. The articles have a microstructure consisting of a ductile matrix phase of gamma prime containing a fibrous reinforcing second phase of alpha Mo. The nominal composition of the base alloy is 6.9 weight percent aluminum, 15.2 weight percent tantalum, 18.5 weight percent molybdenum, balance nickel. The directionally solidified alloy articles of the invention are characterized by exceptional mechanical properties combined with good oxidation resistance and reasonable sulfidation resistance at elevated temperatures.
Claims7
A directionally solidified eutectic article having a composition which satisfies the following relationship:
- 12.5.+-.0.5% Mo, X% Ta, [22.+-.0.5-X%]Al balance essentially Ni,
- where all percentages are atomic percentages, and X varies from 3.4 to 7.5,
- said article having a microstructure comprising about 18 volume percent of aligned Mo fibers in a gamma prime matrix wherein from about 15.5% to about 34% of the normally occurring Al in the gamma prime matrix has been replaced by an equiatomic amount of Ta.
A directionally solidified eutectic article having a microstructure consisting of about 18 volume percent of aligned Mo fibers in a gamma prime matrix consisting of about 18% Mo, about 6.8% Al, about 16.6% Ta, balance essentially nickel.
Dependencies are inferred from the claim text.