Dispersion Strengthening of High Temperature Niobium Alloys
Abstract
Niobium base alloys are very attractive as high temperature materials for advanced gas turbine applications. After many conventional metallurgical approaches, a high temperature creep resistant alloy has yet to be identified which will replace nickel base superalloys. The best chance for obtaining high temperature creep resistance in these alloys is through dispersion strengthening with a stable precipitate that is introduced through rapid solidification. This would result in a very fine dispersion of nonshearable precipitates that would not coarsen upon long term exposure at temperatures in excess of 1200 C. A study has been conducted here to identify such a stable dispersion, fabricate alloys through solidification approach and characterize the coarsening of the resulting precipitates. A thermodynamic argument is presented to select candidate dispersions for evaluation. Arc melted and splat quenched alloys were fabricated and evaluated through micro-hardness measurements. An indirect assessment of particle stability is introduced which resulted in a coarsening parameter determined for each candidate precipitate at 1400 C. Microscopic examination of the more stable alloys were made via optical and thin foil TEM analyses. Tensile and strain-rate sensitivity tests were run on these alloys at 1400 C. Niobium, Dispersion strengthening, High temperature strength, Particle coarsening, Refractory metals, Niobium alloys.
Document Details
- Document Type
- Technical Report
- Publication Date
- Jul 31, 1989
- Accession Number
- ADA213829
Entities
People
- A. F. Giamei
- D. B. Snow
- D. L. Anton
- L. H. Favrow
Organizations
- United Technologies Corporation